Causal determinism states that every material event is necessitated by antecedent events and conditions within the framework of the laws of nature. Free will is broadly speaking the capacity to control one’s actions. The philosophical debate on free will is about whether or not causal determinism is compatible or incompatible with free will. Incompatabilism is the view that causal determinism and free will are incompatible and that since causal determinism is true, free will does not exist. I shall assume that when Molyneux refers to ‘determinism’ he is referring to ‘incompatabilism’. Given this let us turn to Molyneux’s main argument against determinism which I shall refer to as ‘the preferred states argument’.
To quote Molyneux’s most succinct statement of his argument against Determinism.
“A system without free will cannot have preferred states.
Determinists argue against free will.
Determinists propose preferred states. (determinism is true, free will is an illusion, truth is infinitely preferable to falsehood, etc. etc.)
Thus determinism fails.”
There are two problems with this argument. Firstly, premise (1) is false if we take Molyneux to be using ‘preferred states’ in the descriptive sense of so and so prefers x to y. This is because if incompatibilism is true descriptively people have preferred states but they do not have free choice over the states they prefer. For example I may have the mental state of preferring chocolate over bananas but I do not choose to prefer chocolate over bananas, rather I was determined to. This preference is analogous to the preferences of non-human animals who are usually thought to lack free will e.g. we may say that a lion prefers cat nip over celery even though the lion was determined to do so.
Secondly, the behaviour of individuals when arguing for incompatibilism seems to be of little relevance to the truth or falsity of incompatibilism. If John says to Joe ‘free will is an illusion’ either John has free will and so chose to say such sentences while if incompatibilism is true he was causally determined to utter these sentences. But him uttering these sentences has no bearing on which explanation is true. Either he chose or was determined. Likewise either he chose to act as if free will is true or he was determined to act as if free will is true. So it seems that Molyneux’s argument is just restating the problem of which explanation is correct. At worst Molyneux seems to believe that if one acts as if other individuals can freely choose to believe in something then it is not the case that one cannot freely choose anything. Which is false since how an individual acts and the implicit beliefs an individual acts on are distinct from what is actually the case e.g. a person can act as if God exists but that does not entail the existence of God, or one can act as if David Lewis’ theory of modal realism is true but that doesn’t suddenly make it the case that all possible worlds are as real as the world we are currently in.
It is because of these two problems that we should charitably re-interrupt Molyneux to be using ‘preferred states’ in a normative sense of ‘so and so ought to prefer x to y’ and take his argument to be an attempt at concluding that we should reject all arguments for incompatibilism and not the claim that incompatibilism is false. This results in the following formulation:
1. A deterministic universe lacking free will cannot contain objective normative statements of the form ‘so and so ought to prefer x to y’.
2. Incompatibilists argue against free will and in favour of a deterministic universe.
3. In arguing against free will incompatibilists propose preferred states e.g. you should believe in incompatibilism and so prefer the doctrine of incompatibilism to the doctrine of free will or you should prefer truth to falsity and so believe what is true.
4. Given 1-3 in order to argue for incompatibilism incompatibilists must act as if incompatibilism is false and free will is true.
5. An argument which in order to be made requires one to act as if the negation of the argument’s conclusion or premises are true is a self-detonating argument.
6. We should reject all self-detonating arguments.
7. Given 4-6 we should reject all arguments for incompatibilism.
8. If we should reject all arguments for incompatibilism then there is no reason to believe in incompatibilism, even though it may in fact be true.
The problem with this argument is that it is only convincing if we first assume that incompatibilism is false and free will true. If we accept premise (1) it follows that if incompatibilism is true there are no objective normative facts and if incompatibilism is false and free will is true then there are objective normative facts. But premises (6) and (7) are normative statements. For example (6) is the normative statement that we should prefer non-self-detonating arguments over self-detonating arguments. The premise is only objectively true if incompatibilism is false and free will is true. Yet (6) is a premise of an argument against incompatibilism and so in order for the argument’s premise to be objectively true, one must at least assume that incompatibilism is false. The argument therefore assumes that incompatibilism is false in order to conclude no arguments in favour of incompatibilism are convincing. Given that this is a mere assumption an incompatibilists can simply deny the assumption and so have no reason to draw Molyneux’s conclusion. In order for the argument to be convincing Molyneux must first offer a persuasive argument for the conclusion that incompatibilism is false and free will is true. But if Molyneux does this there would be little reason to make the ‘preferred states argument’ in the first place because we would have an argument for the far stronger conclusion that incompatibilism is false.
Molyneux could restate the argument as follows:
(6) self-detonating arguments are invalid
(7) invalid arguments are unconvincing
(8) Therefore all arguments in favour of incompatibilism are unconvincing
This is problematic because premise (6) is false since self-detonating arguments are not logically invalid. For example, the argument ‘all sentences of a language are meaningless’, ‘p is a sentence of a language’ therefore ‘p is meaningless’ is a self-detonating argument for Molyneux because in order to say that language is meaningless one must act as if language is meaningful. Despite this the argument is logically valid because the truth of the premises guarantee the truth of the conclusion.
A further reformulation may be:
(6) Self-detonating arguments are not convincing
(7) Therefore all arguments in favour of incompatibilism are unconvincing
However even if we accept this reformulation as unproblematic it at best follows that Molyneux has shown that any argument for incompatibilism which includes or relies upon normative preferred states is unconvincing. But his argument does not show us that all arguments for determinism which contain or rely upon only descriptive premises are unconvincing. Thus an incompatibilists can easily escape Molyneux’s conclusion by simply never stating or implying that other individuals ought to believe in incompatibilism. Rather they can simply state that incompatibilism is true in a purely descriptive sense and argue for it using only descriptive premises which do not rely on any normative premises.
Moreover, an incompatibilists could even include in their argument the statement of the fact that they hold a normative belief. For example the statement ‘I believe you should be a incompatibilists’ is merely the description of one’s mental states and so is not ruled out by incompatibilism being true if incompatibilism entails that there are no objective normative facts. All that follows is that I was determined to believe that you should be a incompatibilists. This is true even if I think that you ought objectively to be a incompatibilists since I am not stating that ‘you should objectively be a incompatibilists’, only that ‘I believe that objectively you should be a incompatibilists’. The latter is self-detonating since it requires one to act as if objective normative facts exist and so act as if incompatibilism is false, while the former is not self-detonating because it only requires one to act as if it is descriptively true that one has a certain belief.
To conclude, Molyneux’s ‘preferred states’ argument against incompatibilism is not convincing, despite several very charitable reinterpretations and never taking the notion of ‘self-detonating arguments’ to be problematic.