The terminology is most clearly associated with Bertrand Russell, butthe distinction between knowledge by acquaintance and knowledge bydescription is arguably a critical component of classical ortraditional versions of foundationalism. Let us say that one hasinferential or nonfoundational knowledge thatp whenone’s knowledge thatp depends on one’s knowledgeof some other proposition(s) from which one can legitimately inferp; and one has foundational or noninferential knowledge thatp when one’s knowledge thatp does not dependon any other knowledge one has in this way. According tofoundationalism regarding knowledge, we have some foundationalknowledge, and any nonfoundational or inferential knowledge that wehave depends, ultimately, on this foundational knowledge. Whatdistinguishes classical foundationalism (or at least a prominentversion of classical foundationalism) about knowledge is theinsistence that all foundational knowledge is knowledge byacquaintance.

Historically, the distinction between knowledge by acquaintance andknowledge by description is made between two kinds ofknowledge. However, after a brief discussion ofRussell’s presentation of the distinction, we follow thecontemporary literature in focusing more on the role of acquaintancein securingjustified orrational belief. (See theentry onepistemology for more on the relation between knowledge and justification.) Thisis important both because doing so can illuminate the role thatacquaintance plays in securing knowledge (which arguably requiresjustified belief) and because we may be interested in its role as asource of justification even when we fall short of knowledge. Let ussay that one has an inferentially justified belief thatpwhen one’s belief thatp depends for its justificationon justified belief in some other proposition(s) from which one canlegitimately inferp; and one has a foundationally ornoninferentially justified belief thatp when one’sbelief thatp is justified but does not depend on any otherbeliefs for its justification. According to foundationalism regardingjustification, we have some foundationally justified beliefs, and allother justified beliefs must depend for their justification onfoundationally justified beliefs. Classical versions offoundationalism about justification hold that foundational beliefs arejustified by acquaintance. (See the entry onfoundationalist theories of epistemic justification for more on foundationalism.) As we shall see, proponents ofclassical foundationalism typically ascribe other importantphilosophical roles to acquaintance.

• 1. The Distinction
• 2. Contemporary Views on Acquaintance
• 3. Acquaintance and Noninferential Knowledge
  • 3.1 Awareness of Correspondence
  • 3.2 Demonstrative Concepts and Phenomenal Concepts
• 4. Acquaintance, Thought, andA Priori Knowledge
• 5. Acquaintance and Inferential Knowledge
• 6. Fallible Noninferentially Justified Beliefs
• 7. Criticisms
  • 7.1 The Sellarsian Dilemma
  • 7.2 The Problem of the Speckled Hen
  • 7.3 The Threat of Skepticism
• 8. Concluding Remarks
• Bibliography
• Other Internet Resources
• Academic Tools
• Related Entries

1. The Distinction

To get clear on the distinction between knowledge by acquaintance andknowledge by description, let us briefly examine how its originator,Bertrand Russell, characterized it (see Russell 1910–11 and1912: Ch. 5). First, what is meant by “acquaintance” and“description”?

We shall say that we haveacquaintance with anything of whichwe are directly aware, without the intermediary of any process ofinference or any knowledge of truths. (Russell 1912: 78)

I say that I amacquainted with an object when I have adirect cognitive relation to that object, i.e., when I am directlyaware of the object itself. When I speak of a cognitive relation here,I do not mean the sort of relation which constitutes judgment, but thesort which constitutes presentation. In fact, I think the relation ofsubject and object which I call acquaintance is simply the converse ofthe relation of object and subject which constitutes presentation.That is, to say thatS has acquaintance withO isessentially the same thing as to say thatO is presented toS. (Russell 1910/11: 108)

Russell thus characterizes acquaintance as a relation ofdirectawareness, a relation in which, as Russell and some others haveput it, something is “presented” or simply“given” to the subject (see e.g., Lewis 1929 and 1946;Moser 1989: 80ff.; Fales 1996.) Various positions can accept some sortof distinction between direct and indirect “awareness”:roughly, an awareness ofX is indirect if it depends onawareness of something else, and direct otherwise. But thischaracterization of the distinction leaves open what counts as directawareness.

What distinguishes acquaintance is, minimally, the following twoclosely related features. First, it is a nonjudgmental andnonconceptual form of awareness. Judgments, thoughts and concepts areessentiallyintentional or representational in nature, i.e.,they areabout orrepresent other things.Acquaintance with something does not consist in forming any judgmentor thought about it, or in having any concept or representation of it.(In the second passage above Russell does characterize it as a special“cognitive” relation, but one must immediately wonder whatthis means given that he explicitly denies that it is judgmental innature.) Second, it is a form of awareness constituting a real,genuine relation, a relation that cannot obtain without itsrelata (the things or items related). One cannot beacquainted with something that does not exist. Acquaintance is thuslike the relation of kicking or throwing, for one cannot kick or throwwithout there being something that is kicked or thrown—somethingthat is the object of the kicking or throwing. (Of course, these arenot forms ofawareness!) In contrast, judgments and conceptsmay represent or be about things that don’t exist. Philosopherssometimes refer to this second feature by saying that acquaintance is“infallible”. However, this term is most often used torefer to a property ofbeliefs: roughly, a belief isinfallible if it is immune to error or is guaranteed to be true. Giventhe first feature above, being acquainted with something is not to beunderstood in terms of having a belief or judgment about it, not evenan infallible one.

By a “description” Russell means any phrase of the form“a so-and-so” (an “ambiguous” or“indefinite” description) or “the so-and-so”(a “definite” description), though he focuses on thelatter in his discussion of knowledge by description. Russell’sdefinition of knowledge by description builds naturally on this: Toknow some thing or object by a definite description is to know that itis the so-and-so or that the so-and-so exists, i.e., that there isexactly one object that is so-and-so (Russell 1912: 82–3). OnRussell’s view, proper nouns, and most common words, are reallydisguised descriptions (1912: 84–5). We might claim to know whoJack the Ripper was, that he was a vicious human being, and so on, butwe can only think of and know the individual about whom the claim ismade through a description of that individual—Jack the Ripper isthat person (whoever he was) who committed certain atrocities inLondon in 1888. We have no “first hand” knowledge of theperson about whom our judgment is made—we don’t even have“first hand” knowledge that only one individual committedthe murders or, for that matter, that the murders took place. Putanother way, we are not directly acquainted with either the crimes orthe perpetrator of those crimes since he is long dead and we havesurely never met him.

Talk of descriptions naturally suggests the use oflanguage,and as we have just seen, Russell himself often characterizesdescriptions in linguistic terms, e.g., asphrases havingsuch-and-such a form. However, for Russell, description does notessentially involve the use of words or phrases of a language; itinvolves the use or application ofconcepts. To knowsomething “by description” does not require the use oflanguage or linguistic terms, but it does require the use orapplication of concepts.

The example of Jack the Ripper just given, and many of Russell’sexamples, are at best misleading. They trade on that commonplacedistinction between things we know “first hand” and thingswe have only heard about or read about—the things that have beendescribed to us.

But our commonsense way of making the distinction soon goes by thewayside. Most philosophers wedded to some notion of acquaintance endup rejecting the idea that we have acquaintance even with bread-boxsized objects, immediately before us, under ideal conditions ofperception. The test to determine with what we are acquainted is oftenreminiscent of the method Descartes recommended for finding securefoundations of knowledge—the method of doubt (see Russell 1912:74; Price 1932: 3). If you are considering whether you are acquaintedwith something, ask yourself whether you can conceive of being in thisvery state when the putative object does not exist. If you can, youshould reject the suggestion that you are directly acquainted with theitem in question. Based on possibilities of error about physicalobjects from illusion, hallucination and dreams, it seemed to mostthat we could rule out acquaintance with physical objects, futureevents, other minds, and facts that involve any of these asconstituents. Consider, for example, physical objects. It seems thatthe evidence that my experiences give me right now for supposing thatthere is a computer before me is perfectly consistent with thehypothesis that I am now having a vivid dream or a vividhallucination. If this is right, then the experiential evidence Ipossess cannot be the computer or any of its constituents. Neither thecomputer, nor any of its constituents, need be present in that vividdream or hallucination. Even when our evidence for the presence ofphysical objects seems as good as we can get, then, we are notacquainted with physical objects or their constituents. (However, somehave recently defended the view that we can be acquainted withphysical objects in perception. See, for example, Johnston 2004.)Traditionally, acquaintance theorists have taken the most promisingcandidates for entities with which we can be acquainted to beconscious states of mind (e.g., an experience of pain, a sensation ofred) and their properties (e.g., painfulness, redness). Russell andmany other acquaintance theorists also take themselves to beacquainted withfacts, i.e., with something’s havingsome property—at least mental facts (e.g., my being in pain, mydesiring food, my experiencing red).

What about the possibility of acquaintance with ourselves? Can anindividual be directly acquainted with him or herself? Russell takesthe question of whether we are ever acquainted with the self to be adifficult one. He says that acquaintance with the self is “hardto disentangle from other things,” but tentatively concludesthat “it is probable, though not certain, that we haveacquaintance with Self” (1912: 78–81.) However, he laterdenies that we have acquaintance with the self (see Russell 1914: partIII). In a recent paper, Duncan (2015) uses the method of doubt, orsomething very much like it, to argue that we are acquainted withourselves.

