What is free will? (include in your discussion determinism versus indeterminism, moral responsibility, compatibilist theories of free will and the could-have-done-otherwise principle, the science of free will and free will in Theology).
Free will is the philosophical doctrine that our choices are, ultimately, "up to us". Consequently, an unfree action must be somehow "up to" something else. The phrase "up to us" is vague, and, just like free will itself, admits of a variety of interpretations. Because of this vagueness, the usefulness of the concept of free will is questioned by some. We can ask several logically independent questions about free will.
This discussion includes the following topics related to the free will debate:
1 Determinism versus indeterminism
2 Moral responsibility
3 Compatibilist theories of free will and the could-have-done-otherwise principle
4 The science of free will
5 In Theology
Determinism versus indeterminism
Determinism holds that each state of affairs is necessitated (determined) by all the states of affairs that came before it. In other words, what happens next is completely fixed by what came before and could not be otherwise. Indeterminism is the denial of determinism, and implies that some events were not necessitated by the previous states of affairs. In other words, what happens next is not completely fixed by what came before. The idea of determinism is sometimes illustrated by the story of Laplace's demon, who knows all the facts about the past and present and all the natural laws that govern our world, and uses this knowledge to see the future, down to every detail.
Some philosophers hold that determinism is at odds with free will. This is the doctrine of "incompatibilism." Incompatibilists generally claim that a person acts freely (has free will) if and only if the person is the sole originating cause of the act and the person could actually have done otherwise. This kind of free will is incompatible with determinism. If determinism is true, and everything that happens is completely determined by the past, including events that preceded our births, then every choice we make would ultimately be determined by prior events that were not under our control. Our choices would be just another outcome determined by the past. So if determinism were true, then we would be trapped by the past and free will would be an illusion. "Hard determinists", such as d'Holbach, are those incompatibilists who accept determination and reject free will. "Libertarians", such as van Inwagen, are those incompatibilists who accept free will, deny determinism, and instead believe that indeterminism is true. (This kind of libertarianism should not be confused with the political position of the same name.)
Other philosophers hold that determinism is compatible with free will.
These "compatibilists", such as Hobbes, generally claim that a person acts freely if and only if the person willed the act and the person could (hypothetically) have done otherwise if his or her will had been otherwise. They often point to clearcut cases of someone's free will being denied --rape, murder, theft, and so on. The key to these cases is not that the past is determining ...
Several perspectives of the free will debate are detailed e.g. determinism versus indeterminism; moral responsibility; compatibilist theories; science and theological perspectives. Supplemented with an article on free will.