Spinoza’s views on necessity and possibility, which he claimedwere the “principal foundation” of hisEthics(Ep75), have been less than well received by his readers, to put itmildly. From Spinoza’s contemporaries to our own, readers of theEthics have denounced Spinoza’s views on modality asmetaphysically confused at best, ethically nihilistic at worst.^[1] However, expressing matters this way implies that there is aconsensus about Spinoza’s metaphysics of modality, withinterpreters differing only to the extent to which they distancethemselves from his outrageous position. A cursory reading of certainpassages of theEthics supports the belief that, if Spinozais clear anywhere, it is surely in his views of necessity andcontingency. After all, this is the philosopher who claims that“in nature there is nothing contingent, but all things have beendetermined from the necessity of the divine nature to exist andproduce an effect in a certain way” (Ip29) and that“things could have been produced by God in no other way, and inno other order than they have been produced” (Ip33). Passagessuch as these suggest that Spinoza was a necessitarian, according towhom falsity and impossibility are co-extensive. The actual world, wemight now say, is the only possible world. Eventscould not,in the strongest sense of that expression, have gone any differentlythan they in fact have gone.

And yet, such a picture of the interpretive landscape would be quitemisleading. Spinoza studies have seen a renaissance of interest in hisviews on modality, spawning in recent years many articles and chaptersdevoted to his modal views. From this boon of research and interest(relative to Spinoza studies), considerable disagreement has emergedabout Spinoza’s modal commitments. Much of this disagreementstems from larger interpretive disagreements about Spinoza’smetaphysics. By examining Spinoza’s views on modality, we willalso explore several of his most central metaphysical views.

After a brief introduction, this entry begins with Spinoza’sviews on the distribution of modal properties (section 2). Withrespect tosubstances (2.1), Spinoza claims that everypossible substance necessarily exists. Spinoza’s argument forthis conclusion is part of his larger argument for substancemonism—the view that only one substance exists, God.Spinoza’s view about the modal status ofmodes, hisother main ontological category, is far more controversial (2.2).Explaining this controversy leads into the heart of Spinoza’smetaphysics and involves his views on causation, inherence, God,ontological plenitude and the principle of sufficient reason. Althoughthe question of whether Spinoza was a necessitarian is the predominanttopic of discussion in the recent secondary literature onSpinoza’s modal views, Spinoza also sketches interestingaccounts of the nature of modality (section 3) and the ground ofmodality (section 4) that shed fresh light on his modal commitments.Though understudied by recent interpreters, these topics were ofinterest to Spinoza’s peers and remain vibrant researchquestions in contemporary metaphysics of modality.

• 1. The Distribution of Modality
  • 1.1 Substances
  • 1.2 Modes
    • 1.2.1 The Modality of Modes: An Overview
    • 1.2.2 Infinite modes
    • 1.2.3 Finite modes: A first pass
    • 1.2.4 The problem of the gap
    • 1.2.5 Finite modes: a second pass
• 2. The Nature of Modality
  • 2.1 Necessitarianism Vindicated
  • 2.2 Non-necessitarianism also vindicated
• 3. The Ground of Modality
• Bibliography
• Academic Tools
• Other Internet Resources
• Related Entries

1. The Distribution of Modality

Spinoza’s list of the basic types of existing things isexceedingly short: substances and modes (Ip4d).^[2] Spinoza gives two extremely different, but equally striking accountsof how many tokens exist under each of these two basic types. There isonly one existing substance, God, and there are infinitely many modes.Without yet unpacking these claims, we might ask Spinoza, “Butcould there have beenmore substances orfewer modesthan there in fact are?” Or, keeping the number of tokens fixed,“Could there have been adifferent substance ordifferent modes than the ones that in fact exist?”Surprisingly, Spinoza seems inclined to answer “no” tothese questions. If so, then Spinoza thinks the actual world is theonly possible world. This is the position ofnecessitarianism, a belief that few in the history of Westernphilosophy have explicitly embraced. And for good reason — onthe face of it, necessaritianism is highly counterintuitive. Surelythe world could have gone slightly differently than it has gone.Couldn’t the Allies have lost WWII? Couldn’t a leaf havelanded an eighth of a centimeter farther to the right than it in factlanded? Similarly, surely the world could have contained differentindividuals in different numbers than it in fact contains.Couldn’t Leibniz have had a sister or not been born at all?

Spinoza was aware of how deeply against the grain of common sense thetruth of necessitarianism would run. If he nonetheless believed in itstruth, he must have thought he had very compelling reasons for doingso. What might such reasons be? We will begin with substancenecessitarianism (2.1) and then turn to the necessity of modes (2.2).Although the case for interpreting Spinoza as a mode necessitarian isstrong, there are also Spinoza-friendly reasons for resisting such areading. Seeing this tension will lead us into the middle of aninterpretive controversy that has ramifications for understanding manyof Spinoza’s other central metaphysical views. (In section 2, wewill undercover one possible way of reconciling Spinoza’s drivetowards necessitarianism with what might have been equally importantreasons for avoiding it.)

1.1 Substances

In the case of substances, Spinoza claims that every existingsubstance necessarily exists (Ip7d). No existing substance could havefailed to exist. He also claims that only one substance, God, actuallyexists and that only this one substancecould have existed(Ip14). Putting these claims together, Spinoza believes that everypossible substance necessarily exists. Since God is the only possiblesubstance, it is impossible for any other substance besides God toexist.

Spinoza’s argument for these conclusions can be divided into twomajor stages:

1. Every possible substance necessarily exists.
2. God is the only possible substance.

Let us consider Spinoza’s reasoning for each of these steps inturn, as doing so will help us understand some of Spinoza’s mostimportant and basic metaphysical commitments.

In arguing for (1), Spinoza relies on two implicit and relatedpremises. One is theprinciple of sufficient reason (PSR) and the other involves his account of causation. Put roughly,the PSR states that every fact has a reason for obtaining; in sloganform,there are no brute facts. Most relevantly for ourpurposes, if something existed for no reason at all, the fact that itexists would be inexplicable, a violation for the PSR. And forparallel reasons, if something did not exist and there was no reasonfor its non-existence, the fact of its non-existence would also be aviolation of the PSR. As Spinoza puts it, “For each thing theremust be assigned a cause or reason, both for its existence [if itexists] and for its non-existence [if it does not exist]. For example,if a triangle exists, there must be a reason or cause why it exists;but if it does not exist, there must also be a reason or cause whichprevents it from existing, or which takes its existence away”(Ip11d). Thus, according to the PSR, there must be sufficient reasonswhy each existing substance exists and also sufficient reasons whynon-existing substances do not exist.

The second implicit premise of Spinoza’s argument for the claimthat all possible substances necessarily exist is thatcausesprovide (or just are) necessary and sufficient explanatory reasons.This idea appears in the previously quoted passage in which Spinozaclaims that citing a “cause or reason” suffices forexplaining facts about the existence and non-existence of a triangularobject. Applied to the case of substance, the sufficient reason forwhy a substance exists is supplied by the causes of thatsubstance.

Why does Spinoza think that an account of an object’s causesexplains that object’s existence? His most revealing answertraces back to the PSR as well. Because facts about the nature ofcausation are facts, by the PSR, facts about causation requireexplanation too. In a case in whichx causesy, thePSR demands an explanation of what it is in virtue of which the causalrelation betweenx andy obtains. Although one maytry to answer this question by appealing to other causes (say,z’s causingx to causey), the PSRalso demands an account of what it is in virtue of whichxandy arecausally related, as opposed to beingmerely sequentially ordered (or an account of why mere sequentialordering is sufficient for causal relatedness). That is, the PSRapplies not only to facts about existence, but also to facts aboutrelations between existents. (This point will be extremely importantfor correctly understanding Spinoza’s modal theory in section 2below.) The PSR asks not only for an explanation of the fact thatx causesy in terms of prior first-order causes, butalso for an explanation of why there is acausal relation ofdependence betweenx andy and why it is not someother kind of relation. As it would not get us very far to answer byappealing to yet further first-order causal relations, the PSR isreally demanding an account of causation itself. Causation, if the PSRis true, cannot be a primitive metaphysical relation. So, to echo aquestion that lingers today, just what is causation? (For more on thecontemporary discussion, see the entry on themetaphysics of causation. For more on the PSR and causation, see Della Rocca (2010)).