Let us now return to the primary question of this section: how shouldwe understand the distinction between knowledge by acquaintance andknowledge by description? When philosophers speak ofknowledge they typically mean to be discussing knowledge oftruths or propositional knowledge, knowledge that involves a belief orjudgment in some true claim or proposition. As introduced by Russell,the distinction sometimes seems to be that between noninferential orfoundational knowledge on the one hand, and inferential ornonfoundational knowledge on the other. Roughly, one hasnonfoundational or inferential knowledge thatp whenone’s knowledge thatp depends on one’s knowledgeof some other proposition(s) from which one can legitimately inferp; and one has foundational or noninfrential knowledge thatp when one’s knowledge thatp does not dependon any other knowledge one has. Knowledge by acquaintance isfoundational knowledge because it depends on one’s acquaintancewith the object itself, or with properties of or facts about theobject, and not on any further knowledge of truths. Knowledge bydescription, in contrast, always depends on some further knowledge oftruths for support; as Russell puts it, knowledge by description“always involves…some knowledge of truthsas itssource and ground” (1912: 72–3, emphasis added).

This seems to be a natural and relatively straightforward way ofdrawing the distinction. However, there may seem to be a problem withthis way of drawing the distinction, at least as an interpretation ofRussell, for he denies that knowledge by acquaintance is knowledge oftruths:

Knowledge of things, when it is of the kind we call knowledge byacquaintance, is essentially simpler than any knowledge oftruths, and logically independent of knowledge of truths, though itwould be rash to assume that human beings ever, in fact, haveacquaintance with things without at the same time knowing some truthabout them. (Russell 1912: 72)

We have already seen that for Russell acquaintance is nonjudgmental ornonpropositional; to be acquainted with something is to beawareof it in a way that does not essentially involve beingawarethat it is so-and-so. Russell seems to be extending this toknowledge by acquaintance: it is knowledgeof something, andlogically independent of knowledgethat something isso-and-so. Nor is this usage of the term ‘knowledge’ andits cognates strange: we do indeed talk about knowing people andcities. This might suggest that we should draw the distinction betweenknowledge by acquaintance and knowledge by description not as onebetween foundational and nonfoundational knowledge of truths, but asone between knowledge of truths and knowledge of something other thantruths. Indeed, as we have seen, Russell at one point definesknowledge of something by description simply as knowledge that it isso-and-so, notfoundational knowledge that it is so-and-so(1912: 84–5). But then, what more thanacquaintance isinvolved inknowledge by acquaintance? It is difficult tofind an answer from Russell.

It is tempting to suppose that Russell equivocates between therelation of acquaintance and the special kind of knowledge of truth(foundational knowledge) whose sole source is acquaintance. That weordinarily talk about knowing things and people might encourage thisequivocation. Moreover, perhaps the fact that acquaintance is a formof awareness of the most direct, most secure kind, and is fundamentalto all knowledge of truths, led Russell to think it deserves to becalled “knowledge” of the thing in question. The issuehere is largely terminological. In order to guard against confusingacquaintance on the one hand withfoundational knowledgeof truths acquired by acquaintance on the other, and facilitatean examination of the relation between them, we should be more carefulthan Russell and restrictknowledgeby acquaintanceto foundational knowledge oftruths. By contrast, one canhaveacquaintance with items that are not truths, items thatcannot be said to be true or false. Knowledge by description, on theother hand, is nonfoundational knowledge of truths; it “alwaysinvolves…some knowledge of truths as its source andground” (Russell 1912: 72–3). We adopt this usage in whatfollows.

For classical foundationalists like Russell, all knowledge of truthsultimately depends on foundational knowledge of truths acquired byacquaintance. But how exactly does acquaintance contribute to thisknowledge of truths? If acquaintance is nothing like a judgment orbelief, and if the items with which we are acquainted are themselvesneither true nor false, how do we get any knowledge oftruthsout of acquaintance? We turn to this question insection 3.

First, however, let us briefly discuss contemporary views regardingthe nature and objects of acquaintance.

2. Contemporary Views on Acquaintance

We said above that what distinguishes the classical, Russellian notionof acquaintance is, minimally, that (i) it is a non-intentional formof awareness: acquaintance with something does not consist in formingany judgment or thought about it, or applying any concepts to it; and(ii) it is real relation requiring the existence of itsrelata; one cannot be acquainted with some thing, property orfact that does not exist. Let us use the label “acquaintancetheory” broadly to stand for any view, in the philosophy of mindor epistemology, in which acquaintance so understood plays a centralrole. There has been a resurgence of interest in acquaintance theoryin the last 25 years or so. Contemporary proponents include BonJour(2001, 2003), Chalmers (2010), Fales (1996), Fumerton (1995, 2001,2016), Gertler (2001, 2011, 2012), Hasan (2011, 2013), McGrew (1995,1999), Moser (1989), Stoutenburg (forthcoming), and Taylor (2013). Aswe shall see, some of these philosophers depart from Russell insignificant ways. However, like him, they are all committed to theexistence and philosophical significance of a direct, nonjudgmentalform of awareness (indeed, many of them call it“acquaintance”) and this warrants treating them all as“acquaintance theorists.” Most of them also explicitlyendorse classical foundationalism: like Russell, they hold that allknowledge or justified belief ultimately depends on a foundation ofknowledge or justified belief acquired by acquaintance. There areconsistent ways to accept acquaintance theory without acceptingclassical foundationalism. For example, some might agree that we dohave some knowledge by acquaintance and appeal to such knowledge inthe dualism debate in the philosophy of mind (see the entry onqualia: the knowledge argument), without endorsing the claim that all knowledge or justified beliefmust depend, ultimately, on acquaintance. However, unless otherwiseindicated, we use “acquaintance theory” and“classical foundationalism” interchangeably.

Acquaintance is typically taken to be simple and thus indefinable. Thephilosophers for whom acquaintance plays a critical philosophical roleare usually unapologetic about their inability to define the concept(e.g., Fumerton 1995: 76–7). They will quite plausibly arguethat analysis requires conceptual “atoms”—simpleideas out of which other ideas are built. The concept of acquaintance,for them, is arguably the most fundamental concept on which allepistemology, and perhaps all philosophy of mind, is built. Still, onephilosopher’s conceptual atom is another’s completemystery, and unless one can convince oneself that one understands whatacquaintance is, one will not be able to understand views that invokeit.

To be sure, one can use metaphors of one sort or another to explainthe concept, but the metaphors are as likely to be misleading ashelpful. The pain one feels, one might say, is “before”the mind. There is nothing “between” one and the pain onefeels. But these are spatial metaphors and the relation betweenone’s self and that with which one is acquainted is not reallyall that much like a spatial relation. Even if there is no objectbetween a chair and a table, the space between them is composed ofother spaces, and in virtue of this we can compare different spaces ordistances quantitatively; in contrast, acquaintance with something isnot composed of further relations, and so different relations ofacquaintance cannot be compared quantitatively in a parallel way. Onecan add that acquaintance is a non-intentional or nonjudgmental formof awareness, and that one cannot be aware of something in this waywithout its existing, but the concept of awareness remains unanalyzed,and these conditions merely assert that, and shed no light on why,acquaintance has these features.

If the usual view is correct and acquaintance is simple andunanalyzable, nevertheless, perhaps one can point to it by describingit in some revealing way that is unique to it. Unfortunately, theattempt at pointing involves controversial presuppositions. Butimagine the following sort of familiar case. One is in pain but as oneengages in an interesting conversation, one doesn’t notice thepain for a while. After the conversation ends, one is again aware ofthe pain. There are two possibilities. One is that the paintemporarily ceased. The other is that the pain continued, but that thesubject was temporarily unaware of it. On the supposition that thelatter makes sense, acquaintance is that relation the subject had topain before the conversation, the relation that ceased during theconversation, and that began again shortly thereafter.

The acquaintance theory is controversial, the idea that some thingscan simply be “given” to the subject has often beendenounced as a “myth” (Sellars 1963), and those committedto acquaintance disagree about its nature and its objects. All thismay seem to be a source of embarrassment for the acquaintancetheorist, for how could doubts and disagreements arise regarding whatis supposed to be immediately and transparently present toconsciousness? But there is no need for embarrassment. For theproponent of acquaintance or the given, the lesson of these doubts anddisagreements is that from the fact that something is given it doesnot follow that everything about the nature of the given or itsepistemic role is itself given; “profound puzzles can arise, andlegitimately demand solution, even in connection with that which isindubitable” (Fales 1996: 2). (For some elaboration on theacquaintance theorist’s response to the existence of such doubtsand disagreements, see theconcluding remarks.)

Some acquaintance theorists seem to disagree about the nature ofacquaintance. Fumerton regards acquaintance as asui generisrelation; it “cannot be informatively subsumed under agenus, and…cannot be analyzed into any less problematicconcepts” (1995: 76). It is an irreducible relation that canhold between a self and some object, state, property, or fact. LikeFumerton and other acquaintance theorists, BonJour agrees that thereis a form of awareness that is nonjudgmental and that is“infallible” in the sense that it requires the existenceof its object; and like other classical foundationalists, he takes alljustified beliefs (or at least all justified empirical beliefs) todepend, ultimately, on this form of awareness. Unlike Fumertonhowever, BonJour (2003) takes this awareness to be a“built-in” or intrinsic to conscious or experientialstates. On this view, awareness is not a relation between the self andsomething else, but is an intrinsic feature of the mental stateitself, though one that is still relational in the sense that it isdirected at something; and what one is aware of is just the specificcharacter or content of that state of awareness. So, while Fumertontakes the fundamental awareness or acquaintance to be a relation,BonJour takes it to be an intrinsic feature of all experiences orconscious states. Awareness or acquaintance is perhaps most naturallythought of as a relation between a self and something else: wetypically talk ofpeople, animals, persons, selves, minds,etc. being awareof things, states, properties, orfacts. However, a view that regards the most fundamental sort ofawareness as an intrinsic property of certain mental states mightstill be able to make sense of such talk: to say that I am directlyaware ofX is just to say that I am in a state with“built-in” awareness ofX.

