Compatibilism is the belief thatfree will anddeterminism are mutually compatible and that it is possible to believe in both without being logically inconsistent.[1] AsSteven Weinberg puts it: "I would say that free will is nothing but our conscious experience of deciding what to do, which I know I am experiencing as I write this review, and this experience is not invalidated by the reflection that physical laws made it inevitable that I would want to make these decisions."[2] The opposing belief, that the thesis of determinism is logically incompatible with the classical thesis of free will, is known as "incompatibilism".
Compatibilists believe that freedom can be present or absent in situations for reasons that have nothing to do withmetaphysics.[3] In other words, that causal determinism does not exclude the truth of possible future outcomes.[4] Because free will is seen as a necessary prerequisite formoral responsibility, compatibilism is often used to support compatibility between moral responsibility and determinism.
Similarly,political liberty is a non-metaphysical concept.[5] Statements of political liberty, such as theUnited States Bill of Rights, assume moral liberty: theability to choose to do otherwise than what one does.[6]
Compatibilism was mentioned and championed by the ancientStoics[7] and some medievalscholastics. More specifically, scholastics likeThomas Aquinas and laterThomists (such asDomingo Báñez) are often interpreted as holding that human action can be free, even though an agent in some strong sense could not do otherwise than what they did. Whereas Aquinas is often interpreted to maintain rational compatibilism (i.e., an action can be determined by rational cognition and yet free), later Thomists, such as Báñez, develop a sophisticated theory of theological determinism, according to which actions of free agents, despite being free, are, on a higher level, determined by infallible divine decrees manifested in the form of "physical premotion" (praemotio physica), a deterministic intervention of God into the will of a free agent required to reduce the will from potency to act. A strong incompatibilist view of freedom was, on the other hand, developed in theFranciscan tradition, especially byDuns Scotus, and later upheld and further developed byJesuits, especiallyLuis de Molina andFrancisco Suárez. In the early modern era, compatibilism was maintained byEnlightenment philosophers (such asDavid Hume andThomas Hobbes).[8]
During the 20th century, compatibilists presented novel arguments that differed from the classical arguments of Hume, Hobbes, andJohn Stuart Mill.[9] Importantly,Harry Frankfurt popularized what are now known asFrankfurt counterexamples to argue against incompatibilism,[10] and developed a positive account of compatibilist free will based onhigher-order volitions.[11] Other "new compatibilists" include Gary Watson,Susan R. Wolf,P. F. Strawson, andR. Jay Wallace.[12] Contemporary compatibilists range from the philosopher and cognitive scientistDaniel Dennett, particularly in his worksElbow Room (1984) andFreedom Evolves (2003), to the existentialist philosopherFrithjof Bergmann.[13] Perhaps the most renowned contemporary defender of compatibilism isJohn Martin Fischer.
A 2020 survey found that 59% of English-publishing philosophers accept or lean towards compatibilism.[14]
Compatibilists often define an instance of "free will" as one in which the agent had the freedom to act according to their ownmotivation. That is, the agent was not coerced or restrained.Arthur Schopenhauer famously said: "Man can do what he wills but he cannot will what he wills."[15] In other words, although an agent may often be free to act according to amotive, the nature of that motive is determined. This definition of free will does not rely on the truth or falsity ofcausal determinism.[3] This view also makesfree will close toautonomy, the ability to live according to one's own rules, as opposed to being submitted to external domination.
Some compatibilists hold both causal determinism (all effects have causes) andlogical determinism (the future is already determined) to be true. Thus statements about the future (e.g., "it will rain tomorrow") are either true or false when spoken today. This compatibilist free will should not be understood as the ability to choose differently in an identical situation. A compatibilist may believe that a person can decide between several choices, but the choice is always determined by external factors.[16] If the compatibilist says "I may visit tomorrow, or I may not", he is saying that he does not know what he will choose—whether he will choose to follow the subconscious urge to go or not.
Alternatives to strictlynaturalist physics, such asmind–body dualism positing a mind or soul existing apart from one's body while perceiving, thinking, choosing freely, and as a result acting independently on the body, include both traditional religious metaphysics and less common newer compatibilist concepts.[17] Also consistent with both autonomy andDarwinism,[18] they allow for free personal agency based on practical reasons within the laws of physics.[19] While less popular among 21st-century philosophers, non-naturalist compatibilism is present in most if not almost all religions.[20]
A prominent criticism of compatibilism isPeter van Inwagen'sconsequence argument.
Critics of compatibilism often focus on the definitions of free will: incompatibilists may agree that the compatibilists are showingsomething to be compatible with determinism, but they think that thissomething ought not to be called "free will". Incompatibilists might accept the "freedom to act" as anecessary criterion for free will, but doubt that it issufficient. The incompatibilists believe that free will refers togenuine (i.e., absolute, ultimate, physical) alternate possibilities for beliefs, desires, or actions,[21] rather than merelycounterfactual ones.
The direct predecessor to compatibilism wassoft determinism (a term coined by William James, which he used pejoratively).[22] Soft determinism is the view that we (ordinary humans) have free will and determinism is true. (Compatibilists, by contrast, take no stand on the truth-value of determinism.) James accused the soft determinists of creating a "quagmire of evasion" by stealing the name of freedom to mask their underlying determinism.[22]Immanuel Kant called it a "wretched subterfuge" and "word jugglery".[23] Kant's argument turns on the view that, while all empirical phenomena must result from determining causes, human thought introduces something seemingly not found elsewhere in nature—the ability to conceive of the world in terms of how itought to be, or how it might otherwise be. For Kant, subjective reasoning is necessarily distinct from how the world is empirically. Because of its capacity to distinguishis fromought, reasoning can "spontaneously" originate new events without being itself determined by what already exists.[24] It is on this basis that Kant argues against a version of compatibilism in which, for instance, the actions of the criminal are comprehended as a blend of determining forces and free choice, which Kant regards as misusing the wordfree. Kant proposes that taking the compatibilist view involves denying the distinctly subjective capacity to re-think an intended course of action in terms of whatought to happen.[23]
Free will is the capacity of conscious agents to choose a future course of action among several available physical alternatives.