Voldie isn't like any other Legilimens in recorded history. He doesn't need to look you in the eyes, and if your shields are that rusty he'd creep in so softly you'd never notice a thing.

Harry and Quirrell spend a lot of time together, and now we learn that he might not even have to look Harry in the eyes. How much of Harry's brain has Quirrell already mapped out? Perhaps this is why he is always playing "one level above you". Maybe this is why Harry doesn't notice some things he otherwise might.

I'm going to start reading all their conversations assuming that Quirrell can read all of Harry's thoughts in real time the same way we can, and interpret all his statements in light of that. Could be interesting.

Heh. Just noticed the explicit comparison of Moody to Rorschach.

...Which is to say that whenever there is (a physical arrangement with) a logical structure that matches (is transitive with) the logical structure of consciousness - then there would be consciousness. It gets more complicated. If you draw a line with a pencil on a piece of paper, so that it encodes a three dimensional trajectory over time of a sentient being's consciousness - you basically have created a "soulful" being. Except there's just a drawn line on a piece of paper.

Assuming this is possible, I would say the line on the paper is a "rendering" or "depiction" of a concious being at some point in time. In order for the rendering to in some way "be" a concious being, would it not require the ability to change itself somehow? At very least it must be able to accrue memories, meaning that over time some part or parts of the rendering must be updated to coincide with the new memories. If the rendering cannot physically update itself, it seems there must be at least one extra part required.

It's hard to discuss further without relying on my personal definition of conciousness. But now that I think about it, I probably came up with this definition by analyzing similar ideas. Perhaps in some way specifying precise boundary conditions is equivalent to having a precise definition?

Well yes, we can clearly see that the second premise is false after some inductive reasoning.

But there's also another route, the non-inductive route: can you give me a single example of a heap of sand that becomes a non-heap when you remove a grain?

The point is not that heaps are magic or induction is broken or anything like that. The point is that humans are awful at finding the boundaries of their categories. And as Wei Dai would note, we can't just get around this by playing taboo when the thing we're supposed to be finding the boundary of enters directly into our utility function.