BonJour’s view is similar to the view that conscious states areself-representational in that the awareness of some content or featureof the state is itself part of that state, but it is important not tooverstate the similarity. For BonJour, conscious states are in asense, as Chisholm might put it, self-presenting, but theyare not self-representing. BonJour denies that directawareness of something is intentional or representational, or that itessentially involves athought about or representation of it.Again, like all acquaintance theorists, he takes the sort of awarenessunderlying all foundationally justified belief to be unmediated by anybelief or representation, and to guarantee the existence of itsobject: one cannot be directly aware of something that does not exist.

BonJour’s view of acquaintance seems to explain why, asproponents of the acquaintance approach tend to hold, one cannot beacquainted with external world objects or external world facts(BonJour 2001: 31). If acquaintance is a “built-in”feature of conscious states in virtue of which one can be aware onlyof intrinsic features of that very state, then on the plausibleassumption that ordinary physical objects and their intrinsic featuresare not intrinsic features of mental states, one cannot haveacquaintance with such objects or their features. On the other hand,Fumerton’s relational view of acquaintance, like the traditionalRussellian view, seems to allow for the possibility of acquaintancewith abstract entities such as universals, which some acquaintancetheorists appeal to in order to make sense of the possibility ofthought anda priori knowledge (see section 4). There is room for more work here in investigating the nature ofacquaintance and its implications.

It’s also worth noting that although talk of acquaintance oftenbrings sense-datum theory to mind, there is nothing about thecommitment to acquaintance itself that entails such a commitment.According to sense datum theory, whenever one has a sensory experienceas of some object having some propertyF, there is some objectpresent that has the propertyF. For example, if I have asensory experience as of a green triangle, then there is somethingpresent that is green and triangular. And since I could have thissensory experience even while hallucinating (at least according tosense datum theorists), this object that is green and triangular isnot a physical object. In contrast to the sense datum theorist whotreats the sensed propertyF as a feature of some object ofwhich the subject is aware, the adverbialist or advocate of the theoryof appearing treats it as a way of sensing or experiencing. To dance awaltz is not to do something or perform some act, viz., dancing, thattakes something else, a waltz, as its object, but is rather a way ormanner of dancing—dancing waltzily; similarly, to experience orhave an appearance of green is not to have an act of awareness thattakes a green object as its target, but is rather a way ofexperiencing or being appeared to—“experiencinggreenly”, or “being appeared to greenly.” Theacquaintance approach is compatible with adverbialism regarding senseexperience; one might be acquainted with experiential states, and withone’s experiencing greenly, as opposed to being acquainted withsome green object, and with its being green. (See, for example,Fumerton 1985: 94–5; McGrew 1995: 93–4; and Chalmers 2010:291.) Alternatively, some acquaintance theorists take perceptual orsensory experience to involve acquaintance withuniversals,and hope thereby to avoid problems with both the sense datum theoryand the adverbial theory. For an interesting defense of this view, seeForrest (2005). (For more on sense datum theory and adverbialism, seethe entry onthe problem of perception.)

As we have seen, the familiar experience of temporarily failing tonotice one’s pain while engrossed in conversation serves as apotential illustration of acquaintance. In at least some such cases,the pain does not disappear entirely, even though one no longernotices it. Some may be inclined to deny that one can have a painwithout being in some way aware or conscious of the pain. (BonJour2003 seems to hold this view. See also, Chalmers 2010: 291.) But itdoes seem that the sort of case Fumerton describes is a genuinelypossible, indeed frequent, occurrence, and that the act of noticingone’s pain is not a mere predication of one concept to another(e.g., predication of the conceptpain to the conceptpresent experience), but an act of fixing one’s mentalgaze, so to speak, on some particular feature or aspect of one’sexperience. A relation of acquaintance seems to provide just what isneeded here: if acquaintance is a relation that one can stand in toone’s experience or to some feature of the experience, thatwould account for the possibility of having an experience ofsomething, like a pain or some other sensation, temporarily failing tonotice it, and then noticing it again. Can BonJour’s accounthandle such cases as well? BonJour does qualify the awareness requiredfor justification in a particular way that may help him to make senseof such cases. I can be conscious of or directly aware of a great manyfeatures simultaneously, but canattend to only a fewfeatures at any one time. For BonJour, attention is not entirelyseparate from the built-in awareness, but is “built upon it viawhat might be described as a selective focus” (2003: 192). So,while I cannot be in pain without being conscious of or aware of thepain, I can be in pain without attending specifically or selectivelyto the pain. Gertler (2001) presents an account of the justificationof introspective beliefs that takes attention as a primitive, directawareness. Though the connection to acquaintance is not explicitthere, in more recent work Gertler defends the same view as an“acquaintance approach” to introspective knowledge, socalled because it is inspired by Russell’s theory ofacquaintance (2011, 2012). She seems to regard demonstrative attention(the sort of attention that makes possible introspective judgmentswith demonstrative content, e.g., “I am experiencingthis property”) as made possible by acquaintance(2012). Taylor (2013) discusses a number of phenomenological andtheoretical advantages to identifying acquaintance with attentiveawareness.

To summarize, there is a great deal of agreement among philosopherswho adopt the acquaintance approach: they all take there to be anepistemically fundamental awareness that is unmediated andnonconceptual, a form of awareness that secures the existence of itsobject. There seems to be some disagreement regarding the nature ofacquaintance, e.g., whether it is fundamentally a relation between theself and the target of awareness, or an intrinsic,“built-in” aspect or feature of some mental states; andwhether it consists in attention. There may also be some disagreementregarding the possible objects or targets of acquaintance. And, as weshall see below, there is also some disagreement regarding the properanalysis of noninferential knowledge or justified belief, and howacquaintance figures in that analysis.

3. Acquaintance and Noninferential Knowledge

Foundationalism regarding justification is often motivated by someversion of the regress argument. (Foundationalism regarding knowledgecan be motivated by a parallel version of the regress argument, put interms of knowledge rather than justification.) The argument goesroughly as follows. By definition, any beliefB that is aninstance of nonfoundational or inferential justification must dependon some inference or inferential relation to other beliefs. It seemsthat this dependence on other beliefs must take one of four forms: (i)the belief depends inferentially on other beliefs, and the latterbeliefs on yet other beliefs, to infinity; (ii) the inferenceeventually loops back to beliefB, so thatB depends onitself for its justification; (iii) the belief ultimately depends onother beliefs that are not themselves justified; or (iv) the beliefultimately depends on a foundationally justified belief: a belief thatis justified but that does not depend on other beliefs for itsjustification. The foundationalist argues that each of thealternatives to (iv) is seriously problematic: (i) An infinite regressis vicious, and even if it isn’t, this is no help for finiteminds like our own. (ii) Circular reasoning is vicious; one cannotdepend, even in part, on a belief thatp in order to justifybelieving thatp. (iii) One cannot generate justification byrelying on unjustified beliefs (“garbage in, garbageout!”). So that leaves (iv): if any of our beliefs arejustified, then they must either be foundationally justified ordepend, ultimately, on foundational beliefs for theirjustification.

Some worry that (iv) is no better, and possibly worse, than thealternatives: how could a belief be justified, or be an instance ofknowledge, without depending on other beliefs? The acquaintancetheorists seems to have an answer: acquaintance with facts is designedto end the potentially vicious regress of justification. But howexactly do we get noninferential knowledge or justified belief out ofacquaintance? An acquaintance theorist who accepts the correspondencetheory of truth can provide a relatively straightforward answer. Onwhat is surely the classical conception of truth, truth consists incorrespondence between the truth bearer (the proposition, thought, orbelief) and the representation-independent fact to which that truthbearer corresponds (see the entry onthe correspondence theory of truth). The question of what constitute the primary bearers of truth value isa matter of enormous controversy. Suppose, though, for this discussionthat it is a thought that is the primary bearer of truth value(sentences are derivatively true or false when they express thoughtsthat are true or false).

On a simple version of this view (perhaps too simple to have anycontemporary proponents, but an instructive place to start), we havenoninferential or foundational knowledge thatP if and onlyif we have the thought thatP while we are directlyacquainted with the fact thatP—i.e., a truth-maker ofthe thought thatP. So if I am the kind of being who has theconceptual sophistication to form thoughts, and I have the thoughtthat I am in pain while I am acquainted with the fact that I am inpain, I have the most secure and basic sort of knowledge of truth.