Unsurprisingly, Spinoza does not treat causation as a metaphysicalprimitive. Instead, he provides an account of causation in terms ofsomething else. In Id1, Spinoza defines self-causation (causasui) as “that whose essence involves existence or[sive] that whose nature cannot be conceived except asexisting.” (Spinoza’ssive should not be read ina disjunctive sense, nor is it usually stating a mere equivalence.What follows the “or” is often a fuller account of whatprecedes it. Think of it as an “or better yet…”)Expanding his definition to cover causation in general,Spinoza’s idea is that causation is a matter of“involvement” or conceptual connection. Ifxcausesy, this fact obtains in virtue of a conceptualconnection between the concept ofx and the concept ofy.^[3] Spinoza frequently suggests that theconceiving throughrelation is the paradigm of explanation (e.g., Ia5, IIp5, IIp7s). Ifso, then we can understand why Spinoza thinks causes serve assufficient explanatory reasons for facts about existence. If causalrelations are conceptual relations, and if conceptual relations areparadigms of explanation, then to give an account of an object’sexistence in terms of its causes is to explain the fact that it existsin just the way the PSR demands.

Let us apply this point to the case of substances. Spinoza reasonsthat existing substances exist in virtue of having causes that bringabout and explain their existence, and non-existing substances do notexist in virtue of causes that prevent their existence and explaintheir non-existence (Ip14). According to Spinoza’s account ofcausation, this means that existing substances exist in virtue ofconceptual relations to whatever explains their existence, and,similarly, conceptual relations explain the non-existence ofnon-existing substances. What causes or explains the existence ornon-existence of a substance?

Spinoza argues that substances are conceptually, and hence causally,isolated from one another (Ip2–Ip5). He infers from this thatsubstances cannot be caused to exist or be prevented from existing byany other substance (Ip6). But since all existing substances mustnonetheless have causes and reasons for their existence, the fact thata substance exists must be explained entirely by the substance itself.That is, all existing substances must be self-caused and henceself-explained (Ip7). For parallel reasons, the non-existence of anon-existing substance must be explained solely through facts aboutthe non-existing substance. The concepts of non-existing substancesmust include the explanation for their own non-existence. What aboutthe concept of a non-existing substance could explain thatsubstance’s non-existence? Spinoza’s answer: aself-contradiction. Non-existing substances do not exist for the samereason that squared circles do not exist in Euclidean space: they areconceptually impossible (Ip11d). From the fact of non-existence plusthe PSR, Spinoza concludes that non-existing substances do not existbecause it is impossible for them to exist. They cannot causethemselves to exist because their very concepts contain acontradiction, and facts about causation track facts about conceptualinvolvement and explanation.

So, returning to our opening questions, could there have been moresubstances than there in fact are? Spinoza’s answer is“no,” which means that there are nomerelypossible substances. A substance either exists or its existenceis impossible. Could an existing substance have failed to exist?Again, Spinoza’s answer is “no,” since the onlyavailable explanatory basis for its possible non-existence would befacts about the substance itself. But if an existing substance iscompletely causally isolated, what could bring about itsnon-existence? Only itself, Spinoza answers, which would amountto the concept of that substance containing an internal contradictionthat would prevent such a substance from existing in the first place(Ip7). Spinoza even denies that a substance could exist for acertain length of time and then go out of existence, since thatwould imply that it caused its own self-destruction, a violationof Spinoza’s doctrine that “No thing can be destroyedexcept through an external cause” (IIIp4). In reaching all ofthese conclusions, Spinoza relies on the self-explaining orself-causing nature of substances and the explanatory demands of thePSR. Spinoza concludes that for any existing substance, it could nothave failed to exist nor can it cease to exist. Hence, if a substanceexists, it necessarily exists (Ip7d). On the other hand, if asubstance does not exist, its existence is impossible. Combining theseconclusions, we reach (1): every possible substance necessarilyexists.

Here is a sketch of the main steps of this argument:

3. There must be a sufficient reason why each existing substanceexists and a sufficient reason why non-existing substances do notexist [PSR; see Ip11d].
4. Causes provide necessary and sufficient reasons for the existenceand non-existence of substances [nature of causation and PSR; seeIp11d].
5. Substances are causally isolated [Ip6].
6. If a substance exists, it is self-caused [3–5; seeIp7].
7. If a substance is self-caused, its existence is necessary [natureof necessity and self-causation; see Ip7d and Id1].
8. If a substance exists, it necessarily exists [6–7].
9. If a substance does not exist, its non-existence is explainedentirely by facts about the concept of its nature [3–5 andnature of causation; see Ip11d].
10. If facts about the concept of a thing’s nature entirelyexplains its non-existence, then the concept of its nature contains acontradiction [nature of concepts and explanation; see Ip11d].
11. If a substance does not exist, then the concept of its naturecontains a contradiction [9–10].
12. If the concept of a thing’s nature contains a contradiction,then its existence is not possible [intuition; see Ip11d].
13. If a substance does not exist, then its existence is not possible[11–12]

1. Therefore, every possible substance necessarily exists [8 and13].

The second major stage of Spinoza’s argument is to prove thatGod is the only possible substance. We will not here rehearse all thedetails of Spinoza’s argument to this conclusion (fortwo discussions, see Lin 2007 and Della Rocca 2001). Like hisargument for (1), Spinoza’s argument for (2) relies on the PSR.Here is one sketch of Spinoza’s overall argument for (2):

14. At least one substance exists.^[4]
15. The concept of God is the concept of the most real substance withthe most power and greatest reason for existing [Id6, Ip9, andIp11d].
16. The concept of God is internally consistent [assumption].
17. It would be inexplicable if the internally consistent concept ofthe most real substance with the most power and greatest reason forexisting was not instantiated while the concept of a substance withless power and less reason for existing was instantiated [Ip11d].
18. Nothing is inexplicable [PSR].
19. Therefore, the concept of God is instantiated [14–18].
20. Therefore, God necessarily exists [1 and 19].
21. The existence of God and the existence of other substances are notcompossible [20 and Ip5].

2. Therefore, God is the only possible substance [20–21].

Of these steps, premise (16) is the one for which Spinoza offers theleast explicit justification:

Since, then, there can be, outside the divine nature, no reason orcause which takes away the divine existence, the reason [for itsnon-existence] will necessarily have to be in his nature itself, ifindeed he does not exist. That is, his nature would involve acontradiction.But it is absurd to affirm this of a Beingabsolutely infinite and supremely perfect (Ip11d, emphasis mine).

The absurdity Spinoza points to is actually the absurdity of thenon-existence of a beingaccording to whose concept it isinfinite and supremely perfect. But why accept that the concept ofSpinoza’s God is internally consistent? If Spinoza fails tojustify this assumption, his ontological argument would fall victim toLeibniz’s complaint that even if otherwise successful,(pre-Leibnizian) ontological arguments prove only a hypotheticaltruth:if God is a possible substance, then God necessarilyexists. Spinoza’s argument, absent a justification of (16),fails to establish the possibility of God before asserting thenecessity of God’s existence.

Even worse, Spinoza faces an especially thorny problem in justifying(16). For his account of the concept of God in (15) relies oncommitments that even those friendly to theism, such as Descartes,would reject. Spinoza defines God in Id6 as “a substanceconsisting of an infinity of attributes, of which each one expressesan eternal and infinite essence.” Spinoza claims in Ip9, withoutany explicit argument, “The more reality or being each thing[unaquaeque res] has, the more attributes belong toit.” This definition of God and the supporting principle in Ip9were highly controversial. According to Descartes, a substance cannothave more than one (principal) attribute.^[5] To say that the concept of God is the concept of a substance withmultiple (principal) attributes is, in fact, to appeal to aninternally inconsistent concept. So, the objection runs, not only hasSpinoza failed to justify (16), but (15) is outright false.

Spinoza’s defense of (15) would likely be to appeal to theself-containment of each attribute (Della Rocca 2001). Like substance,each attribute is a wholly self-contained and self-sufficient way ofconceiving substance (Ip10). Given such rigid containment, Spinozawould press, how could the fact that a substance has one attributepreclude that substance from having additional attributes? If thereare no explanatory or conceptual relations between the attribute ofthought and the attribute of extension, the fact that a substance isthinking cannot explain why that substance could not also be extended.The lack of a reason forexcluding an attribute is part ofSpinoza’s reason forincluding all possible attributesas attributes of God. However, even if he can defend the rigidself-containment of attributes, Spinoza will also need a positivereason for including them all together as attributes of a singlesubstance.

