Free will: consequence argument and various position one can takes

Is there free will?

This is probably the most important question for anyone who wants to seriously deal with some ordinary or philosophically technical issues related to free will, i.e. determinism, free will proper, moral responsibility, agency, or fatalism. This is probably the final or ultimate question we want to answer in any rate.

After Peter van Inwagen (1985)'s famous argument for incompatibilism, which is the thesis that it is impossible for anyone to have a free will in a deterministic world, it provides us with good starting point for discussing these related topics. His argument, which is sometimes called "Consequence Argument", could be stated as following:

(1) We cannot change the past history of our world.
(2) We cannot change the laws of nature of our world.
(3) Thus, We cannot change the past history and the laws of nature of our world.
(4) Every present action of ours is necessary consequence of the past history and the laws of nature of our world.
(5) Thus, we cannot change our present action. We do not have a capability to do otherwise.
(6) Thus, there is no such a thing like free will.

There have been lots of discussions since two pivotal and arguable premises are used in this argument. Each premise has its own name and they are following:

• alpha principle: if an event E occurs necessarily, then we cannot change the fact that E occurs.
• beta principle: if we cannot change the fact that an event E1 occurs and another event E2 is necessary consequence of E1, then we cannot change the fact that E2 occurs.

One can think that it is possible that there is an agents who has free will although these two premises are persuasive and the consequence argument is valid. If determinism is false, then one can be an incompatibilist (the one who thinks that it is impossible that one can have free will in a deterministic world) and, at the same time, free will realists. This position is a so-called "Libertarian".

However, there are other positions one can take. One can think that our world is deterministic and we don't have free will. Otherwise, One can think that our world is deterministic but we can have free will. This position needs to assume that free will and determinism are compatible. Finally, one can be a compatibilist, determinist and free will realist.

There is no consensus in which position is true. Free will is a very interesting and rapidly evolving field, and there are lots of multidisciplinary research involving quantum theory, neuroscience, metaphysics, philosophy of science, philosophy of mind, philosophy of action etc. This means that free will is still a important issues not only as a highly abstruse and technical problem, but also as our ordinary life's problem.