We said earlier that acquaintance is not itself judgmental orpropositional, and so does not have truth value—it is a form ofawarenessof something, not awarenessthat somethingis so-and-so. However, this leaves open the possibility that theobject or target of acquaintance—that with which one isacquainted—be propositional or have truth value. If I amacquainted with the proposition or thought that I am in pain then I amacquainted with something that has truth value, even thoughacquaintance itself is not to be understood as propositional innature. The simple view we are considering might hold that one hasfoundational knowledge that one is in pain if, in addition to beingacquainted with one’s being in pain, one is also acquainted withthe thought or proposition that one is in pain.

This view of how we get from acquaintance to noninferential knowledgeor justified belief is problematic, however. First, the account seemstoo weak, for acquaintance with a fact that corresponds to a thoughtisnot sufficient for justification, let alone knowledge.Suppose that I am aware of the fact of there being a decagon in myvisual field. Suppose that I also believe that there is a decagonin my visual field, but my belief is little more than a lucky guess,or that I only believe this because I think there always is a decagon in my visual field. Intuitively, the belief is not justified.Second, the account seems too strong, for the requirement thatone’s thought correspond to reality rules out the possibility offalse noninferentially justified belief. The resultinginfallibilism regarding foundational belief is aprima facieimplausible requirement, and arguably has radically skepticalconsequences. This second problem will be taken up later, insection 6.

Contemporary acquaintance theorists have defended more sophisticatedversions of the view. In response to the first problem, theacquaintance theorist can agree that in order to be justified it isnot enough that the subject be acquainted with a fact that happens tocorrespond to what is believed. It will be useful to divide theresponses into two broad camps, introduced in the next twosub-sections: those that require, in addition to acquaintance withsome fact, some sort of awareness of the correspondence between thethought and what it is about (or perhaps awareness of some otherepistemically relevant relation—see the end ofsection 6), and those that require that the beliefs involve demonstrative orphenomenal concepts.

3.1 Awareness of Correspondence

Why is acquaintance with a fact that corresponds to one’sthought not sufficient for justification? Consider the examplementioned above. I can be directly aware of there being a decagonin my visual field, believe that there is a decagon in my visualfield, and yet I might fail to be justified if I believe this notbecause I am unaware of there being a decagon in my visual field,but because my belief was little more than a guess, or because Ibelieve (without justification) that there are always decagons inmy visual field. This might suggest that the acquaintance theoristneed only add some condition to the effect that the subject mustbelieve thatp because she is aware of a corresponding fact.Most acquaintance theorists will not be entirely happy with thissuggestion. Acquaintance theorists are paradigm internalists aboutjustification: they typically accept the internalist thesis that onecan be justified in believing thatp only if one has a reasonor evidence in favor ofp’s truth, something in virtueof which the truth ofp is not a mere accident from his orher perspective; externalists deny this thesis (see the entry oninternalist vs. externalist conceptions of epistemic justification). Acquaintance theorists are therefore likely to insist that awarenessof the fact thatp cannot provide justification for believingthatp unless the subject is in some way also aware of therelevance of that fact to the truth ofp. This awareness ofthe relevance of some fact to the truth ofp might beaccepted as part ofthe epistemic basing relation, and for this reason necessary for “doxasticjustification”: in order forS tobe justified inbelieving thatp on the basis of some ground or evidencee,S must be aware of the relevance ofe top’s truth, and believe thatp directly becauseof this awareness. Alternatively, the awareness of the relevance ofsome fact to the truth ofp might be taken as a condition foreven “propositional justification”: in order forStohave or possess noninferential justification for believing thatp (even ifS does not believe thatp, ordoes not properly base the belief on that justification),Smust not only be acquainted with some fact that is relevant to thetruth ofp, but must also be aware, in some way, of therelevance of that fact to the truth ofp. Moser (1989:141–5) seems to endorse a view of the former sort, whileFumerton (1995) endorses the latter. (While the distinction betweenpropositional and doxastic justification is important, to simplifydiscussion, we do not distinguish carefully between these below.)

According to Fumerton, a belief thatp is noninferentiallyjustified if and only if the subject is acquainted with the thoughtthatp, acquainted with a corresponding fact, and acquaintedwith the correspondence between the thought thatp and thatcorresponding fact. (Fumerton qualifies the analysis to accommodatefalse noninferentially justified beliefs, but let us ignore this forthe moment.) Suppose that I am acquainted with my having a headache,acquainted with the thought that I have a headache, and acquaintedwith the correspondence between the thought that I have a headache andmy having a headache. When this happens, everything constitutive ofthe thought’s being true is there directly before my mind.Epistemically speaking, it doesn’t get any better than this.

BonJour’s account of noninferentially justified belief similarlyrequires not only direct awareness of some fact, but also a“direct recognition” of the “fit”between that fact and the conceptual description embodied in thebelief (BonJour 2003: 73–4). Both Fumerton and BonJour thusrequire some sort of awareness or grasp of the correspondence betweena thought and what it is about. However, while Fumerton’sacquaintance with correspondence is acquaintance with a fact and not ajudgment that a proposition is true, BonJour seems to understand the“recognition” of fit or correspondence as judgmental orpropositional—something like a judgment to the effect that theconceptual description embodied in the belief fits or correctlydescribes one’s experience. This naturally leads to thequestion, must this judgment of fit itself be justified? And if so,what justifies it? BonJour insists (2003: 65 and 193) that while thejudgment of fit requires justification, its justification depends onone’s direct awareness of the propositional content believed anda direct awareness of the relevant experiential feature, and thatthere is no need for any further awareness, judgmental or otherwise.This response seems problematic, however, for we now have at least onesort of belief or judgment, the higher-order judgment of fit itself,that is noninferentially justified without there being any awarenessor recognition thatits propositional content fits the facts.If a judgment of fit is required for the first-order belief,shouldn’t the same be required for the judgment of fit itself?But if it is required then we are off on a regress of judgments offit, with no foundation in sight. This suggests, in line withFumerton’s view, that if some awareness of fit or correspondenceis required, then it must at the most fundamental level be anonconceptual and nonpropositional awareness of fit or correspondence.

3.2 Demonstrative Concepts and Phenomenal Concepts

Not all acquaintance theorists require acquaintance with thecorrespondence (or some other epistemically relevant relation) betweensome thought or proposition and a distinct fact for one to haveknowledge by acquaintance. Rather than require a further act ofawareness, some acquaintance theorists add constraints to the natureof the foundational belief or the manner in which it is formed so thatacquaintance with some mental state or mental feature provides part ofthe content of the belief itself, and does so in such a way as toguarantee the truth of the belief. For example, according to McGrew(1995, 1999), for any object of acquaintance or direct awareness, itis possible to form a belief in which a demonstrative concept refersdirectly to it. By virtue of my acquaintance with a painfulexperience, I believe directly of it that it exists, or that theproperty (painfulness) is instantiated. We could express the beliefroughly by saying “I am experiencingthis”(McGrew 1995, 1999), or “this is instantiated (in me,now)” (Gertler 2012). For this kind of belief (unlikemost other beliefs regarding contingent facts), to genuinelyunderstand or grasp the content of the beliefis to grasp itstruth.

It is important to see how this is different from the standard view ofdemonstrative concepts. On the standard view, a demonstrative conceptis something like anindexical (see the entry onindexicals). Consider indexical concepts likeI, here, andnow.The reference of these concepts is fixed by the context, by thespeaker or thinker’s identity, location, and time. On thestandard view, thecontent of a token indexical concept isconstituted by or essentially tied to the actual referent, much as thecontent of the conceptwater is constituted by or essentiallytied to the actual referent in the environment (at least according tocontent-externalism about natural-kind concepts). The standard view ofdemonstratives is similar. The actual referent of a tokendemonstrative concept is taken to constitute or be essential to itscontent, but unlike the indexical concepts just discussed, thereference of a demonstrative is not fixed automatically by thespeaker’s identity, location and time; something else is neededto fix the reference. Different views of the reference-fixing factorhave been proposed, with the main suggestions being that reference isfixed by one or more of the following: ademonstration,understood as an act of pointing or gesturing or some similarbehavior; anintention to point or refer to an object of acertain kind, or an object satisfying some description; or someappropriate causal or spatial relation (e.g., between theagent’s pointing or utterance and some item in the environment).What is important for our purposes is that none of these views takethe reference-fixing to be donepurely by acquaintance or directawareness. On McGrew’s view, the reference is fixed bydirect awareness, and not by acts of pointing or gesturing,by the subject’s intentions to refer to a certain sort of thing,or by causal relations.