This brings us back to Ip9 and the other objectionable aspect of (16).Why should perfection or reality and strength of reason to existcorrespond to possessing a greater number of attributes? Spinoza doesnot offer any explicit defense of this correlation. The demonstrationof Ip9 simply refers readers back to the definition of an attribute(see also Ep9). Here is one possible way Spinoza might motivate thecorrelation between number of attributes and perfection / reason forexisting. The principle in Ip9 may be that to the extent to which asingle thing [unaquaeque res] can be expressed by agreater number of attributes, to that extent it is more perfect, andhence is more real (IId6) and has greater reason for existing (Ip11s).Spinoza’s emphatic “unaquaeque” may point to theidea that perfection involvesboth unity and diversity. Tothe degree to which one and the same thing can sustain a greatervariety of expressions of it, to that extent it is more perfect. Themaximal perfection and reality of God, on this account, is partlyconstituted by the fact that God’s self-identity is compatiblewith a plentitude of incommensurable expressions – infinitelymany attributes – of it. This view of metaphysical perfection,one which tries to maximize both identity and diversity, is verysimilar to Leibniz’s account of perfection asharmony,a principle that Leibniz explains as “diversity compensated by identity.”^[6] On this reading, God’s metaphysical perfection for Spinoza isthe perfection of Leibniz’s most harmonious world, theperfection of maintaining both the oneand the many (Newlands2018).

Whether or not Spinoza fully succeeds in defending the consistency ofhis concept of God, the striking modal conclusion he draws from it isclear: “Except God, no substance can be or be conceived”(Ip14). This statement captures Spinoza’s substance monism andhis substance necessitarianism: there is only one possible substance,God, and that substance necessarily exists.

1.2 Modes

Immediately after wrapping up his proof for substance monism in Ip14,Spinoza claims in the next proposition that “Whatever is, is inGod, and nothing can be or be conceived without God” (Ip15). Bythe definition of a mode in Id5, Ip15 implies that everything thatexists other than God is a mode or affection of God. To understand theimport of this claim, it is important to understand what a mode is andwhat is it for a mode to bein a substance, for Spinoza.

A natural way to think about modes is as a certain kind of property.The circular shape of the coin is amode of that coin. Onthis reading, being circular is a state of the coin, a particularizedway that the coin is. Spinoza’s claim that modes are“in” their substances also suggests that modesinhere in substances akin to the way that properties inherein things, and that modes are therefore predicable of substances assubjects of predication. Circularity, we might say, inheres in thecoin andthe coin is circular. Of course, there is anextremely wide range of views about properties and property-bearers(see the entry onproperties), so claiming that modes are akin to properties that inhere insubstances will not answer all questions. But even putting asidequestions about inherence, property instantiation, and predicationrelations, it may seem like Spinoza has made a colossal blunder inIp15. After all, how can a table or human being be anything like aproperty? How can I inhere in something else? What sensewould it make to say of something — a substance — that itisSam Newlandsish in the same sense in which I say of itthat it is round? If there is such a thing as a “categorymistake,” this may seem like an especially clear case of one.^[7]

It would be disappointing if this objection simply assumed from theoutset that (a) objects like tables and human beings are substancesand (b) substances neither inhere in nor are predicable of othersubstances. Spinoza agrees with (b), but he has already arguedpace (a) that there can be only one substance. It would beunfair to grant him that conclusion in Ip14 and then insist uponreading Ip15 that other things still ought to have all the features ofsubstances. (Of course, these intuitive concerns may well providereasons to reconsider Spinoza’s arguments for Ip14.)

Interpreters have tried to make sense of Spinoza’sidentification of everyday objects with modes without presupposing thedenial of his substance monism. One strategy would be to deny thatSpinoza intends anything like property, inherence and predication byhis identification of everyday objects with modes of God. On thisinterpretation, Spinoza’s claims about modes and“in” in Ip15 are really just claims about thecausal dependence of all things on God (Curley 1969).Everyday objects inhere in God in the sense that they depend causallyon God. When Spinoza claims, “Whatever is, is in God,” hereally means only that everything is causally dependent on God, afantastically unremarkable claim in the 17^th century.Indeed, as others have objected (Bennett 1991, Carriero 1995, Melamed2009), this proposal makes Spinoza’s claim in Ip15sounremarkable that it is hard to see why Spinoza went to suchobfuscating lengths to phrase his ontology in terms of modes andinherence in the first place, since he had the categories of efficientcausation and dependent beings at his disposal.

A different strategy (Carriero 1995) preserves the inherence linkbetween modes and properties, but understands Spinoza’s modes asparticularized accidents or, in contemporary terms,tropes(see the entry ontropes). According to this reading, collections of particularized propertiesconstitute everyday objects for Spinoza. Although such bundles oftropes inhere in substance, they are not predicable of substance.Hence, although I inhere in substance, it is not the case thatsubstance is Sam Newlandsish, whatever that may mean. Whereasthe first interpretation explained inherence as nothing but efficientcausation, this reading tries to keep causation and inherenceintensionally (though perhaps not extensionally) distinct metaphysicaldependence relations.

Another, more circuitous option begins with a functional account ofmodes in Spinoza’s ontology. The function of modes, according topassages like Ip25c, is to provide ways of expressing or conceivingthe power of substance. Perhaps Spinoza actually provides ananalysis of inherence in terms of this expressive orconceptual relation, similar to the way in which he provides ananalysis of causation in terms of conceptual connection. Consider, forinstance, Id3, in which Spinoza defines substance as that which is“[a] in itself and [b] is conceived through itself, that is, [c]that whose concept does not require the concept of another thing fromwhich it must be formed” (the brackets are mine). Instead ofleaving inherence as an unprincipled primitive relation ofmetaphysical dependence (pace the PSR), one could read [c] asproviding an analysis ofboth [a] and [b]. One thing inheresin another in virtue of being conceived through it, which, likecausation, is a matter of conceptual involvement. That everydayobjects are modes inhering in and predicated of substance isextensionallyand intensionally equivalent to everydayobjects being conceived through substance. Whereas Curley’sinterpretation tookcausation to be Spinoza’sunderlying account of inherence, this interpretation takesconceptual involvement to be Spinoza’s underlyingaccount of both inherence and causation (for defense, see Newlands2010a; for dissents, see DiPoppa 2013, Melamed 2012 and Laerke2011).

Although we will not try to settle this debate here, differentinterpretations of Spinoza’s category of modes will yielddifferent accounts of his views on the necessity of modes. Forpurposes of ease and neutrality, we will frequently refer to modes as“objects,” which are intended to be a neutral placeholderfor “whatever else exists besides substance.”

1.2.1 The Modality of Modes: An Overview

Earlier, it was noted that Spinoza thinks infinitely manynon-substantial objects exist: “From the necessity of the divinenature there must follow infinitely many things in infinitely manyways, i.e., everything which can fall under an infiniteintellect” (Ip16). Although Spinoza means more by“infinite” than simply “exhaustive,” heclearly intends “exhaustive” as well. How many objects arethere? “As many as there can be together” isSpinoza’s basic reply. That is, Spinoza endorses a principle ofontological plenitude (POP), according to which the greatest number ofcompossible non-substantial objects actually exists. Part ofSpinoza’s motivation for POP may derive from the PSR itself,since if the actual world were sub-maximal, non-existing butintrinsically possible objects would have no reason for not existing,which would be a brute fact. Perhaps it would also be an undesirablebrute fact if (per impossibile) a maximal world with fewerobjects than the actual world existed; what would explain God’srealization of a smaller maximal collection when a larger maximalcollection is possible (see Ip33s2)? In any case, Spinoza’s POPimplies that the number of existing objects is necessarily fixed.

Although this is already quite a strong conclusion, it does not yetrise to the level of full-blown necessitarianism with respect tomodes. There are still at least three possible sources of contingencyfor the maximally full world of modes, each of which would becompatible with POP. Alternative possibility 1 (AP1): There could havebeen a different collection of modes, equal in size to the actuallyexisting collection, but withentirely different members.Alternative possibility 2 (AP2): For some proper subset of thecollection of actually existing modes, there could have been adifferent, equinumerous proper subset of modes instead. Alternativepossibility 3 (AP3): One or more of the actual modes could have haddifferent characteristics than it in fact has.

