Human brains are able to create certain mental abstractions. There's good evidence for why this would be useful (think about how much more flexible humans are than computer programs). Referring to these mental abstractions as "consciousness" or "qualia" is begging the question to a large extent.

The illusion is that these abstractions are evidence of something qualitatively more advanced than simple neurons interacting in a way that's beneficial for the organism. Which isn't unusual, we've seen the same kind of reaction when people proclaim that they couldn't have "come from monkeys," or any other scientific discovery that knocks humans off the pedestal they've placed themselves upon.

Why is it like something to be these abstractions?

Anthropically - whatever it would be like to be one of these abstractions is what we would call conscious.

A society of only p-zombies would call p-zombieness consciousness and they would be no less correct than us.

I wouldn't say it's an illusion; I would call it a perception, which I know exists because I do perceive it. In the same way I perceive external shapes and sounds, I perceive thoughts about those perceptions and thoughts about my previous thoughts. That's not better than Descartes, but I think Descartes had this part essentialy right :-)

There is an idea that consciousness may a mere epiphenomenon; as an epiphenomenon, consciousness cannot effect any change or action. But we have the feeling that we are choosing our action, so this must be an illusion, according to the idea.

There were some experiments in which subjects were asked to push a button whenever they chose. The results showed that the impulse to push the button arose before the subject was aware of having "decided" to push the button (I can't recall how they managed to detect and measure this).

At any rate, I think that's what the parent is referring to.

I think the feeling that we choose our actions, is actually not so clear a feeling. If you pay attention to how you actually make decisions, even simple ones, it is difficult to see where a "conscious being" played any part. You don't think your thoughts before you think them. They just arise out of the darkness of our subconscious minds and pop into our consciousness. We didn't consciously make them, or control them -- they just showed up. It seems that whatever we call consciousness, it is more of a leach that takes credit for what the subconscious animal does. To me, at best, the conscious mind is a journaler of thought, and perhaps is an offshoot of memory and our association engine.

>* You don't think your thoughts before you think them. They just arise out of the darkness of our subconscious minds and pop into our consciousness. We didn't consciously make them, or control them -- they just showed up. It seems that whatever we call consciousness, it is more of a leach that takes credit for what the subconscious animal does. *

Neuroscience actually confirms this :-) Brain scans show that conscious thoughts are reflections of subconscious processes doing all the work, AND that the rational mind is very good at creating post-hoc rationalizations for explaining "reasons" of why you arrived to the decisions you took. Most of what we call "reasoning" is about creating narratives to save our self-esteem.

If consciousness is an epiphenomenon, what was it that led Newton to create Calculus (for example). It's not clear to me how such a thing could come about via instinct.

It could just be the right kind of inputs. And I don't mean just education and such, but literally every perception Newton ever had over the course of his life, plus any genetic factors.