McGrew is not alone in holding that experiential or phenomenalfeatures can, by virtue of our direct awareness of them, constitutethe content of a special class of concepts. Gertler (2001, 2011,2012), Chalmers (2003, 2010), and Nida-Rümelin (2004) defendviews very much in the same spirit. Gertler (2001) distinguishesbetween ordinary demonstratives, which typically involve an intentionto pick out an entity that satisfies some description, and apure demonstrative, which picks out its referent solely by afundamental act of attention or acquaintance. Chalmers (2003, 2010)defends a similar view according to which some noninferential beliefsare justified by virtue of involving a “direct phenomenalconcept,” a concept whose content isconstituted by aphenomenal quality with which one is acquainted. The view is supportedby considering Frank Jackson’s (1982) hypothetical case of Mary,who has learned all of the physical facts about color but has neverhad a visual experience in color until one day she experiences red.Jackson argues there that Mary thereby learns some new information;she acquires some new knowledge. And since Mary already knows all thephysical facts about color, this new item of knowledge must, Jacksonargues, be of a non-physical fact. Chalmers (2010) andNida-Rümelin (2004) argue that it is difficult to make sense ofthe epistemic progress of subjects like Jackson’s Mary unless weaccept that there is a core phenomenal concept whose content isconstituted by an underlying phenomenal or experiential quality withwhich the subject is acquainted. Chalmers (2004) relies on theacquaintance approach to phenomenal concepts to defend the knowledgeargument for dualism—i.e., the claim that Mary acquires newknowledge, and that this must be knowledge of anon-physicalfact. (He notes (2003: 227) that demonstratives are naturallyused to express direct phenomenal concepts (e.g., “I amexperiencingthis quality”), and that there may be asense in which a direct phenomenal concept is a“demonstrative” concept, but he avoids such a label atleast in part because of the danger of confusing direct phenomenalconcepts with demonstrative ones as usually understood.) It is worthnoting that, in contrast, some philosophers appeal to knowledge byacquaintance to make sense of Mary’s new knowledge in order tooppose, rather than to support, the success of the knowledge argumentfor a dualistic conclusion (e.g., Conee 1994 and Balog 2012).

McGrew endorses classical foundationalism, taking all our empiricalknowledge to rest on a foundation of knowledge that is had byacquaintance or direct awareness, and in particular on demonstrativebeliefs. While Chalmers and Gertler seem somewhat sympathetic toclassical foundationalism, they have been concerned primarily todefend the claim that at least some introspective beliefs or beliefsregarding one’s own phenomenal states constitute the most securesort of empirical, noninferential knowledge or justified belief, andthat these beliefs owe their privileged epistemic status toacquaintance. Thus, Gertler (2012) endorses the acquaintance approachfor a limited class of introspective judgments, and leaves it openwhether there could be other sources of noninferentialjustification.

Some worry that the demonstrative strategy yields beliefs with verylittle content (Sosa 2003b). If, however, we keep in mind that thecontent of the belief is secured by the subject’s directawareness of the phenomenal features themselves then it is unclear whythe content can’t be as rich as the features attended to. A moreserious worry in the vicinity is that, insofar as a demonstrativeconcept is onlypossessed by the subject for as long as theparticular experience or property instance is given or presented, wehave no account of how concepts that the subject can possess over timeas experiences change can be applied directly to experience. Even ifpurely demonstrative beliefs have an important role to play at thefoundations, many classical foundationalists will want to allow thatsome concepts that we already possess can be compared directly toexperience to yield foundational knowledge. Unless some foundationalbeliefs involve such enduring concepts, concepts whose connections toother concepts we have had the opportunity to grasp, it will bedifficult to see how these foundations could support various otherbeliefs that are intuitively justified. To accommodate suchfoundations, Chalmers (2003) suggests that subjects might retainknowledge of what an experience is like even after the experience islong gone, by acquiring what he calls astanding phenomenalconcept. Standing phenomenal concepts are still very much like directphenomenal concepts in that the content is essentially tied tophenomenal properties. While Chalmers does not say exactly whatdetermines the content of such concepts, he finds it

plausible that their content is determined by some combination of (1)non-sensory phenomenal states of a cognitive sort, which bear arelevant relation to the original phenomenal quality inquestion—e.g., a faint Humean phenomenal ‘idea’ thatis relevantly related to the original ‘impression’; (2)dispositions to have such states; and (3) dispositions to recognizeinstances of the phenomenal quality in question. (2003: 239)

4. Acquaintance, Thought, andA Priori Knowledge

So far we have been talking primarily about the role of acquaintancein securing a special kind of knowledge. There is, however, anothercrucial role acquaintance has been thought to play. For philosopherslike Russell, acquaintance secures not only the objects of knowledgebut the objects of thought itself; it explains not only how knowledgeis possible, but also how thought is possible. This is so not just fora special class of thoughts about experiences or experientialqualities as some hold (seesection 3.2, on demonstrative and phenomenal concepts), but for thought ingeneral. The idea actually goes back to the empiricists who claimedthat all simple ideas have their source in experience. When refinedthe suggestion probably amounted to the view that all simple ideas arederived from objects or properties with which we are acquainted or ofwhich we are directly aware. On Russell’s version of the view,whenever you form a thought, the components of that thought are itemswith which you are acquainted:

Every proposition which we can understand must be composedwholly of constituents with which we are acquainted.(1912: Ch. 5)

You can, to be sure, think of Jack the Ripper, but the thought whenanalyzed is broken down into constituents each of which is somethingwe can apprehend directly. The name “Jack the Ripper” getsreduced to a description embedded in a quantified statement. Thethought thatJack the Ripper is vicious just is the thoughtthat there exists one and only one individual who has certainproperties—e.g., who is the most famous 19^th Centurymurderer—and who also has the property of beingvicious. Russell has always struggled with the question of how to viewour understanding of the quantifier—expressions of quantity suchas ‘a’ or ‘the’—but it is clear that hebelieved that we have the capacity to entertain in thought (directly)the properties (universals) picked out by predicate expressions. Ifhaving a thought essentially involves acquaintance with universals,then it ceases to be a mystery how thought can represent the world,since the world partly consists in instances or exemplifications ofuniversals; and if a thought involves acquaintance with universalsthat happen to be instantiated or exemplified by some object ofacquaintance, then it makes sense that one can, at least in somecases, directly compare and become acquainted with the correspondenceor fit between the two.

The acquaintance theorist is in a position to offer a different glosson the traditional distinction betweena priori knowledge of necessary truth anda posteriori or empirical knowledgeof contingent truth. On the classical acquaintance theory, knowledgeof both truths has the same source—acquaintance with facts. Thedistinction lies with theobjects of acquaintance. When I amacquainted with my being in pain, that can give me knowledge of thecontingent truth that I’m in pain. When I am acquainted with theproperty of being red, the property of being yellow and the relationof being darker than holding between them, that can give me knowledgeof the necessary truth that red is darker than yellow. When I amacquainted with being triangular and being trilateral and the relationof inclusion holding between them, that can give me knowledge of thenecessary truth that triangles are trilateral. When I am acquaintedwith being a circle, and having corners, and the relation of exclusionbetween them, that can give me knowledge of the necessary truth thatcircles have no corners. For similar views of the nature of thoughtand thea priori, see Bealer (1982: Ch. 8, especially187–90) and BonJour (1998: Ch. 6).

5. Acquaintance and Inferential Knowledge

An acquaintance theorist aiming to provide a general account ofknowledge owes us an account not only of noninferential knowledge, butalso of inferential knowledge. How can we get at least reasonable orjustified belief when we are not directly acquainted with the truthmakers of those beliefs, the facts that make the beliefs true? Again,we stress that the question we are concerned with here is not how wecan get knowledge of truths in contrast to knowledge of somethingother than a truth. We have already suggested that knowledge byacquaintance should be thought of as knowledge of a truth madepossible by acquaintance with the truth maker. The question, rather,concerns how we can get knowledge of a truth when we are notacquainted with the truth maker. For the classical acquaintancetheorist, that question, in turn, reduces to the question of how wecan acquire knowledge through inference.

There are at least two possible answers the acquaintance theoristmight give. A view we might call inferential externalism suggests thatto acquire inferential knowledge thatQ by inferringQ fromP it is enough thatP makes highlyprobableQ. The relation of making probable, itself, can beinterpreted in many different ways. A detailed discussion ofinterpretations of probability would take us too far afield, so let usbe content with a few very brief remarks (see the entry oninterpretations of probability). One might try to understand probability in terms of frequency.Roughly the idea is thatP makesQ probable whenP andQ form a pair of propositions of a certainkind, where usually when the first member of a pair of propositions ofthat sort is true then so is the second. Alternatively, somephilosophers would follow Keynes (1921) and argue that there arerelations of making probable that hold between propositions analogous(in some ways) to the relation of entailment that holds betweenpropositions. On this view, whenP makes probableQ,it is a necessary truth thatP makes probableQ(though that necessary truth is perfectly consistent with the factthat the conjunction ofP andX might not makeprobableQ).

Most classical foundationalists at least implicitly rejected the ideathat the mere obtaining of a probability relation between one’snoninferential evidence thatP and the propositionQone infers from that evidence is sufficient to acquire inferentialjustification or inferential knowledge. Rather, they insisted, onemust be aware of or have access to the probabilistic connection thatobtains between one’s premises and one’s conclusion.Direct acquaintance with facts was proposed to end a potentiallyvicious regress of justification (see section 3), but now the regress looms again in connection with knowledge ofprobabilistic connections. How can one get knowledge of probabilisticconnections between premises and conclusions? If one infers theexistence of the probabilistic connections from the truth of someother different propositionF, then one not only needsjustification for believingF, but, one needs justificationfor believing thatF does indeed make probable that theprobabilistic connection holds! The problem here is essentially theone that has been pointed out by Lewis Carroll (1895), though heapplied the problem to deductive inference. BonJour (2005) cites thisproblem as a reason for taking a direct, nonpropositional grasp oflogical relations as crucial to inferential justification, at leastfor deductive inferences; similarly, Fumerton (2015) argues that, tohalt the regress, the internalist should require a direct awareness ofrelations of making probable between propositions. But are we aware ofsuch relations? The problem seems hopeless if one understandsprobability in terms of frequency, for we do not seem to have anydirect access to such complex, contingent facts as the ratio that oneproposition is true relative to another (logically independent) one.That seems to be the sort of thing one can only know by extensiveobservation, data gathering, or empirical research, and the questionof how we know that some observation makes probable our judgment ofprobability arises all over again. But if one can convince oneselfthat there are real logical relations of making probable holdingbetween propositions, then perhaps the acquaintance theorist cansecure the required knowledge of those connections once again throughacquaintance. Ramsey (1926) famously objected that we do not seem toperceive such relations of making probable, but Hasan (2017) arguesthat these objections are weak, and that there are good reasons tothink we can be directly aware of such relations. This version of theacquaintance theory relies critically on the fundamental concept ofacquaintance in understanding both noninferential and inferentialknowledge. Noninferential knowledge is secured by direct acquaintancewith truth makers. Inferential knowledge is secured by directacquaintance with logical and probabilistic connections between knownpropositions and other propositions.