To illustrate, let the collection of shirts hanging in my closet standfor the collection of modes. Suppose that my closet could not containmore or fewer shirts than it currently contains— my closet is asfull as it can get and I’m the sort of person who could neverhave fewer shirts than the most that can all fit in there together.Still, couldn’t I have had an entirely different butequinumerous collection of shirts (AP1)? Or, keeping some of theshirts fixed, couldn’t I have had a modest blue shirt instead ofthe orange plaid shirt sitting there in the middle (AP2)? Or, keepingall the shirts in the closet fixed, couldn’t the orange plaidshirt have had a single pocket instead of having the two pockets thatit actually has (AP3)?

Necessitarianism requires not only the necessity of thenumber of existents; it demands the necessity of each memberand the necessity of all of its characteristics. Hence, even given POPand Ip16, it remains an open question whether Spinoza wants to denythat there are any alternative possibilities for modes. Am I reallystuck with the exact shirts I’ve got, double-pocketed orangeplaid and all?

To understand why Spinoza might be attracted to mode necessitarianism,we need to consider a few additional details of his ontology of modes.I have been lumping modes together into a single ontological category:everything that is not a substance. But Spinoza sometimesdistinguishes between two types of modes, infinite modes and finitemodes. Unfortunately, Spinoza gives only a very sparse account ofinfinite modes in theEthics, and he makes very few explicittextual references to them outside theEthics.^[8] When Georg Schuller wrote to Spinoza to ask him for examples of thesecurious entities, Spinoza replied with obscure gems like “theface of the whole universe” and “absolutely infiniteintellect” (Ep64). If the best elucidation ofa philosophical doctrine makes reference to “the face ofthe whole universe,” that may be a good sign that the doctrineneeds further development. Unfortunately for Spinoza’s readers,infinite modes appear to do some significant work in his metaphysics,so they cannot simply be ignored if one wants to understandSpinoza’s modal commitments.

1.2.2 Infinite modes

The most salient feature of infinite modes is that they are moredirectly related to substance than finite modes are. Spinoza claimsthat infinite modes follow more or less directly from “theabsolute nature of any of God’s attributes,” whereasfinite modes do not follow from the absolute nature of God’sattributes (see Ip21–22 and Ip28d). According to someinterpreters, understanding this distinction is the key tounderstanding whether or not Spinoza was a full-blownnecessitarian.

At first glance, Spinoza’s picture seems clear enough. (We willcontinue to ignore the complicating role of attributes.) Some modesfollow directly from the absolute nature of substance. Interpretersfrequently call theseimmediate infinite modes (Ip21). Othermodes follow directly from those immediate infinite modes. These arecommonly calledmediate infinite modes (Ip22). There is thena gap of some kind, and on the other side of the gap is the maximallyfull collection of finite modes. Unlike the infinite modes, particularfinite modes do not follow, either directly or indirectly, from theabsolute nature of substance.

The distinction between infinite and finite modes is relevant forSpinoza’s views on modality because of what he says about themodal status of infinite modes. Spinoza reasons that if an objectnecessarily follows from something that necessarily exists, then thatobject also necessarily exists (Ip21). This sounds similar to afamiliar and widely accepted modal distribution axiom: \((\Box p \amp\Box(p \to q)) \to \Box q\). According to this reasoning, if Godnecessarily exists, and if the existence of a mode follows necessarilyfrom the existence and nature of God, then that mode necessarilyexists too. Of course, we need not and should not interpretSpinoza’s following-from relation as the strict logicalentailment of contemporary modal logic. The main point is thatnecessity transfers down the following-from chain, according toSpinoza. Ifx necessarily exists and ifynecessarily follows fromx, theny necessarilyexists too. For ease, one may call this themodal transferprinciple. (Later, we will try to gain a better understanding ofexactly why Spinoza thinks the modal transfer principle works.)

Notice thatboth conjuncts of the modal transfer principlemust be satisfied for it to apply. That is, for the modal transferprinciple to apply to somey, it must be the case that both(i)y follows necessarily fromx and (ii)xexists necessarily. Hence, if God exists necessarily and if theexistence of Bruce Springsteen follows necessarily from God’sexistence, then Springsteen exists necessarily too. Whateverdifferences there may be between a thing that exists necessarily invirtue of its own nature and a thing that exists necessarily in virtueof following from something else that exists necessarily, thatdistinction is whollyinternal to necessity. Differencesbetween external and internal sources of necessity, a difference towhich Spinoza sometimes draws attention (Ip33s), does not entaildifferences intype of necessity or evenstrength ofnecessity, and Spinoza nowhere says that it does.

Spinoza’s modal transfer principle appeals to the relation offollowing-from. To a contemporary reader, this might sound like arelation of logical entailment, but Spinoza clearly understands it tobe some kind of causal relation (e.g., Ip16c, Ip28d). This means thatSpinoza’s following-from relation shares the features of hiscausal relations, including the fact that causal relations involvenecessary connections between relata (Ia3). That is, ifyfollows fromx, theny necessarily follows fromx. Furthermore, Spinoza claims thatevery modefollows from something else (Ip16 and Ip36). Therefore, every modenecessarily follows from something else, in which case condition (i)of the modal transfer principle is satisfied for every mode. This doesnot yet entail necessitarianism, however, for we still need todetermine whether condition (ii) is universally satisfied as well.Each mode necessarily follows from something else, but does what itfollows from exist necessarily?

In the case of existinginfinite modes, Spinoza’sanswer is clearly affirmative. In Ip22, Spinoza claims that so-called“immediate” infinite modes follow from something thatexists necessarily, namely substance. Therefore, by the modal transferprinciple, every existing immediate infinite mode exists necessarily.Furthermore, Spinoza claims that every so-called “mediate”infinite mode follows from something that exists necessarily (namely,an immediate infinite mode), so every mediate infinite mode existsnecessarily as well (Ip23). In short, because there is a chain ofnecessary dependence stretching from substance to every existinginfinite mode, every existing infinite mode exists necessarily.

Once again, even this strong modal conclusion is not equivalent tofull-blown necessitarianism regarding infinite modes. Even if everyexisting infinite mode necessarily exists, could there havebeen other infinite modes as well? While there may not be any texts inwhich Spinoza explicitly rules this out, it is easy to imagine what hewould say. Non-actual infinite modes do not exist necessarily, or elsethey would actually exist, on the plausible assumption that necessityentails actuality \((\Box p \to p).\) So, for reductio, consider anon-actual possible world, \(w^*\), that containsSophia, one of these extra, non-actual infinite modes. Whatis the manner of Sophia’s dependence on substance?Spinoza’s discussion of infinite modes suggests that Sophiamust, by definition, follow from God’s absolute nature (eitherimmediately or mediately). If so, then Sophia follows from theabsolute nature of God in \(w^*\), on the assumption that truedefinitions express necessary truths. But in that case, the modaltransfer principle will apply to Sophia in \(w^*\), in which caseSophia’s existence is necessary. However, again assuming thatnecessity entails actuality, Sophia would be actual, pace our initialassumption. QED.

Of course, that reasoning relies on possible world semantics and someloaded (though plausible) theses about relations between possibleworlds. Perhaps Spinoza could reach a similar conclusion withoutrecourse to all that. Spinoza could instead appeal back to hisplentitude principle and its basis in the PSR. If there could havebeen more infinite modes than there in fact are, these non-actual,merely possible modes must be compossible with the collection ofnecessarily existing infinite modes. (Another plausible assumption,expressed loosely: if something is not compossible with whatnecessarily exists, then its existence is not possible.) But if therewere non-actual infinite modes that were compossible with thecollection of necessarily existing infinite modes, what could explaintheir non-existence? Unless an answer can be given, Spinoza will inferfalsity from a violation of the PSR. We again reach the conclusion ofnecessitarianism with respect to every infinite mode. Like substance,every possible infinite mode necessarily exists.^[9]

1.2.3 Finite modes: A first pass

Infinite modes exist necessarily because they follow necessarily fromsomething that exists necessarily, namely God. What about finitethings like furniture and people? This much seems clear:if afinite mode follows from an infinite mode or from substance itself,then by the modal transfer principle, it exists necessarily too. Butdoes any finite mode follow from an infinite mode or from substance?This is where the aforementioned “gap” between infiniteand finite modes becomes modally significant. Consider what Spinozasays in the lengthy and important demonstration of Ip28:

Whatever has been determined to exist and produce an effect has beenso determined by God (by Ip26 and Ip24c). But what is finite and has adeterminate existence could not have been produced by the absolutenature of an attribute of God; for whatever follows from the absolutenature of an attribute of God is eternal and infinite (Ip21). It had,therefore, to follow either from God or from an attribute of Godinsofar as it is considered to be affected by some mode….But italso could not follow from God, or from an attribute of God, insofaras it is affected by a mode which is eternal and infinite (by Ip22).It had, therefore, to follow from or be determined to exist andproduce an effect by God insofar as it is modified by a mode which isfinite and has a determinate existence…and in turn, this causeor mode…had also to be determined by another which is alsofinite and has a determinate existence; and again…and so always(by the same reasoning) to infinity.

