d’Holbach’s Hard Determinism (in The System of Nature, 1770)

1)      A human being is a material (i.e., physical) thing.

2)      All changes in material things are determined by immutable laws (i.e., the laws of science.
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       All changes made by humans are determined by immutable laws.

1)      To be free, an action must be independent of determining physical causes.

2)      No human action is independent of determining physical causes.
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The COMPLEXITY of the sources of our actions make it impossible to say why we behave as we do in some circumstances, and this inability to identify the causes of our actions encourages the ILLUSION of free will.

G. E. Moore's attack on hard determinism 

Moore's analysis: Hard determinism is the view that if a person does x, that person never could have done other than x in those circumstances.

For hard determinism to be correct, there must be NO meaning of "could" (or "can") according to which a person could/can do other than x when the person actually did x.

Since we CAN sometimes do other than x when we actually do x, hard determinism is wrong.

If hard determinism is wrong, then soft determinism is a legitimate option. Many human actions are simultaneously free and determined by context/circumstances.

Here are three facts that show that hard determinism is wrong:

1. Even when we see that x happened, we know that a second thing, y, could NOT have happened, while a third, z, could have. And this is often true of human behavior. (This ship is going 15 knots but COULD go 20 knots, while this second is going 10 knots because it CANNOT go 15. Since we can distinguish between these two cases, the hard determinist hypothesis is false.)
2. In a certain situation, we see that a person could have acted differently by choosing differently. This fact is important, because it is our basis for assigning moral responsibility to other people.
3. Our futures are often INDETERMINATE. Because we recognize that we cannot know, in advance, that we would NOT choose something, we often make choices NOW to reduce the likelihood of making those choices later.