6. Fallible Noninferentially Justified Beliefs

An acquaintance theory of justification that requires acquaintancewith a proposition’s truth maker in order for the subject to bejustified in believing the proposition may seem to require too much.The requirement rules out the possibility offalsenoninferentially justified belief, and the problem is that there seemto be plausible examples of such beliefs. Suppose that I amexperiencing what seems to be a marginal or border-line case of pain,and that I believe it is an experience of pain. But suppose that, asit turns out, my belief is false; the experience is not a pain but,say, a painless itch.Prima facie, it is plausible that thebelief has some degree (perhaps not very much) of justification, thesame or very close to the degree of justification I might have in the“good” case in which Icorrectly believe that Iam experiencing pain on the basis of an experience of marginal pain.Other cases might involve mistaking hot and cold, mistaking shades ofphenomenal color, mistaking the number of speckles in a region ofone’s visual field, and mistaking the content of one’s ownthoughts. Moreover, even when we restrict our attention totrue noninferentially justified beliefs, it seems plausiblethat the degree of justification can vary, and we need some way ofaccounting for this. Suppose, for example, that I really amexperiencing a marginal case of pain. It is plausible to think that mybelief that I am experiencing pain, while true, is not as justified asthe belief would be if I were in searing pain.

McGrew (1995, 1999) argues that a kind of certainty or infallibility(in his terms, “incorrigibility”) is a necessary featureof empirical foundational beliefs: a belief thatP isempirically foundational only if being justified in believing thatP guarantees its truth. He defends the view that suchfoundations are available and that they are adequate to yieldknowledge of the external world. Other classical foundationalists wantto allow for the possibility offalse foundational beliefs.(See Fumerton 1995: 77; BonJour 2003: 73–74; and Fales 1996:174–80. For a critique of acquaintance theorists’ attemptsto accommodate fallibility at the foundations, see Huemer 2007, Poston2010, and Tucker 2016. For replies to some of these critiques, seeFumerton 2010 and 2016, Hasan 2013, and Stoutenburg (forthcoming).Stoutenburg nevertheless motivates infalliblism, and provides anaccount of how propositions that moderate foundationalists regard asbasic derive their justification from infallibly knownpropositions.)

Intuitively, we may want to allow that one be justified to some degreeif the fact with which one is actually acquainted corresponds to aproposition that is very similar to the proposition believed (Fumerton1995: 77). This might suggest the following principle:

1. If one is directly aware ofx’s beingF, andF is sufficiently similar toG, then one thereby has atleast some defeasible justification for believing thatx isG.

One apparent problem with this suggestion is that the satisfaction ofthe antecedent does not seem to give the subject a reason to think thebelief is true. The problem is clear if we assume, as acquaintancetheorists generally do, that a belief can be justified for a subjectonly if the proposition believed is made probable by thesubject’s evidence, or by that with which the subject isacquainted. The mere fact that I experience one of these shades failsto make probable, indeed, rules out, that I experience the other, andso gives me no justification for believing that I experience theother. Here’s a second attempt:

2. If one is directly aware ofx’s beingF, butit seems to oneself thatx isG or one is inclined tobelieve thatx isG, then one thereby has at least somedefeasible justification for believing thatx isG.

The problem with this suggestion is that acquaintance or directawareness doesn’t seem to be doing the crucial epistemic work.If the principle is true, why not hold some version of“phenomenal conservativism” in epistemology, the positionthat a propositional awareness—a seeming thatx isG or an inclination to believe thatx isG—is a source of defeasible justification for believingthatx isG? If so, then the acquaintance or directawareness requirement should be dropped from (2) and there would stillbe the justification. Here is perhaps a more promising strategy:

3. If one is directly aware ofx’s beingF, andx’s beingF makes it probable for one that it isG, then one thereby has at least some defeasible justificationfor believing thatx isG.

We get different versions of the acquaintance approach to falliblebeliefs depending on what is required for something to “makeprobablefor one”. Acquaintance theorists with stronginternalist inclinations are likely to insist that awareness of thefact thatp cannot justify one in believing thatpunless the subject is in some way also aware of the fact’smaking it probable thatp.

Reflection on some examples suggests the following problem with thisprinciple. An experience’s being a mere itch does not make itprobable that it is a pain, for its being a mere itch rules out itsbeing a pain; and an experience’s being indeterminately eitheran itch or a pain does not make it probable that it is a pain, for itmight just as probably be an itch. Or suppose that I am directly awareof a phenomenally red patch in my visual field, and on the basis ofthis I form the false belief that it is, say, pink; or that I amdirectly aware of a determinate shade red₁, but I form thefalse belief that the patch is red₂. Again, principle (3)does not apply: something’s being red cannot make it probablethat it is pink, for there are many other shades of red;something’s being red₁ cannot make it probable thatit is red₂, for being one determinate shade rules out beingthe other. (See Huemer 2007 for an argument against (2) and (3) alongthese lines, though one that employs some different examples.)

The problem, however, might not be with principle (3) itself but withthe sorts of features focused on (see Hasan 2013: section 3). Theremay be other features involved in such apparent cases of falliblefoundational justification that do make probable the propositionbelieved. For example, consider the following principle, which is aspecific version of (3):

4. If one is directly aware of some feature’s seeming to beG (or of one’s being inclined to believe that it isG), and its seeming to beG makes it probable for onethat it isG, then one thereby has at least some defeasiblejustification for believing that it isG.

Tucker (2016) presents a dilemma for this proposal: Either therelevant making probable relation is contingent, or it is necessary.If it is contingent, then the justification will be inferential, andso the principle can’t account for misleading noninferentialjustification. If it is necessary, then (like (2)), the principle hastoo much in common with phenomenal conservatism to be attractive fromthe point of view of classical foundationalism. A plausible replywould grasp the second horn: Unlike (2), this does not threaten tocollapse to conservatism, since it still requires acquaintance withsomething epistemically relevant to the targetproposition—acquaintance with a probability maker (and perhapsalso, for those with strong internalist inclinations, acquaintancewith the relation of making probable). If the view still has somethingin common with phenomenal conservatism, that might be a point in itsfavor: it can help capture what the phenomenal conservatism seems toget right without accepting it.

Moser (1989) seems to accept a view along these lines, though he wouldput the fundamental principle in explanatory terms, roughly asfollows:

5. If one is directly aware ofx’s beingF, andy’s beingG is the best explanation for one ofx’s beingF, then one thereby has at least somedefeasible justification for believing thaty isG.

So, for example, if one is directly aware of the appearance of a bluebook, and such an appearance is best explained for one by the presenceof an actual blue book, then one has some justification for believingthat a blue book is present. For Moser, physical objectappearances may be given even though physical objects cannot,and these appearances may justify beliefs about physical objectswithout requiring beliefs about appearances. Though Moser does notdiscuss this explicitly, perhaps beliefs regarding our own experiencescan be justified in a similar way. If an appearance of pain can begiven to me despite the fact that I am not in pain, and the appearancemakes probable or is best explained by the fact that I am actuallyexperiencing pain, then perhaps I have some justification forbelieving that I am in pain. Moser thus aims to defend a form offoundationalism that is classical in its commitment to acquaintance orthe given, and yet “moderate” not only in holding thatsome noninferentially justified beliefs can be false, but also thatsome external world beliefs can be noninferentially justified. A greatdeal depends, of course, on whether a plausible account of theseseemings or appearances can be given, and whether a strong enough casecan be made for the claim that the truth of the relevant propositionsdo best explain the appearances (see Moser 1989: 158–165, for adefense of the latter for external-world beliefs).

Others who accept something along the lines of (3) or (4) seem tofocus on different features. According to Fales (1996: 175), whilesomething’s being given to one is not a matter of degree, the“transparency” of the given is a matter of degree, and canitself be given. When one is thinking that some given experience oritemx isG, and one is directly aware of the uncertainor not-fully-transparent character of one’s awareness, this canmake it merely probable for one thatx isG. Fumerton(2016: 242) appeals to the controversial idea that correspondence cancome in degrees. For example, one can be aware of a shade of colorthat is closer to the orange part of the color continuum but stillcorresponds relatively well to the thought that it is red; as thecorrespondence gets weaker, the justification one has for the beliefalso gets weaker.