On a cursory reading of this passage, Spinoza seems to say that nofinite mode follows from either an infinite mode or from “theabsolute nature of an attribute of God,” lest that mode be“eternal and infinite,” pace the nature of finite modes.If so, then perhaps Spinoza’s point in this passage is thatparticular finite modes, like the desk, follow fromonlyother particular finite modes, such as a pile of wood, whichthemselves follow from only other finite modes, such as some trees,and so on.^[10] If so, then it appears that finite modes do not follow from anythingthat exists necessarily, in which case the modal transfer principlewill not apply. Absent some other source of necessity for finitemodes, it follows that Spinoza is not a necessitarian.

Suppose, however, that the causal history of the desk is traced allthe way back to the very beginning of the world. Surely the startingpoint of the universe — that from which all the subsequentobjects and events necessarily follow — surely the initial modefollows from God’s nature or from one of God’s infinitemodes. If so, then by the modal transfer principle, the first finitemode will exist necessarily, and so everything that follows from it,including the desk, will exist necessarily too.

Spinoza rejects this reasoning. He has little sympathy with thetraditional monotheistic idea that God created the worldexnihilo, and he denies that there is a true “in thebeginning” style cosmogony. In the quotation from Ip28 above,Spinoza denies that the series of finite modes has an initial startingpoint. Spinoza thinks that the series of finite objects extendsbackwards in time in an infinitely long causal chain that contains noinitial state. For every finite cause of the desk, there will alwaysbe a temporally prior finite cause of that cause. And a prior causeof the cause of that cause. And so on,ad infinitum. Primafacie, there is no PSR violation with this picture. For everyparticular finite object, there is a sufficient reason for itsexistence and characteristics in terms of its prior finitecauses. Each finite object follows from and is thus explained by theprior state of the world, whose constituents are also explained by aprior state. If that is all Spinoza intended to say about the modalstatus of finite things, then one could read his fiery denials ofcontingency as defenses of mere causal determinism and not full-blownnecessitarianism.

1.2.4 The problem of the gap

An important lesson from the previous section is that if there is acausal gap between finite modes and infinite modes, thenSpinoza’s modal transfer principle will not apply to finitemodes, since condition (ii) will remain unsatisfied in each case.Finite things will be causally determined solely by other finitethings, none of which exist necessarily.

However tempting, this picture has trouble making sense ofSpinoza’s repeated claims that everything is causedbyGod (Ip25–26), a claim Spinoza repeats in the very firstsentence of Ip28d itself. Spinoza frequently emphasizes thatGod’s power or essence is the cause and explanation ofeverything that exists (Ip16, 17, 29s, 33, IAppendix). But if finitemodes follow only from other finite modes, then it seems that they donot follow from God or substance, which violates one of themost basic features of modes, namely their dependence, qua modes, onsubstance (Id5).

This is a notoriously difficult question facing Spinoza’smetaphysics, one that was raised by Leibniz just a year afterSpinoza’s death (Leibniz 1969, 203). Sometimes this worry washistorically expressed as whether Spinoza can “derive” thefinite from the infinite, but it is not really a question of logicaldeduction (Hübner 2014). The issue is whether Spinoza canconsistently maintain that God is the cause of all things and thatfinite things follow only from other finite things.

One possible response would appeal to the close relationship betweenfinite modes and the power of God. Spinoza sometimes describes finitemodes as limited expressions of God’s own power (Ip36d; IVp4d),in which case perhaps being caused by other finite modes is a wayof being determined by God’s power. The success of this responsedepends on the relationship between God and God’s modes forSpinoza, an interpretive point that is also heavily disputed. Thisreply would not work, for instance, if the fundamental connectionbetween substance and modes is purely causal.

Curley has proposed a more elaborate and elegant solution forreconciling Ip28 and the claim that all modes follow from substancewithout positing any closer relationship between God and finite modes.(This is understandable since Curley is the leading advocate of the“causal only” interpretation of how modes depend onsubstance.) Curley suggests that Spinoza’s finite modes are onlypartially determined by other finite modes (Curley 1969).They are also partially determined by infinite modes, which Curleyunderstands to be general features of the world described by the lawsof nature. The desk follows partly from infinite modes and partly fromother particular finite modes.

In more contemporary terms, Curley’s proposal is that everystate of the world is determined by the laws of nature plus the priorstate of the world. The laws of nature and the antecedent state eachcontribute to bringing about the desk, but neither is sufficient onits own. This division of labor would allow Spinoza to overcome theproblem of the gap without violating Ip28. Particular finite modes dofollow partly from God’s nature, in virtue of following partlyfrom infinite modes – but only partly. They also follow partlyfrom other finite modes. Admittedly, Spinoza does not say in Ip28 thatfinite modes follow onlypartially from other finite modes,but neither does he explicitly say that finite modes followentirely from other finite modes.

If Curley is correct, then because finite modes are onlypartially determined by infinite modes, the modal transferprinciple will not apply to finite modes. (One assumption here is thatcondition (i) requires following fromentirely.) This blocksnecessitarianism, since no finite mode would follow entirely fromsomething that exists necessarily. Thus, Curley’s interpretationconcludes, particular finite modes do not exist necessarily, despite(partly) following from God’s nature. Hence full-blownnecessitarianism with respect to finite modes is false and AP1, AP2,and AP3 represent genuine alternative possibilities for Spinoza. Thisfinds support in passages like IIa1:

The essence of man does not involve necessary existence, that is, fromthe order of Nature it can happen equally that this or that man doesexist or that he does not exist.

Although the first half of that statement is thoroughly traditional,Spinoza’s claim that the order of Nature leaves the existence ornon-existence of particular finite things undetermined seems to positgenuine contingency in the world. (In IIp10d, Spinoza cites IIa1 andclaims that it would be “absurd” to conclude that aparticular person exists necessarily, though it is unclear whether theabsurdity lies in the modal conclusion itself or in the reasoningabout finite essences that would lead to the modal conclusion.)

As for those passages in which Spinoza seems to profess full-blownnecessitarianism (i.e., Ip16, 17, 29, 33, IAppendix), his appeals tonecessity could be ambiguous between a strong form of determinism andfull-blown necessitarianism. Yes, everything finite necessarilyfollows from something else and so everything finite is“necessary” in the sense of “being fullydetermined,” but nothing finite follows entirely from somethingthat necessarily exists, and so no finite mode exists necessarily inthe full-blown sense of that term.^[11] Importantly, Curley defends Spinoza’s rejection ofnecessitarianism without positing a complete causal gap between finitemodes and God’s nature; finite modes do partly follow from Godand God’s infinite modes.

However, consider AP1 again, the possibility of an entirely differentcollection of finite modes. According to Curley, because no member ofthe collection exists necessarily, the collection itself is notnecessary. That is, God could have brought about an entirely differentseries of finite modes. If so, what explains whythis seriesof finite modes exists as opposed to one of the alternative possibleseries? (The question is not why Godchose to create thisseries of modes rather than another possible series, a question thatanimated Leibniz. Spinoza denies that God has a will in thetraditional sense, and so talk aboutchoosing one possibleworld over another has no place in Spinoza’s system (Ip17s andIIp49c). Nonetheless, the PSR demands a reason in virtue of which Godrealizes this series of finite modes rather than another possibleseries.)

