Hypothetically, science proves free will isn't real

[Ignorant]

Only if there is not only one physically possible future. If there is one physically possible future [1] then either (a) or (b) is determined to be taken and the other is an illusory option. [2]

I'm confused. If determinism is true there is no "could have been obtained instead". If determinism is true there is only one possible future.

This illustrates how unhelpful the artificial boundaries of the determinist/compatibilist argument have become.

1) This is the case if a person is actually in the presence of determining conditions. I am asking you to consider the potential of a human agent in the hypothetical abstract, free-from-condition sense. If you care to engage in that thought exercise, then we can move on to:

2) Given hypothetical conditions (x) surrounding person (I), only action (a) will obtain through the agency of person (I).

Given hypothetical conditions (y) surrounding person (I), only action (b) will obtain through the agency of person (I).

If that is true, either action(a) or action(b) IS ABLE to obtain through the agency of person(I), depending on the surrounding conditions. If that is true, the agency of person(I) IS ABLE to bring about action(a) or (b) depending on the circumstances. In other words, person(I) is the sort of thing able to do action(a) or (b).

That means that person (I) can do either (a) or (b) (they have the intrinsic power to do so) but the ACTUAL doing of one or the other depends on circumstances. Given circumstances(x), action(a) obtains WHILE THE POTENTIAL FOR ACTION(b) REMAINS WITHIN THE PERSON.

This is simple contingency vs. necessity, which the modern debate conflates with non-coerced choice vs determinism, respectfully.

Everyone has the ability to push 3 different buttons... no one is denying that, that's trivially true.

Ya, I know it's trivially true. So why is it not so evidently and trivially true in the moment only one button is pressed? When a person presses a red button, did they lost the ability to press a blue or green one?

The real question is why do some people mistakenly believe they not only could have pushed otherwise but that they could have willed otherwise?

Because the discussions like this one don't care to distinguish concepts properly. The 'willing' is a possible determining factor of the pushing. Whether or not the 'willing' is an ACTUAL determining factor in bringing the action about is irrelevant to the separate but important question regarding the logical potential that the action has at all.

1) Suppose X => Y in a way which is not conditioned by any external influence. If that is the case, then there is no set of circumstances in which X does not => Y. If that is the case, then X => Y happens necessarily.

2) Now suppose that X => Y in a way which is conditional upon the simultaneous Z => X. If that is the case, then in the absence of Z, X does not => Y. If that is the case, then X => Y happens contingently. 

If human action is more like 2, then any determined human action (it doesn't matter by what/who the action is determined) happens in BOTH in a determined AND in a contingent manner.

Does this say anything about the nature of 'willing' or its place in determining action? No. You can't even begin to approach that question until there more fundamental distinctions are made.

Necessity as distinguished from determinism

Contingency as distinguished from choice or options or freedom etc.

Determinism means you could neither have willed nor done otherwise.

Indeterminism means you could have done otherwise but you could not have willed or freely chosen otherwise.

That seems like an unhelpful way to define this idea. 

Determinism means you could neither have [determined to do, or in fact done, otherwise].

Indeterminism means you could not [have determined otherwise, but you could have done otherwise].

Wouldn't this be better:

Determinism means that everything but you determine human actions.

Indeterminism means that nothing determines human actions.

Better still:

Human determinism means that both the observed environment and personal rational operations contribute to the determination of human action within that environment.

Cosmic determinism means that there is no personal human contribution to the determination of human action

What is not trivally true or true at all, is the ability to will otherwise. If determinism is true, we could not have done otherwise. If determinism is false, we could not have willed otherwise, there isn't even any cause and effect.

See above. How can we talk about the 'will' as a potential contributor to determining action when we haven't even agreed on how to talk about those actions in the first place?

If I am able to do A or B, I may do A even while retaining the 'ability' to do B. <= Contingency, irrelevant to the reality of determinism vs. indeterminism

If I am able to will A or B, I may will A while retaining the 'ability' to will B. <= Still contingency, irrelevant to determinism/indeterminism

If I am able to will A or B, what contributes to my 'willing' A rather than B? <= Different question entirely relevant to determinism/indeterminism

The point is intentional and voluntary actions do exist, and if that's all free will is, then there's no question it exists. It's trivally true. 

It doesn't seem so trivial when you are the person getting intentionally stepped on. That things happen in a deterministic sense does not mean that they happen in a necessary sense. 

Your whole imaginary discussion (which I enjoyed) ignores that problem.

A gun to the head is an example [of coercion].

Are external determining influences coercion?

It's a lot easier to say "compatabilism" than to say "the view that free will is compatabile with determinism" considering the amount of times I am going to have to mention if when we talk about this.

I am saying that the compatibilism vs. determinism discussion inherits and ignores conflations and equivocations which ultimately perpetuate the discussion indefinitely. The concept of necessity is rolled into determinism and the concept of contingency is rolled into choice and freedom. An action cannot occur as necessary and contingent at the same time. An action CAN occur as determined and contingent at the same time. See the problem?