Accommodating fallible foundations complicates some aspects of thetraditional view introduced above. First, it no longer seems thatRussell and Price’s criterion that is reminiscent of the methodof doubt is a very good method for determining what one is acquaintedwith, for there will be some objects of acquaintance that aresusceptible to some degree of doubt. However, the method of doubtmight remain useful as a guide to thesort of thing withwhich one can be acquainted: for any physical object, I can conceiveof a case in which any justification I have for believing that itexists is just as it is now, and yet there is no such object, andnothing remotely like it, in my vicinity. Second, we said above thatnoninferential knowledge is secured by acquaintance with truth makers,while inferential knowledge is secured by acquaintance with logicaland probabilistic connections between the propositions known and whatone infers from those propositions. One natural way for theacquaintance theorist to accommodate fallible foundations is to saythatp is noninferentially justified for one only if one isdirectly aware of somefact that either makes trueormakes probable for one thatp; if the subject’sjustification for believing thatp depends on one’sjustification for some otherproposition(s) then thejustification is inferential.

Those who do find it plausible that they can be directly aware ofrelations of correspondence between propositions and facts, and whoaccept some internalist requirement to the effect that one must beaware of the relevance of some fact to the truth of a proposition inorder for that proposition to be justified for one, may be inclined togo a bit further and accept the possibility of acquaintance with otherlogical or probabilistic relations between propositional andnonpropositional items. As we saw above in discussing inferentialknowledge, some acquaintance theorists already accept that we can haveacquaintance with entailment relations and, more controversially,epistemic probability relations between propositions. If we can beaware of similar relations, at the foundational level, between somepropositions and facts with which we are acquainted, this mightsignificantly extend the sorts of foundational beliefs satisfyingstrong internalist requirements. To give just a few simple examples,suppose that I am directly aware of a red triangle in my visual field,and also aware of a relation of logical exclusion or incompatibility(or, if you like, non-correspondence) between the figure’s beinga red triangle and the proposition that it is green, that it is acircle, or that it has five sides. If acquaintance with correspondenceis a source of noninferential justification, then perhaps acquaintancewith these relations of incompatibility can be a source ofnoninferential justification for disbelieving these propositions, orfor believing their negations—believing that the figure is notgreen, that it is not a circle, and that it is not five-sidedrespectively. According to Moser (1989), we can also be directly awareof probabilistic or explanatory relations between propositions andnonpropositional items—e.g., between the proposition that thereis a blue book here, and the given appearance of a blue book (though,as already mentioned insection 3.1, he seems to take this as a requirement for doxastic as opposed topropositional justification).

7. Criticisms

Many objections and concerns have been raised against the acquaintanceapproach. We here discuss three main ones: the Sellarsian Dilemma,Sosa’s problem of the speckled hen, and the threat ofskepticism.

7.1 The Sellarsian Dilemma

In developing the view, we have already responded to one of its mostcommon criticisms. As was noted above, it has been argued (mostfamously by Sellars 1963) that even if there were such a thing asacquaintance with individuals, properties, or facts, that relationwouldn’t give one knowledge oftruths. The observationis correct (since acquaintance with something does not amount to ajudgment, let alone a true judgment, about it), but it is irrelevantto the more sophisticated view according to which the acquaintancewith the relevant fact is only aconstituent of the ground ofpropositional knowledge. As we have seen (section 3), acquaintance theorists typically add conditions that make the factwith which one is acquainted directly relevant to the truth of somethought or belief—e.g., by requiring awareness of thecorrespondence or fit (or perhaps some other relation) between thethought and the fact, or by requiring that the fact constitute part ofthe content of the belief.

These sophisticated views also seem capable of handling a closelyrelated, influential objection. Inspired by Sellars, BonJour (1978,1985) presented the following dilemma for any foundationalist viewthat takes one’s justification to consist in or dependessentially on some sort of awareness, acquaintance, or apprehension.(See also, Sellars 1963: Part I, 1975; Davidson 1983; McDowell 1994;and Williams 2005.) Is the awareness or acquaintance that is thealleged source of noninferential justification propositional orconceptual? That is, does it involve the acceptance of a propositionor thought, or at least the categorization of some sensory item or theapplication of some concept to experience? If, on the one hand, theacquaintance or awareness is propositional or conceptual in this way,then while such acts or episodes of awareness seem capable, inprinciple, of justifying other beliefs, they would surely need to bejustified themselves. The episode of awareness would involve somethinglike the acceptance of a proposition, and such an attitude clearlyneeds justification if it is to justify anything else. But then, theallegedly foundational belief is not foundational after all. If, onthe other hand, we can regard direct awareness as nonpropositional andnonconceptual, then while these acts or states of awareness do notrequire or even admit of justification—for simply being aware ofsomething is a mental state that is clearly neither justified norunjustified—they also don’t seem capable on their own ofproviding a reason or justification for propositional items likebeliefs. Therefore, the classical foundationalist’s acquaintanceor direct awareness cannot serve as a foundational source of knowledgeor justified belief.

Most sophisticated versions of classical foundationalism are perhapsbest understood as grasping the nonpropositional horn of the dilemma,since acquaintance is a nonpropositional form of awareness. Fumerton(1995: 75) replies that while acquaintance itself is nonpropositional,that does not rule out that propositions or thoughts are objects ofacquaintance or constituents of objects of acquaintance, and if one isacquainted with a relation of correspondence between a thought and afact, that would seem to provide all the justification one could needor want. As we have seen, BonJour (2003) gives a similar reply thatappeals to direct awareness of some fact and a direct recognition ofthe fit between the fact and the proposition believed. He regards thisrecognition as judgmental or propositional, and that may lead some topush the propositional horn again: we need something further tojustify the judgment of fit, and so the regress of justification hasnot yet come to an end. (For a response, see BonJour 2003: 193. Forsome critical discussion, see Bergmann 2006: Ch. 2.) McGrew, Chalmers,and others who adopt the demonstrative or phenomenal concept strategymight reply that at least in the case of demonstratively formedbeliefs the relevance of the truth maker to the proposition believedis transparent and guaranteed by the manner in which the belief isformed: acquaintance simply picks out some feature of experience andtakes it up into the content of a belief or judgment that asserts thatthe feature exists or is instantiated.

7.2 The Problem of the Speckled Hen

Recently, Sosa (2003a,b), Poston (2007) and Markie (2009) have raisedthe problem of the speckled hen in objection to the acquaintancetheorist’s conception of noninferential justification. Thespeckled hen presents an appearance of, say, 48 speckles. One is, theyassume, directly acquainted with one’s visual field replete withthe 48 speckles. Yet unless one has counted the speckles, one isunlikely to have justification for believing that one’s visualfield contains the 48 speckles. Even if one guesses correctly thenumber of speckles in the field, one’s guess hardly counts as ajustified belief. Direct acquaintance with truthmakers for one’sbelief is, then, clearly not sufficient for noninferentialjustification.

There are a number of responses available to the acquaintance theorist(see BonJour 2003 and Fumerton 2005). It need not be part of theacquaintance theorist’s view that in being directly acquaintedwith an experience one is directly acquainted with all aspects of theexperience. One might be directly acquainted with the fact that one isbeing appeared to many-speckledly without being acquainted with thefact that one is appeared to 48-speckledly. Think, for example, abouthow you can be aware of a car’s having a dark color withoutbeing aware of its having a determinate shade. Some may deny thatcases like the latter are clearly possible, for is one not aware ofthe specific shade as well, even if one does not have a term orconcept for it? Indeed, as we have seen, some acquaintance theoristshold that one is acquainted with or directly aware of all intrinsicsensory or phenomenal features of one’s experience, includingspecific shades of color. However, they require in addition that thesubjectattend to the relevant feature or fact, and so theyare still able to distinguish between a selective, attentive awarenessand a more minimal consciousness or peripheral awareness. They mayattempt in this way to accommodate the intuition that we are consciousof or aware of a great deal more than we attend to or notice, whileinsisting that this attention or noticing is a nonjudgmental awarenessthat secures its object—a form of acquaintance in our sense.(See for example, BonJour 2003: 192 and Chalmers 2010: 88, n. 5. Seesection 2 above for some elaboration.) On this view, one might attend toone’s being appeared to many-speckledly without attending toone’s being appeared to 48-speckledly.

One might also respond that even if one is acquainted with one’sbeing appeared to 48-speckledly, one might fail either to have theright sort of thought or fail to be directly aware of a correspondencerelation holding between this fact and the corresponding thought. Itmay be that we do not have the simple concepts for such properties,and so cannot compare them directly with the contents of experience.Perhaps, when one thinks of something’s having 48 speckles, onecan think of it, as Russell might say,only bydescription (e.g., that number that is picked out by thenumeral ‘48’, or by some other description) such thatone’s having the thought does not involve acquaintance with theproperty of being 48-speckled. A Russellian about the nature ofthoughts (see section 4) might say that we cannot be directly aware of the property(universal) of being 48-speckled, and so cannot compare that propertydirectly with what is experienced. Alternatively, some might say thatwhile we have phenomenal concepts for color and perhaps some basicshapes and numbers, we (most of us anyway) lack the phenomenal conceptof being 48-speckled (Feldman 2004). On such a view, if my thoughtthat I am appeared to 48-speckledly does not involve such Russellianor phenomenal concepts, but rather involves descriptive or complexcontents, then it is no surprise that I am not foundationallyjustified in believing that I am appeared to 48-speckledly.

As long as one has an account of why one of the conditions fornoninferential justification fails, one is in a position to respond tothe objection.