I noted earlier that Spinoza could explain why a particular finitemode exists by appealing (in part) to other particular finite modes,namely its actual causes. But Spinoza could not explain why thisseries, as opposed to some other series, exists by appealing to otherparticular existing modes. This would be akin to explaining why anentire series of causes exists by appealing to one of those verycauses. We aren’t asking why any particular mode exists, but whythis whole series, and not some other series, exists. Appealing to yetanother contingent fact appears to get us nowhere towards accountingfor the entire set of contingent facts.^[12]

Nor could Spinoza appeal to substance or infinite modes to explain theentire series of finite modes, for two reasons. First, according toCurley’s own account, substance and its infinite modes do notfully explain or cause any particular finite mode (by Ip28). But asthere seems to be nothing to the collection of finite modes beyond theindividual members themselves, it is unclear how substance and itsinfinite modes could fully explain or cause the entire series withoutfully causing or explaining any individual member.

Second, if the entire series of finite modes were caused by God orsomething that necessarily followed from God, then the entire serieswould exist necessarily after all (pace AP1). Remember that causation,necessary connection, and following-from track each other, accordingto Spinoza. So if the entire series of finite modes follows fromsomething that exists necessarily, then by the modal transferprinciple, the series itself would also exist necessarily. If so, thenthere would not be any alternative possible series to the seriesof actual finite modes. Furthermore, it is hard to see how Spinozacould block the transfer of necessity from the series of finite modesto the individual members of that series, in which case both AP2 andAP3 would be ruled out as well.

This leaves us with an interpretive dilemma. On the one hand,Curley’s account respects both the demonstration of Ip28 andSpinoza’s frequent claims that all modes follow from God’snature. A consequence of his account is that Spinoza is not afull-blown necessitarian. On the other hand, Curley’s Spinozamust reject very natural-sounding demands of the PSR. Spinoza wouldhave to accept that there is no explanation why this entire series offinite modes exists rather than another possible series, a pointCurley has conceded (Curley and Walski, 1999).

That concession might seem like too high an interpretive price to pay,especially since there is no independent reason to think Spinozarejects the demands of the PSR when applied to the entire series offinite modes. It would be nice if Spinoza could accept an unrestrictedversion of the PSR and still preserve the claim in Ip28d thatparticular finite modes do not follow from infinite modes or theabsolute nature of God without recreating the problematic gap. In thenext section, we’ll consider an attempt to do just that. Aconsequence of this alternative reading will be that Spinoza endorsesfull-blown necessitarianism.

1.2.5 Finite modes: a second pass

Let us return to Spinoza’s crucial claim about finite modes inIp28. He states that particular finite modes (a) do not follow from“the absolute nature of an attribute of God,” even though(b) they follow from an attribute of God “insofar as it isconsidered to be affected by some mode.” (As a reminder: we willcontinue to drop the reference to attributes for ease of expression.)Two questions immediately arise:

(1)

What is the difference between following from theabsolute nature of God and merely following from God in thesecond, more qualified manner?

(2)

Why should the way a particular thing isconsidered berelevant for this distinction?

According to one prominent interpretation (Garrett 1991 and 2018), tofollow from theabsolute nature of God is to follow in anunqualified, pervasive and permanent manner, as infinite modes do(Ip21–23). Spinoza denies that finite modes follow in that way.However, following from God’s nature in a more qualified waydoes not imply that finite modes do not follow from God at all –to infer that would be to reintroduce the problem of the gap. Rather,Garrett contends, Spinoza denies only that any particular finite modefollows from God’s absolute natureindependently of itsrelations to other finite objects. This leaves open thepossibility that although no particular finite mode follows from theabsolute nature of God, the entire collection of finite modes as awhole follows from the absolute nature of God or from an infinite modeof God.

Garrett’s account presents a five-fold division ofSpinoza’s expression “following from God’snature”:

1. The immediate infinite modes follow directly from God’sabsolute nature.
2. The mediate infinite modes follow indirectly from God’sabsolute nature.
3. The infinite collection of finite modes, considered as a whole,follows indirectly from God’s absolute nature.^[13]
4. Each particular finite mode, considered in relation to the othermembers of the series, follows from God’s non-absolutenature.
5. Each finite mode, considered independently of its relation to theother members of the series, does not follow from God’snature.

If we apply Spinoza’s modal transfer principle to this division,the objects described in [i] and [ii] exist necessarily. Similarly,the necessity of God’s nature in [iii] trickles down thefollowing-from relation, and so even though the series as a wholefollows only indirectly from God, its existence would nonetheless benecessary, as with mediate infinite modes.

What about particular finite modes described in [iv]? OnGarrett’s proposal, their existence too will be necessary, whichcommits Spinoza to full-blown necessitarianism. To see why, noticethat the difference between [iii] and [iv] is not a function of thepresence or absence of the following-from relation itself. Thedifference is between following from God’s absolute vs.non-absolute nature, whatever that distinction amountsto. Spinoza’s modal transfer principle is indifferent tothe difference between [iii] and [iv]. The principle is toocoarse-grained to track the absolute/non-absolute distinction; ittracks only the following-from relation from a necessarily existingsource. Since both conditions of the principle are satisfied in [iv],necessity is transferred from the entire collection of finite modes tothe individual members themselves. Thus, the desk exists necessarily.If this is correct, Spinoza can consistently claim that every finitemode exists necessarily and follows from God’s natureinsome way, while still maintaining that no particular modesfollows directly or indirectly from theabsolute nature ofGod.

The objects described in [v] do not follow from God’s nature atall, in which case the modal transfer principle will not be satisfied.Insofar as that is the only available source for their necessity, itfollows that they do not exist necessarily. But what is the differencebetween the objects described in [iv] and the objects described in[v]? In one sense, nothing: they are the same finite modes! Thatcannot be the full story, however, lest there be no explanation whythe modes in [iv] follow from the nature of God whereasthose verysame modes in [v] do not. The only difference between [iv] and[v] is how a mode isconsidered in each case. (AlthoughGarrett himself uses this “considered” claim, he does notsay whether he thinks there are any true ways of considering objectscorresponding to [v].)

Hence, if the desk is considered in relation to the entire series offinite modes, it follows from God’s nature and existsnecessarily. Considered independently of that relation — if suchcan be done — the desk does not follow from God’s natureand does not exist necessarily. This gives rise to a more preciseversion of our earlier question:

(2′)

Why should the way a particular thing isconsidered in relation to other particular things be relevantfor whether it follows from God?

And, since that difference also generates a modal difference, weshould also ask:

(3)

Why should the way a thing is considered be relevant for itsmodal status?

Answering these questions in the next section will drive us yet deeperinto Spinoza’s modal metaphysics. First, however,Garrett’s account faces an independent worry (Curley and Walski1999, Huenemann 1999). Return to the relationship between [iii] and[iv]. There is supposed to be a significant difference between themanner in which the collection of finite modes follows from Godasa whole and the manner by which any particular member of thatcollection follows from God. However, if the entire collection offinite modes follows indirectly from God’s absolute nature, thatseems to imply that each individual member of the seriesalso follows from God’s absolute nature. Imagine trying tocover the collection of objects on my desk in coffee without making itthe case that each object on my desk is covered in coffee. This seemsimpossible, as there is nothing more to the collection of things on mydesk being covered in coffee than each and every thing on my deskbeing covered in coffee. Even worse, it is hard to see how the entireseries of finite modes could have the propertyfollowing fromGod’s absolute nature if no member of the series has thatproperty.

The most promising line of response denies that the series of finitemodes is nothing above and beyond its individual members. Followingothers, the entirety of finite modes has been described as a“series” or “collection,” a label thatnaturally suggests that the properties of the entire collection willbe posterior to and derivative from the properties of its individualmembers. Spinoza himself rarely refers to just the collection offinite modes with a single expression, though he sometimes includesthem in his locution “the order of nature” and hedescribes them as a “series” twice, both outside theEthics (C I/41 and C I/307). Regardless of the terminology,one could contend that the whole series is more than just the sum ofits the members. Spinoza does sometimes suggest that wholes can beprior to their parts (Ep32, IIp13le7s), though other times he suggeststhat parts are always prior to wholes (Ip15). Whether the series offinite modes is more holist or atomistic, and whether, on a holistmereological account, one of the non-supervening properties of thewhole series isfollowing from God’s absolute nature,are still open interpretive questions. The soundness of this replywill likely turn on whether or not the collection of finite modes isitself an infinite mode, a point about which interpreters continue todisagree.

