He cannot act better, or worse, if he has no free choice. He simply acts how he was already determined to act. In a universe without free choice (whether you arrive at that universe via religion or determinism) all choice is an illusion.
I think that caveat is a big one; namely, there are situations which are completely deterministic (as in, evolving according to a fixed set of rules in one possible way), yet nevertheless are intrinsically unpredictable, by anything other than effectively setting up the system and seeing how it evolves. So I think that predictability is sufficient (anything that is perfectly predictable is also deterministic), but not necessary (there are things that are unpredictable, but still deterministic).
People always get all worked up about quantum mechanics; let’s think special relativity for a change. Rietdijk originated an argument basically amounting to noticing that for any event, special relativity posits that there exists an observer to which that event is already in the past, in the same way that ‘five minutes ago on the sun’ is in the past to us; so if you believe that what happened five minutes ago on the sun is fixed, then you also believe that the universe is deterministic. This is sometimes more fancifully framed in terms of aliens from Andromeda invading Earth: if they hold council on whether or not to invade on Monday, and start their invasion fleet on Tuesday, there exist two observers here on Earth, say, one stationary in the street, the other driving past him, whose present moments (their hyperplanes of simultaneity) coincide with the invasion-council and the launching of the fleet, respectively. But if to one observer, the fleet is already on its way, to the other, the decision of whether or not it will be sent can’t be up in the air, and must be fixed!
Thus, special relativity seems necessarily to lead to determinism.
That doesn’t make sense. My tomato plants can act better or worse as a response to stimulus. Of course a human can, as a response to stimulus.
It doesn’t matter how much we like it or don’t like it. The only thing that matters is whether or not it’s true.
Er, we are still talking about determinism, right? Because you have me confused. Your actions are either pre-determined or they aren’t. Stimulus has nothing to do with it, other than being just another thing that is pre-determined.
Stimulus is predetermined, AND it has everything to do with it. There’s no contradiction there.
It’s interesting. Do you think that if a criminal defendant could claim that his exact “state of being” lead him, inexorably, to rape, than we cannot prosecute him?
My “sense of justice” & “right & wrong” force me to want to hold the defendant accountable for their actions.
This lump of chemical reactions [me] struggles to manipulate it’s enviornment to achieve a more pleasant seeming set of conditions, and refuses to accept things as they are. 
The Universe oppresses me.
I think this is the crux of it - whenever I come across conceptual Philsophic questions, I pause and consider “is answering THAT question helpful?”
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At some level, our “system” of existence is unknowable - if you need a cite, per Godel. So, at some level, looking for a definite answer is more of a statement of hubris than a true appreciation of the underlying reality we are experiencing
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On a practical, everyday basis, you are playing the role of actor - you can call this Free Will or whatever, but you act in your life.
On a practical basis, I believe we behave in Deterministic ways - we tend to behave like the animals we are (Nature) and like the social beings we are (Nuture). Those tendencies lead to an implied Spectrum of Options we are far more like to consider for any action, but on a practical basis, we still act in our lives to choose amongst those options…
So you can’t change anything, but believing you can changes things?
Things can’t be other than they will be. If you believe you can change things, they will be better than if you believe you can’t change things.
…and what could be more important than positioning yourself as an actor within the context of your life?
I always struggle with the need to discuss this question past that point. It’s a nifty concept to noodle, but on a practical basis, beyond that, who cares?
Well, there are two problems with this. One, you seem to suggest that we can choose what we believe, the truth of which is not at all obvious. Clearly there are some things that we can’t choose to believe: I cannot choose to believe that Chicago is the capital of Illinois, when I know it is Springfield. If I were to choose to believe that all my grandparents were still alive, in order to make me happier, that would be indicative of a mental illness.
Two, if things can’t be other than what they are going to be (in the sense that the initial state of the universe plus the laws of nature wholly determine every subsequent state of the universe), then there doesn’t seem much point in asking someone to believe something. They will either be destined to believe it or not, just as you were destined (or not) to ask them to believe it. If you take determinism to all its logical consequences, we become observers in a great cyclorama, merely spectating as the laws of nature play out around us and in us.
I’m claiming you can’t really choose anything at all, much less what you believe. You can, however, be convinced of a certain belief, which is different from choosing it.
If I try to persuade them, sure, it’s because I’m predetermined to try to persuade them. Nevertheless, I act like I have free will, because that’s how I experience the word (however illusory that experience may be), and because I find that leads to better results than acting as though I don’t have free will.
Those two points go together inextricably. Because I experience the world as though I have free will, I experience everything as a choice. I experience a choice about whether to act as though I have free will or not, even if that choice is illusory. When I experience that choice, I end up acting as though I have free will.
Yes, that result is predetermined. But that’s not how I experience it.
If I act as though I’m a spectator, I find that my life sucks a lot more.
Fundamentally, **LHoD **appears to be stating that we are better off if we position ourselves as actors in our lives. Extrapolating that to *reductio ad absurdum *examples beyond that would therefore be sophistry.
Rod Blagojevich could.
Well, can you blame him? 
Haha, j/k, I love the SPI.
If you can choose to be a determinist, then that’s reason enough not be one.
I’m not - the universe is stochastic at a much coarser level than that.
Do you want to provide an argument for that, or are we just going to have to accept your word for it?
Also, what do you think about Rietdijk’s argument?
I hear that sort of argument a lot as a reason why we shouldn’t believe in determinism*. I take the opposite view; if the accused man’s “exact state of being” didn’t lead him to rape, then we shouldn’t punish him at all. Why bother, since it wouldn’t make any difference? Crime and punishment is based on a deterministic view of human nature and the world, that a particular stimulus and a particular action will have a predictable outcome. If his past self doesn’t determine the actions of his future self, then nothing we do in the past will modify his future behavior.
*Which by the way amounts to a claim that we should believe a lie; if we decide to believe in “free will” regardless of the evidence, that’s what we are doing like it or not.