Philosophy 350 Prof. Clare Batty Free Will: Van Inwagen, “The Incompatibility of Free Will and Determinism” Van Inwagen argues for incompatibilism: the view that free will and determinism are incompatible He does not argue that determinism is true or false. 1. Defining Determinism Two conditions of a notion of ‘state of the world’: i. ii.
Our concept of state must be such that, given that the world is in a certain state at a certain time, nothing follows logically about its states at other times; If there is some observable change in the way things are (e.g. if a white cloth becomes blue), this change must entail some change in the state of the world.
Determinism is the conjunction of two theses: a. b.
For every instant of time, there is a proposition that expresses the state of the world at that instant; If A and B are any propositions that express the state of the world at some instants, then the conjunction of A with the laws of physics entails B.
(proposition: roughly, a non-linguistic bearer of truth-value) 2. An Agent’s Abilities Van Inwagen introduces a way of speaking that can help us in talking about an ability or inability to act otherwise. He suggests that we use sentences of the form: S can render [could have rendered]…false, where ‘…’ is replaced by the name of a proposition. According to Van Inwagen, this way of speaking is very useful in discussing the relation between free will (a thesis about abilities) and determinism (a thesis about propositions). 3. The Consequence Argument General form: After due deliberation, a subject refrains from performing a certain contemplated act. If determinism is true, the subject could not have performed that act. Van Inwagen’s Judge Case: Suppose T is the instant at which our judge, J, did not raise his hand. Suppose T0 is some instant of time earlier than J’s birth. Let ‘P0’ denote the proposition that expresses the state of the world at T0. Let ‘P’ denote the proposition that expresses the state of the world at T. Let ‘L’ denote the conjunction into a single proposition of all laws of physics. THE CONSEQUENCE ARGUMENT: (1) If determinism is true, then the conjunction of P0 and L entails P. (2) If J had raised his hand at T, then P would be false. (3) If (2) is true, then if J could have raised his hand at T, J could have rendered P false. (4) If J could have rendered P false, and if the conjunction of P0 and L entails P, then J could have rendered the conjunction of P0 and L false. (5) If J could have rendered the conjunction of P0 and L false, then J could have rendered L false. 1
(6) J could have rendered L false. (∴) If determinism is true, J could not have raised his hand at T.
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Our concept of state must be such that, given that the world is in a certain state at a certain time, nothing follows logically about its states at other times; If there is some observable change in the way things are (e.g. if a white cloth becomes blue), this change must entail some change in the state of the world.
Determinism is the conjunction of two theses: a. b.
For every instant of time, there is a proposition that expresses the state of the world at that instant; If A and B are any propositions that express the state of the world at some instants, then the conjunction of A with the laws of physics entails B.
(proposition: roughly, a non-linguistic bearer of truth-value) 2. An Agent’s Abilities Van Inwagen introduces a way of speaking that can help us in talking about an ability or inability to act otherwise. He suggests that we use sentences of the form: S can render [could have rendered]…false, where ‘…’ is replaced by the name of a proposition. According to Van Inwagen, this way of speaking is very useful in discussing the relation between free will (a thesis about abilities) and determinism (a thesis about propositions). 3. The Consequence Argument General form: After due deliberation, a subject refrains from performing a certain contemplated act. If determinism is true, the subject could not have performed that act. Van Inwagen’s Judge Case: Suppose T is the instant at which our judge, J, did not raise his hand. Suppose T0 is some instant of time earlier than J’s birth. Let ‘P0’ denote the proposition that expresses the state of the world at T0. Let ‘P’ denote the proposition that expresses the state of the world at T. Let ‘L’ denote the conjunction into a single proposition of all laws of physics. THE CONSEQUENCE ARGUMENT: (1) If determinism is true, then the conjunction of P0 and L entails P. (2) If J had raised his hand at T, then P would be false. (3) If (2) is true, then if J could have raised his hand at T, J could have rendered P false. (4) If J could have rendered P false, and if the conjunction of P0 and L entails P, then J could have rendered the conjunction of P0 and L false. (5) If J could have rendered the conjunction of P0 and L false, then J could have rendered L false. 1
(6) J could have rendered L false. (∴) If determinism is true, J could not have raised his hand at T.
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(For some comparisons between arguments for incompatibilism and arguments for logical fatalism, see van Inwagen 1983, Mackie 2003, Perry 2004, and Vihvelin 2008.) We will be restricting ourselves to nomological determinism, and to arguments for the claim that free will is incompatible with nomological determinism.
In his essay, “An Argument for Incompatibilism,” Peter van Inwagen concludes that free will and determinism cannot be compatible. The type of argument that van Inwagen uses, the Consequence Argument, has become the maxime popularis way for incompatibilists to assert that, determinism, and free will, are in conflict. The Consequence Argument attempts to display that, if there is an assumption that determinism is true, and then there is a further assumption that for any action that has taken place, up to a specific point, the agent never had a choice about the action taken. Then the consequence is there can be no free action of the agent. Therefore, no free will. It is my contention that van Inwagen 's argument depends upon his definition of determinism, and its reliance on this description. Subsequently, van Inwagen 's argument delivers no useful way to deduce that free will and determinism are incompatible. Arguing against van Inwagen 's thesis, I will attempt to analyze the claims he makes, and then present my arguments against these claims. Further, I will attempt to offer potential counter-arguments against my claims and then offer a conclusion that clarifies the entirety of my argument. “The main contested question,” as van Inwagen words it, is not, as is assumed, whether or not we have free will, but rather, if it is compatible with determinism. From this position, van Inwagen continues to argue that determinism and free will are