2. The Nature of Modality

We have now seen two competing accounts of Spinoza’s views aboutthe modal status of finite objects. Some argue that Spinoza endorses astrong form of determinism that falls short of full-blownnecessitarianism. On this reading, finite modes do not existnecessarily and there are alternative possibilities to the series ofactual finite modes that God did not bring about. Others have arguedthat Spinoza’s account of the relationship between God andfinite modes readily accommodates full-blown necessitarianism andthat, given the large number of passages in which Spinoza appears toaffirm necessitarianism without qualification, there issufficient evidence that Spinoza intentionally endorsedfull-blown necessitarianism.

Like almost all discussions of Spinoza’s modal commitments, thisdispute focus on thedistribution of modal properties: whichthings exist necessarily? Far less attention has been given toSpinoza’s account of thenature of modality. Thissection discusses whether Spinoza has an account of modality itself,and if so, what light that account sheds on the dispute over hisalleged necessitarianism.

Spinoza is emphatic that particular modal ascriptions have reasonsbehind them: “A thing is called necessary either by reason ofits essence or by reason of its cause” (Ip33s1). But wecan also consider a higher-order question: for whatreason(s) do modal ascriptions work in the way that Spinoza claimsthey do? For ease, let us focus on modalproperties insteadof modal ascriptions. The question is similar to the one raisedearlier about causation. What explains causation itself? Arguably,Spinoza’s answer is that causal relations obtain in virtue ofconceptual connections between causal relata. A parallel question canbe raised about modality itself. Do basic modal properties obtain invirtue of other, non-modal properties or is modality primitive forSpinoza?

Given Spinoza’s embrace of the PSR and his efforts to explainother dependence relations (such as causation and, perhaps,inherence), it would be surprising and disappointing if modality got afree explanatory pass. Of course, we probably should not expectSpinoza to have anything like a full-blown theory of modality in theforms that contemporary metaphysicians now provide (for an example,see the entry on thepossibilism-actualism debate). Only in recent decades have philosophers come to appreciate howcomplex and rich the metaphysics of modality is, and Spinoza would bein good company if he says things that seem, by today’sstandards, mostly underdeveloped. Nonetheless, he may have thebeginnings of an account that helps illuminate his other modalcommitments.

A promising place to start is the modal status of God’sexistence. In Ip11, Spinoza claims that God necessarily exists. Butwhat is it in virtue of which God necessarily exists? This might soundlike an odd question. Once explanations reach a necessarily existingobject, are there furtherin virtue of questions to be askedabout that object’s existence? More generally, when we reachnecessity, haven’t we reached the end of explanations?^[14] Not always: mathematics is full of asymmetricalexplanatory relations among necessarily true propositions.Similarly, Spinoza thinks that substance causes and asymmetricallyexplains necessarily existing infinite modes. Hence Spinoza mustbelieve that dependence and explanation are more fine-grainedrelations than modern logical entailment, since according to thelatter, every necessary proposition entails and is entailed by everyother necessary proposition.

Spinoza explains the necessity of God’s existence by appealingto God’s nature. This may sound like a non-answer, but it isnot. Spinoza is not claiming that there are no explanatory grounds forGod’s existence; he is claiming that facts about God’snature explain the modality of God’s existence. What aboutGod’s nature explains God’s existence? In Ip7 and Ip11,Spinoza appeals to an involvement relation between the concept ofGod’s essence and the concept of God’s existence. That is,God exists in virtue of the fact that the concept of God involves theconcept of existence. Spinoza also thinks that the conceptualinvolvement relation between God and existence explains the fact thatGodnecessarily exists. In Ip19d, Spinoza writes,

For God (by Id6) is substance, which (by Ip11) necessarily exists,that is (by p7), to whose nature it pertains to exist, or (what is thesame) from whose definition it follows that he exists.

In Ip7, Spinoza equates “pertaining to its nature toexist” with “essence necessarily involvingexistence” and “causing itself.” Self-causation inturn is explained in Id1 as a “nature that cannot be conceivedexcept as existing.” That is, what explains the necessity ofGod’s existence is the fact that the very concept of Godinvolves the concept of existence. He repeats these connections inIp24d, “For that whose nature involves existence (considered initself) is its own cause, and exists only from the necessity of itsnature.” In other words, Spinoza explains necessity in terms ofconceptual connections. Although Spinoza does not develop a richeraccount of conceptual relations that Leibniz will later achieve, hisgeneral idea seems to be that conceptual relations are the relationsthat explain and ground necessary connections.

Spinoza makes similar appeals to conceptual relations when he invokesgeometrical examples to describe the necessity with which other thingsfollow from God:

…all things have necessarily flowed, or always follow, by thesame necessity and in the same way as from the nature of a triangle itfollows…that its three angles are equal to two right angles(Ip17s).

Spinoza later identifies this same geometrical relationship with theconceptual involvement relation (IIp49). What it is for things tofollow from God necessarily is for those things to be (asymmetrically)conceived through God, whose concept involves (the concept of)existence. The necessity of God and the necessity of existing thingsare both explained by and grounded in conceptual relations. Spinozamakes this connection emphatic in Ip35, “Whatever we conceive tobe in God’s power, necessarily exists.”

Conversely, contingency obtains in virtue of the lack of certainconceptual connections. In the case of contingent existence, an objectexists contingently just in case its concept is neither connected tothe concept of existence nor to something else whose concept isconnected to the concept of existence. Hence if a mode isconceived in such a way that it is not conceived in relation tosomething involving existence, it will exist contingently and notnecessarily (as per Ia7). The point is not just that it would beconceived as contingent. On this account, how a thing isconceived partly fixes its modal status. In explaining modal featuresin terms of an involvement relation between concepts, Spinoza providesan answer to (3) from the previous section and thereby identifieshimself with a long and distinguished tradition of philosophers whoexplain modal facts by appeal to conceptual relations.

This account also explains why Spinoza is attracted to his modaltransfer principle in the first place. Recall that the modal transferprinciple states that necessity transfers along following-from chainswhose nodes include at least one necessarily existing thing. We sawearlier that Spinoza’s following-from relation is a causalrelation and that causal relations are conceptual relations forSpinoza. But we just saw that necessity is also partly a function ofconceptual relations. Thus necessity transfers along following-fromchains because both necessity and following-from are grounded in thesame relations of conceptual involvement. The underlying conceptualnature of modality, causation, and following-from explains whySpinoza’s modal transfer principle works.

Another upshot of all this is that modality is not wholly extensionalfor Spinoza. The ways in which objects are conceived partly determinesa thing’s modal status. In particular, whether a finite modeexists necessarily or not depends in part on whether it is conceivedthrough something whose concept involves existence. (For furtherdiscussion, see Newlands 2010b and Newlands 2017.)

2.1 Necessitarianism Vindicated

With this analysis in hand, let us return to Garrett’s proposedaccount of Spinoza’s necessitarianism. Garrett claims in [iv]that each particular mode, conceived in relation to all the otherparticular modes, follows from God’s nature, and he concludesthat therefore every finite mode exists necessarily. However,according to [v], the same finite mode conceived independently of therelation to every other finite modes fails to follow from God and sofails to exist necessarily. Spinoza’s conceptual account ofmodality explains why he thought modality works in this particularway.

Suppose the entire collection of finite modes, considered as a whole,follows from a necessarily existing infinite mode. Hence, the entirecollection as a whole exists necessarily. In order for a particularfinite mode in that collection to exist necessarily, it must beconceived as following from something that exists necessarily. How cana finite mode be conceived as following from something that existsnecessarily? The answer is clear: by being conceived in relation tothe whole collection. That is, when finite modes are considered inrelation to all the other finite modes, the right conceptualconnection obtains and Spinoza’s modal transfer principle issatisfied. This provides an answer to (2′) from the previoussection. Whether a mode is considered in relation to the rest of theseries is relevant to its modal status because (a) modal facts aresensitive to the conceptual relations that the considering relationpicks up on and (b) considering a particular finite mode in relationto the whole series of finite modes tracks the relevant conceptualconnection that satisfies the modal transfer principle.

