I've noticed recently a tendency by some to attribute all that goes right or wrong with their life to chemical interactions within the brain, as if your hormones are your destiny. If you are a mindful or educated individual, you may realize some problems with that line of thinking right off the bat, but I can understand the allure of this idea for explaining away certain things in one's life that are painful to reflect upon.
Just as with all ideas seeking to refute the concept of praxis, it is self-contradictory in the barest logical sense - the very notion that you can believe that choice doesn't really exist implies a choice in and of itself. The only escape from this logical conundrum requires a type of nihilism that, if true, creates a reductio ad absurdum where any action on your part is wholly unneeded, as whether or not brain chemistry leads to 'destined' action or not is meaningless anyhow. This creates a sort of self-fulfilling prophecy of mindlessness, where you become controlled by your emotions (chemical interactions that influence preferences for acting in one way or another) as you see no benefit to using your mental faculties to restrain or embrace those impulses, leading to more or less choosing your actions by 'default' instead of with purpose.
The consequences of this strategy should be apparent, yet again, to anyone paying attention. If one has not even considered the ends they wish to achieve, how can they evaluate whether or not any given means is suitable to achieving it? This kind of existence will instead produce privation for the most part, as any action that might bring someone out of privation under this mental model will be purely accidental.
I bring this up mostly as a reflection on not only my contemporaries, but also from recently reading an interesting, if flawed account of the mindsets common to the most impoverished citizens of Great Britain. In Dalrymple's accounts, he constantly speaks of a failure in many in the "underclass" to take responsibility for any of their actions, as if Khorne suddenly possessed them before they beat the snot out of their girlfriend. Dalrymple rightly scoffs at this supposition, as those possessed of this rage seem perfectly able to control it when heavily armed police surround them. This implies, of course, that this behavior is not due to understanding and internalizing an idea I have criticized above, but rather using it as an excuse for their own failure to choose proper means for coexisting with their fellow human beings.
Of course, where Dalrymple goes off the rails is when he advocates basically jailing and beating this behavior out of them (an impulse shared by those on both the authoritarian left and right), which though a common response, has been empirically disproven as a viable method for combating behaviors one person or group views as undesirable in society. It is, however, good at murdering a large segment of the population and increasing privation in general (just as with pretty much all violence, as less hands make for heavier lifting). No, instead he should have concluded the book in a manner logically consistent with what he was seeing (and indeed advocating to his patients when he would converse with them). The recent changes in mindset for people brought about by what the Daily Bell calls the "Internet Reformation" is a far more indicitive model for what works to combat these ills in society. In fact, this line of argumentation is precisely the one Ron Paul makes in his most recent book advocating for an end to war.
With all that above in mind, I suppose what I'm really attempting to say here to all those who think that all their life is just chemical interactions on the wall of Plato's Cave is that this idea is self-contradictory and, if truly false, will actually lead you to material harm. Still not convinced? Let's make use of Pascal's wager: What is the downside to believing you can have praxis and acting accordingly, even if what you consider to be conscious action is really just an illusion? I can answer that question for you, as the answer is none.
In addition, you are likely deluding yourself if you believe your actions are caused purely as a reaction to stimulus. I see girls I'd like to bone on a daily basis, but that doesn't mean I go out and rape them, because I know that doing so wouldn't actually benefit me. Damn, how could my brain chemistry had failed to move me so! It's as if my thoughts just 'took a hold' of me and allowed me to control myself, despite what chemical signaling was telling me to do!
If there's any chemistry that is in the brain responsible for anything, it is at least that which enables you to choose to embrace or reject the chemical signals you are receiving instinctively. It is literally the key to the conceptualization of consciousness... at least the non-spiritual ones.