7.3 The Threat of Skepticism

Although it is not always offered explicitly as an argument, many nodoubt reject the acquaintance theorist’s account of bothnoninferential and inferential knowledge out of fear that the accountwill inevitably lead to a radical skepticism. If knowledge byacquaintance is restricted to belief in propositions where one’sepistemic situation precludes the possibility of error, critics mightwell be right in suggesting that we have a tiny body of knowledgesecured by direct acquaintance. The rest of what we know orjustifiably believe must be secured by inference, and the fear is thatwe simply don’t have anything like the inferential resources toget from such a narrow base to commonsense beliefs about the worldaround us. Even if we allow for some fallible foundational beliefs, asmany contemporary acquaintance theorists do (seesection 6), one might still worry that the class of facts with which we areacquainted do not constitute a very impressive base. How legitimatethat fear is depends very much on the analysis of inferentialknowledge one accepts. If one requires access to probabilistic orexplanatory connections as a condition for inferential knowledge, thenunless one can be acquainted with such connections holding betweenpropositions, skepticism does, indeed, loom on the horizon. A numberof acquaintance theorists are more optimistic, however, thatskepticism regarding the external world can be avoided (see McGrew1995; Moser 1989; BonJour 2003; and Hasan 2018).

Even should it be true that the classical foundationalist has a viewthat invites skepticism, it should, perhaps, be an open question as towhether that constitutes a legitimate objection to the view. Classicalfoundationalists are likely to deny that skeptical implications of atheory of justification generally or automatically discredit it. Evenif we don’t have good grounds for many of our beliefs, includingbeliefs regarding the external world, it may be that we need goodgrounds to be justified and we do not have them. The skepticalimplication may be correct rather than objectionable.

8. Concluding Remarks

Many honestly claim that they are not sure what acquaintance is. Ifasked what reason they have for thinking that there is such a thing asacquaintance, some acquaintance theorists would reply that they areacquainted with their being acquainted with things, or directly awareof their being directly aware (Russell 1912: Ch. 5; Fumerton 1995:77). Moser provides a useful analogy:

Compare the parallel situation where one is so absorbed in what ishappening on the movie screen that one is completely unaware ofone’s watching a movie. (1989: 78)

Becoming aware of one’s watching a movie is analogous tobecoming acquainted with one’s being acquainted with pain, orbecoming acquainted with one’s being acquainted with a shade ofred. However, if the analogy is apt, the opponent might see it as areason to doubt that the acquaintance relation is really there, foronce we reflect on whether we are watching a movie it is almost alwayseasy to determine whether we are, but the opponent has no easy timefinding any such relation as acquaintance or direct awareness. Ofcourse, the movie analogy is just that—an analogy. As alreadydiscussed insection 2, from the acquaintance theorist’s perspective, such analogiesand metaphors are bound to be misleading in some respects. It might bemore fruitful to direct one’s attention to it by describing itin some (hopefully) revealing way, as we did insection 2: acquaintance is that relation the subject had to pain before beingengrossed in the conversation, the relation that ceased during theconversation, and that began again shortly thereafter.

Many do find it intuitive andprima facie plausible that theyare acquainted with or directly aware of at least experiential statesand their features, and that this direct awareness is a fundamentalsource of knowledge. Still, some will claim not to find such arelation. It’s not clear how damaging this is to the proponentsof acquaintance. The fact that doubts and disagreements can ariseregarding acquaintance or the given should not be too puzzling sincenot everything about the nature of the given is itself given, and, asDescartes observed long ago, one can easily raise doubts regardingwhat one can see most clearly and distinctly, at least while one isnot attending directly to the appropriate ground or insight. To beclear, this is not to say that those who doubt the existence ofacquaintance must not be trying to attend to it, or even that they aresomehow unable to find it; it would be more appropriate to say thatthey don’t realize that it is acquaintance that they have found,or that this realization is fleeting, unstable, or easy to dismiss asmerely apparent. Some opponents may actually accept that somethinglike acquaintance exists but doubt that it can provide much, if any,justification for our beliefs; in denying that they have foundanything like acquaintance, it may be that they mean only to deny thatthey have found a relation of acquaintancethat can make asignificant difference to the epistemic justification of ourbeliefs.

But what of those who deny that they ever find anything like arelation of acquaintance when they introspect or go looking for it?Shouldn’t such denials raise serious doubts regardingacquaintance? To determine the impact of such denials on theacquaintance theory, it will help to reflect more carefully on how weshould understand them. If we understand the opponents as claimingthat they are not directly aware of being directly aware of anything,or that they are not acquainted with being acquainted with anything,then they would be presupposing the existence of that which they claimnot to find. It seems that we ought, instead, to take them as claimingthat they simply do not understand what acquaintance is, or what theacquaintance theorist means by ‘acquaintance,’ even afterattempting to follow the acquaintance theorist’s attempts tolead us to grasp or understand it. Dialectically, there seems to be noway for the acquaintance theorist to reject this opposing positionwithout begging the question. However, this does not show that theacquaintance theory is false or unjustified. Objections to the veryintelligibility of critical philosophical concepts (concepts of self,universals, causation, free will, matter, etc.) are hardly rare inphilosophy, and philosophers do not abandon their positions in theface of such disagreements. The fact of disagreement betweenphilosophers on fundamental matters may lead to difficulties.Disagreement between those who seem to be our intellectual peers orequals may suggest that we should lower our confidence in our ownviews, perhaps even drastically lower our confidence. But these arenot difficulties that only the acquaintance theory confronts. So, tothe extent that there is an objection or problem with the fact thatsome deny that there is such a thing as acquaintance, a similarproblem seems to afflict most any other philosophical theory.

The acquaintance theorists are aware that their claim to beingacquainted with acquaintance is unlikely to be of much help to thosewho claim not to understand what acquaintance is, and may point outthat there are other, dialectical considerations in favor of theirview (see Fumerton 1995: 77; Chalmers 2010: 287; and Taylor 2015). Weend by summarizing a number of such considerations. While theseconsiderations are controversial, they suggest that acquaintancetheories deserve more serious attention than they have recentlyreceived. Most of these have already been covered above. First,acquaintance theorists have defended sophisticated accounts ofnoninferentially justified belief, and offered responses to classicalarguments against the possibility of such beliefs, like the Sellarsiandilemma. Second, a view that accepts the possibility of acquaintancewith universals seems able to explain not only how knowledge ispossible, but also how thought itself is possible, and how a thoughtcan beabout something else. Third, the acquaintance theoristwho accepts acquaintance with complex universals is in a position toprovide an account of our knowledge of necessary truths. Fourth, thosewho accept acquaintance with logical or probability relations betweenpropositions can give a unified treatment of foundational andnonfoundational knowledge—a unified treatment of knowledge byacquaintance and knowledge by description—and are not asvulnerable to the threat of skepticism. Fifth, the sophisticatedacquaintance theory seems to accommodate two constraints on epistemicjustification that many find intuitive (though not everyone accepts;many accounts end up rejecting one or the other): justification istruth-conducive, since it requires acquaintance with factsthat make true (or at least make probable) our beliefs; andjustification isinternal in the sense that the subject has asecure perspective on the truth, or possesses a kind of assurance ofthe truth (or probability) via acquaintance with truth-making andprobability-making relations.

Opponents of the theory may seek acquaintance with such relations orentities without finding it, or at least, without realizing that it isacquaintance that they have found. While acquaintance theorists arelikely to take phenomenological considerations seriously, they mayplausibly argue, first, that it is far from obvious that we arenot acquainted with such entities as those just mentioned(indeed, many have found it difficult to deny that we can sometimes,in very simple cases at least, just “see” the entailmentrelation between propositions), and second, that the fact that otherphilosophers disagree about this does not raise a problem specific tothe acquaintance theory. Moreover, the significant theoreticaladvantages gained may more than compensate for any lack ofphenomenological obviousness.

To summarize: Russell’s distinction between knowledge byacquaintance and knowledge by description is arguably best understoodas a distinction between foundational knowledge of truths acquired byacquaintance and nonfoundational knowledge of truths that depend,ultimately, on foundational knowledge. Acquaintance is a direct,nonjudgmental and nonconceptual form of awareness that he took to becrucial for both forms of knowledge. Following Russell, some appeal toacquaintance with particular facts to account for the possibility offoundational empirical knowledge; some appeal to acquaintance withuniversals to account for the possibility of thought itself; someappeal to acquaintance with complex universals to account of thepossibility of foundationala priori knowledge; and someappeal to acquaintance with logical and probabilistic relations toaccount for the possibility of nonfoundational knowledge or“knowledge by description.” Thus, for Russell and manyother acquaintance theorists, even “knowledge bydescription” depends on acquaintance, and in more than one way.Recently, more sophisticated forms of the acquaintance theory havebeen developed, and responses to central objections offered. Moreover,some philosophers of mind have appealed to acquaintance to eitherdefend, or critique, the knowledge argument for dualism. In light ofall this, one can expect the relation of acquaintance and thedistinction between knowledge by acquaintance and knowledge bydescription to remain at the center of a number of debates inepistemology and the philosophy of mind.

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a priori justification and knowledge |justification, epistemic: foundationalist theories of |probability, interpretations of |qualia: knowledge argument |Russell, Bertrand |self-knowledge |sense data

Acknowledgments

Thanks to an anonymous reviewer for very helpful comments on earlierdrafts.