Add Homonym: Perhaps it's the Flying Spaghetti Monster that's responsible? (j/k)
Anfauglir: At what point does something that seems like an illusion or a fiction stop being so? Let's say we have a person who's fundamentally selfish - who only cares about himself and things insofar as they pertain to him. This person ultimately only wants a comfortable life where they can do things because they're desirable, rather than simply necessary, so they act in a relatively unselfish manner in order to advance themselves and their own desires. At what point does the pretense of being a decent person become the reality?
Yes, you can argue, quite cogently, that it's all just subatomic particles at base, and that any sense of free will or self-determination only springs from within the mind itself, rather than coming from the basic structure of the brain, the web of binary pathways that serve only to transmit electricity. Neurons don't have self-determination, they don't decide whether to transmit electrical signals or not, they depend on input from outside (neurotransmitters) to do so. And those neurotransmitters also don't decide whether they want to be sent. The problem is that we can't really follow that chain all the way from the bottom to the top, because we don't truly understand just what the consciousness is, let alone how it works within the context of the brain.
What that means, ultimately, is that any conclusion we might draw from our current observations is at best incomplete. And it could be wrong, or even misguided, not due to any deliberate intent, but simply due to the dearth of conclusive knowledge that we use to make those conclusions in the first place. There's several hypotheses regarding the consciousness, such as the [wiki]quantum mind[/wiki] hypothesis. It's based on the premise that classical mechanics simply don't explain the nature of consciousness and that we need to look at quantum mechanics to come up with a theory that explains things properly. For example, if the consciousness does use things like quantum entanglement and superposition in order to function, then a purely deterministic model of the consciousness is akin to Newtonian physics - correct as far as it goes, but simply not capable of explaining certain things which would radically change our understanding of the overall system.
It's true that these hypotheses are in need of further work. For example, with the quantum mind hypothesis, we have the problem of how the brain would keep its own quantum states from decohering before they became useful for neural processing. It's possible that it, and other hypotheses that attempt to explain consciousness, may simply not work as viable explanations. In the meantime, I'm not suggesting that we should make unwarranted assumptions about self-determination, or that those skeptical of it should accept it simply because it's appealing. But neither should we act as if the deterministic relationships that we currently understand are the be-all, end-all of reality. If nothing else, we've shown that self-determination does exist, even if it's subjective in nature. That subjectivity wouldn't make it any less existent than, say, a personal preference for vanilla over chocolate, since we can't really tell everything that makes someone prefer something over something else.
Well, that's my point. Self-determination may 'only' be an illusion (though I do not consider it to be so), but technically, the reality we experience is itself is an illusion. The sun shining outside the window, my fingers tapping the keyboard as I write this - it's ultimately nothing more than the interaction of electromagnetic forces. It's all just an illusion that we experience because of the limitations of our senses. Yet, for us, the illusion is what's real. Similarly, self-determination may be nothing but an illusion, but for all intents and purposes, it's part of our reality.