Some issues:
"As soon as either we are able to crunch the numbers to figure out what decision someone will make before they make it, or if there IS a God type being that knows all the answers, free will just doesn't make sense."
--Our ability or inability to parellel and even "peek ahead" of Determinism is irrelevant to the argument of whether Determinism is correct. I just doesn't matter what we can, or cannot do. Determinism would operate the same in either case. Our ignorance (the inability to know all the contributing factors, let alone "crunch the numbers") of Determinism gives us the illusion (false perception) of Free Will. Free Will isn't contingent on whether we can figure out all the causal connections to our actions (not decisions, since that would imply Choice/Free Will). Free Will, under Determinism, simply doesn't exist, whether we figure it all out or not. There is no way, even if we were omniscient, to get out from under the conclusion that Free Will doesn't exist, will not exist and cannot exist. There just isn't anyway to get to Free Will. "You can't get there from here", as the saying goes.
"Now, if you happen to believe in Deism and that God created the world, and just stepped back and is watching what is happening, then I believe free will is possible."
--Even this, were it true, would not get you Free Will. Since God, in this example, is operating under a "hands off" management style, Causality (an aspect of Determinism) would still be in effect and none of us would have Free Will. It doesn't matter so much HOW the universe starts, for Determinism. It's about how it operates. If there are immutable (even for God) laws of nature and if the "mind" (conciousness) is an aspect of the brain (a physical, thinking thing), then Determinism would prevail.
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In fact, Theological Determinism (separate and distinct from Determinism) argues that Yahweh (the Judeo/Christian concept of God) has no Free Will either. Let me lay it out for you:
Premise 1: Yahweh exists and He is essentially Omniscient.
Premise 2: Yahweh is Eternal. He exists at every point in time; always was, is and will be; not born of any other God. Yahweh has no beginning OR end; separate from linear time.
Premise 3: Forknowledge Assumption: Yahweh knows what was, what is and what will be.
So, how does this show that Yahweh has no Free Will? Here it is:
Yahweh's "knowing" is not the same as our knowing. What we know will happen, based on innumerable prior examples and experiences, will probably happen but doesn't have to. The example I was given was that of two neighbors. Each day, for 30 years, Bob's neighbor Jim mows the lawn every Saturday morning at 9am. EVERY WEEK, FOR THIRTY YEARS. Bob "knows" that Jim will do the same thing next week, too. Thing is, Bob doesn't know Jim will do it, but he has every reason to expect it, based on prior experience.
Now to Yahweh. If Yahweh knows something will happen, its because thats how it will happen. Remember, Yahweh is essentially omniscient and already knows how the universe plays out. Yahweh's very "knowing" guarantees something will happen since nothing there's no way it could be different, without proving Yahweh isn't omniscient. If you can show one of the premises doesn't hold true, then you aren't talking about Yahweh. You're talking about something other than Yahweh.
So, how does this eliminate Free Will for Yahweh? Because, just as Yahweh knows how everything will happen along all points of time in the universe, Yahweh also knows what Yahweh will do along all points of the time in the universe. For Yahweh to exercise Free Will and do other that what Yahweh knows what Yahweh did, is doing and will do, is an impoosibility.
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Back to Determinism vs. Free Will:
What hasn't come up much in this discussion is what is the opposite of Determinism? It's not Free Will, by the way. The opposite of Determinism is Indeterminism. The concept that instead of everything having a cause (as in Determinism), some or all actions, events, objects, etc. DON'T have a cause. They just happen. Not because God willed it, not because of anything. For no reason at all, things just happen. Does this get us Free Will? No, it doesn't. Just as Determinism doesn't allow for decisions or choices, only reactions, Indeterminism says we don't decide what to do, we just do it. Not because we want to, need to or are even compelled to. Just because. So, even the opposite of Determinism won't get you Free Will or moral responsibility. No one is responsible for anything, good or bad, because they never had a choice. Determinism says they were caused to act in a certain way and Indeterminism says we just did it, with no deliberation or causal forces or reasoning.
So, where does that leave Free Will? Nowhere. God (if God exists) doesn't necessarily have it and Indeterminism won't get it for you. To prove that will have Free Will (and that Determinism is wrong), you would have to show that our actions have consequences (causality) but that our actions--based on decisions we make--don't have any causes themselves. Roderick Chisolm took a stab at this and didn't come up with (in my opinion) a good resolution. Chisolm's argument is that we all have non-physical "Agents" (read Souls) which cause--without actually doing anything--our brains to set our bodies in motion. Everything from our brain to the final results of our actions, is called "Transuent Causation" (not transient, not a mis-spelling). Transuent Causation is pretty much like regular old Causation. Each action is caused by a previous action. No problem there. But what about from the "Agent" to the brain? What's that? It's called "Immanent Causation" (not imminent and also not mis-spelled). Immament Causation can only come from and Agent or from God. Agents can be influenced by the brain (which relays all of our experiences and sensations) but aren't "caused" or compelled by the brain to do other than the Agent wishes to do. When the Agent does make a decision, it (as said before) causes the brain to act but the Agent doesn't actually do anything. Not to the brain or to anything else. The term Prime Mover, Unmoved (a reference to one of Thomas Aquinas' reasons for the existence of God), comes to mind. Nothing actually causes the Agent to decide one way or the other, it just does--but not randomly like things do under Indeterminism. Chisolm fails to describe what these Agents really are, how they work, how they're able to cause phyiscal changes in the brain without being physical themselves. He also doesn't really explain why God and human Agents (again, not brains) are able to break the chains of causality and start new ones with every Immanent (deliberate by uncaused) act. Why does Causality apply to everywhere else in the universe but NOT to the decisions of Agents?
Anyway, that's all I've got for now.
-R.
***In the interests of full disclosure, I just finished a college course in Philosophy and wrote to "A"-graded papers on Hard Determinism (as defined by Holbach). One explained it, the other defended it from other philosophical thinkers and critics. So, I'm "hot" right now on Determinism.