So, the basics are:
1) The mechanism for neural plasticity is more or less summed up by the Bayesian brain. It's quite heavy reading and I'm not quite sure I get all of it, but from what I can understand, the long and short of it is, the way the brain learns is to function as a predicting engine, to minimize the amount of surprises we experience. For instance, we see a physical phenomenon as a baby, like a thrown ball rising and falling back to the ground, then bouncing away. Since everything is new at first, as a baby we'd be surprised by this. As we see more of the world, we build up an intuitive set of physical laws in our head. But the thing to remember here is that the brain will try to do this in the simplest, most economical manner possible. For instance, by the time we're, say, 5, we'd know it to be blindingly obvious a thrown ball will fall back to earth, but we've no idea how to express it as a mathematical law.
So, from the moment our sensory apparatus are activated, the brain is subject to a constant stream of sensory data which builds up our understanding of the world, not all of which we are consciously aware of. The thing to remember is that, in every way, the brain always looks a little bit ahead in time an quietly tells all of our senses what to expect. If anything deviates from this, say, the experience of misjudging how many steps there are on a staircase, we get a sharp "DANGER!" signal, in the form of surprise, a brief switch into fight-or-flight mode.
2) The brain will take shortcuts. This is probably most apparent when we consider vision. There's any number of optical illusions out there which have our brain trying to shoehorn what it sees into a framework built from what it has seen. In ambiguous illusions, like the diabolical Duckrabbit below, our brain is in a little conflict with itself, trying to tell your consciousness that it sees a left-facing duck on one hand and a right-facing rabbit on the other.
Funnily enough, with a little effort, we can actively choose what we want to see, which leads me to wonder what effect our desires have on our perception. Yes, I am most certainly looking in the direction of religiously inspired hallucinations.
3) The brain comes pre-packaged with some software. Most notably, the capacity for language, as detailed by Chomsky and his Universal Grammar. More recently, Marc D Hauser, author of Moral Minds, has pushed the notion that we all carry a certain sense of Universal Morality. I've a feeling it runs deeper, but for the life of me I know not how. For instance, take phobias. I have never been bitten by a spider. No spider has ever harmed me in any way whatsoever. I've heard any number of stories from people who keep pet tarantulas that they're absolutely lovely. But when I see this:
... a part of my brain is screaming: "HOLY FUCKING SHIT RUUUUNNNNN!!!" Happily enough, I'm sufficiently in control of myself to continue this blog entry, albeit with the hairs on the back of my neck standing at attention.
Another example would be the revulsion many of us feel on encountering a cockroach. Perhaps you may recoil or grimace when I tell you that once, in a public toilet (in Malaysia, of course) while taking a leak, a whopping 2.5-inch-long roach did fly down from the ceiling, buzz around me for a bit and land next to my feet, drumming a tattoo on my left shoe with its feelers. To this day I marvel at how I managed to muster enough self-control to actually finish what I started, zip up my trousers and quietly leave the cubicle. But when you think about it, the revulsion has no real basis. I'm orders of magnitude bigger than said roach, and it is completely incapable of harming me. Even if I were to grab it and crush it in my fist (I really feel like washing my hands now) it's a mess that's easily sorted out with modern cleaning products. But even now I feel like I'd rather kill one from 2 miles away with an artillery barrage.
4) The brain has some leftover hardware. What I'm referring to here is the human's unique place in evolving on two different fronts at once, i.e. genetically and memetically. As such, urban dwellers, whose lives are more heavily influenced by memes than by genes, are sometimes led astray by hormonal urges better suited to aid in the survival of a savannah dwelling primate. And of course, some of this hardware may have something to do with the software mentioned earlier in 3).
5) Objective reality is not just an input. This is most clearly seen in the form of the placebo effect and its evil twin, the nocebo effect. In believing that an inert lump of sugar is a ground-breaking new treatment, the brain can actually convince the body that its condition is improving, a very strange case of delusion defining reality. Of course, it's a double edged sword. People convinced they're on the nasty end of a witchdoctor's curse can actually find their physical condition deteriorating.
Anyhow, that's briefly what I've got, off the top of my head (aha) re: the way the brain works. I'm-a just leave this here for now. May come back and edit this, when the mood takes me...
Oh, and before I forget, I came across a very interesting statement in Susan Blackmore Conversations on Consciousness which firmed up the way I look at the relationship between science and philosophy. I forgot who said it, and I may have put it on this blog before but I can't be arsed to check right now. What he said was something like:
Don't look to modern philosophy for answers. It has none. BUT, it has very, very good questions.
And somewhere later he mentioned that it's good old empirical science that provides the answers. It looked about right, to me.