Of course, not just any way of considering a finite mode will berelevant for its modal status. Considered as “the largest pieceof furniture in the office,” the desk does not existnecessarily. By Spinoza’s lights, the way of conceiving the deskneeds to involve something that follows from God’s nature if thedesk is to exist necessarily. This is why, if Garrett is correct,considering the desk in relation to the rest of the entire series offinite objects is relevant for its modal status, whereas consideringthe desk in other, less causally relevant or more isolated ways, is not.^[15]

2.2 Non-necessitarianism also vindicated

If particular finite things exist necessarily in virtue of beingconsidered in relation to the whole series of finite things, twolingering questions remain:

(4) Can you and I ever grasp such all-encompassing ways of conceivingparticular things?

(5) Are there other, less inclusive ways of considering a finiteobject in virtue of which it does not exist necessarily?

With the respect to (4), Spinoza’s answer is unfortunatelynegative. Spinoza sometimes describes the mental corollary of thesevery inclusive and complete ways of conceiving objects in terms ofadequacy, and he is very pessimistic about our ability tohave adequate ideas of particular things (see especiallyIIp24–31, though he holds out more hope in Part Five). Spinozaeven links our natural tendencies to represent objects independent oftheir infinitely extensive causal networks with their contingency(IIp31c), just as the above interpretation predicts. So while we canunderstand the metaphysical principles which guarantee the necessaryexistence of a finite thing insofar as it is conceived in relation toevery other finite thing, we tend to adopt far more limited conceptsof finite things, in virtue of which necessitarianism is false.Spinoza remains confident thatthere is a complete way ofconceiving a particular finite object in relation to all others, butit is unlikely that we will ever be able to psychologically grasp suchcomplete and necessitating concepts. Spinoza’smetaphysics meets his psychology here, and psychology wins.

This is anunfortunately negative answer in the light ofSpinoza’s ethical theory. As a systematic thinker, Spinozathinks metaphysical conclusions about modality have consequences forethics. Although pursuing the relations between Spinoza’smetaphysics and ethics are beyond the scope of this entry (seeNewlands 2018), Spinoza clearly thinks that ethically relevantconclusions follow from his metaphysics of modality. For example, hewrites in Vp6:

Insofar as the mind understands all things as necessary, it has agreater power over the affects, or is less acted on them.

Spinoza thinks we morally improve by gaining power over our passiveaffects and becoming more active (Vp4), so our inability to conceivefinite things as related to everything else (and so as existingnecessarily) means our prospects for moral perfection are quitedim.

With respect to (5), Spinoza suggests that there are more and lesscomplete ways of genuinely conceiving objects (see, for instance,Ip24d and IVd3–4). If there are true but incomplete ways ofconceiving objects, Spinoza will occupy the interesting position ofconsistently affirming both necessitarianism and its denial, relativeto these different ways of conceiving objects. This pairing soundslike a contradiction until we appreciate the force of Spinoza’sconceptualist account of modality. If the truth-value of modalpredications is sensitive to ways of conceiving objects (as a modernday anti-essentialist might agree), and if Spinoza endorses a varietyof modally salient ways of conceiving objects, then he canconsistently affirm both the truth and falsity of full-blownnecessitarianism relative to different ways of conceiving finiteobjects.

If this is all correct (a very big “if”!), then Garrettand Curley’s conclusions can both be right, thoughneither tells the complete modal story. Something less than full-blownnecessitarianism will be true in virtue of ways of conceiving objectsthat do not include their relations to the entire, infinitely largeand complex range of other particular things. At the same time,full-blown necessitarianism will also be true in virtue of ways ofconceiving finite things that are maximally inclusive with respect torelations to the rest of the world. This middle ground provides ananswer to Curley’s otherwise worrisome objection to thenecessitarian interpretation: “If each particular feature of theuniverse, considered in itself, is contingent, then their totality isalso contingent” (Curley 1988, 49).^[16] This expansion of contingency from the part to the whole would betrue only if the shift in the ways finite things are conceived did notsometimes entail a shift in their modal status. Although this is avery widespread essentialist assumption today, it is a falseone according to this reading of Spinoza’s modal theory.Just as necessitarianism at the most expansive conceptual level doesnot jeopardize contingency at narrower levels, so too contingency atnarrower levels need not bleed into the modal status of thingsconceived in the most expansive way.

3. The Ground of Modality

A final and underexplored topic in Spinoza’s modal metaphysicsconcerns what we might call theground of modality. There wasa lively dispute in the 17^th century about the relationshipbetween God and modality. Although there was a general consensus thatmodal facts – like so much else – depend on God in someway or other, there was considerable disagreement over exactly how tounderstand that dependence. Monotheistic metaphysicians disagreed overboth (a) on what in God modal truths and modal truth-makers depend and(b) by what manner of dependence modal truths and modal-truth makersdepend on God. The first set of issues concerns the divineground of modality and the second concerns thegroundingrelation that modality bears to its ground (for some recentdiscussions, see Chignell 2012 and Newlands 2013).

Spinoza cannot accept two of the most prominent accounts proposed byhis contemporaries. According to Descartes, (a) modal truths and modaltruth-makers depend on God’s volitions and (b) the form ofdependence is efficient causation. According to Leibniz, (a) modaltruths and modal truth-makers depend on God’s ideas andintellectual activities and (b) the form of dependence is ontologicaland does not involve efficient causation. However, Spinoza denies thatGod’s nature contains a will and intellect in the sense requiredfor these accounts (Ip17s).

Nonetheless, Spinoza thinks that all things depend on God (Ip15),and he points to an alternative account of how possibilities depend onGod. He claims that non-existing modes are grounded in God’sactual attributes. “The ideas of singular things, or of modes,that do not exist must be comprehended God’s infinite idea inthe same way as the formal essences of singular things, or modes, arecontained in God’s attributes” (IIp8). He unpacks the“comprehension” or containment of non-divine formalessences in conceptual terms: “Essences [of non-existing things]are comprehended in another in such a way that they can be conceivedthrough it” (Ip8s2). This suggests that the essences of allthings, including non-existing things, are conceptually contained inGod’s attributes.

In more general terms, Spinoza’s idea seems to be thatpossibilities are grounded in God by being actually exemplified byGod, a view that fits nicely with interpretations of Spinoza’smodes as things that inhere in God (see section 1.3 above). Thus, itis possible for something to be thinking because God is actually athinking thing (IIp1d). The grounding of possibility in actuality is avery attractive metaphysical thesis in its own right, andSpinoza’s God has a sufficiently rich nature to ground allpossibilities by actually exemplifying them all (Ip15 and Ip16).

Spinoza’s account of the grounds of modality also presents aninteresting challenge to anyone attracted to the thesis that Godgrounds possibilities, but who wants to deny that God directlyexemplifies every possibility (Newlands 2016). Those unhappy withSpinoza’s expansive divine nature would need to explain how itis that God grounds some possibilities, such as being extended,without actually being extended. One could follow Descartes inharkening back to the Scholastic notion of “eminent”containment, but Spinoza reads that appeal as the name of the problem,not its solution. Leibniz was sometimes attracted to the idea thatevery basic creaturely possibility is formed from God’snon-mental perfections, but he will have a hard time explaininghow every creaturely possibility can be constructed out of the sparseset of traditional divine perfections.

Without reducing creaturely possibilities to God’s actualperfections (as idealists do with extension), Spinoza presents analternative grounding thesis and a challenge. Let every possibility begrounded in God via actual exemplification, even if this requiresexpanding the divine nature beyond its traditional boundaries. Forthose unwilling to follow Spinoza on this expansion, Spinoza’schallenge is for proponents of nearby alternatives to provide anon-metaphorical explanation of how God grounds certain basicpossibilities without actually and directly exemplifying them. Untilsuch an account is given, Spinoza’s biting conclusion offers anunmet challenge: “But by what divine power could [extension orany property not exemplified by God] be created? They are completelyignorant of that. And this shows that they do not understand what theythemselves say” (Ip15s). At the very least, Spinoza’schallenge highlights how his modal metaphysics extends beyond thetopic of necessitarianism and continues to invite widerinvestigation.

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[All references to Spinoza’sEthics use the form ofPartTypeNumberSubtype (so “EIp4d” means Part One,Proposition Four, Demonstration). Other variants of types include“d” for definition, “a” for axiom, and“le” for lemma. Other subtypes include “s” forscholium and “c” for corollary. Spinoza’s lettersare cited as Ep, using their standard numbering. All other citationsfrom Spinoza’s corpus are cited by volume/page of EdwinCurley’sCollected Works, from which all translationsare also taken.

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