The brain and the physical world in general are sufficient to explain consciousness
The problem is that they aren't, as Richard explains here.
1) In context, we're talking about consciousness as in beings which are behaviorally aware, not about subjective-experience qualia, right?
I don't understand the distinction you're making there. As I use the words, consciousness is awareness, which is experience. These are just different ways of pointing at the same thing.
2) Richard says he doesn't know, not that they aren't.
The problem is worse than merely not knowing, in the sense in which we do not know a cure for cancer. We can imagine that eventually, we will discover enough about the mechanism of cancer to devise an intervention as effective as penicillin for bacterial infection. But we cannot see, in terms of what we understand of physics and the brain, how there could be any such thing as consciousness, despite people giving the matter a great deal of thought and experimental work. That's a strong argument that they are not sufficient to explain it.
There's a tautologous sense in which they are sufficient, by taking "the physical world" to include whatever the real explanation turns out to be, but in a discussion of this issue "the physical world" means the world as understood in terms of the sort of physical theories we currently have.
On the other hand, the very close observable connection between brain states and consciousness is a strong argument that the brain and the physical world are sufficient to explain consciousness.
In short we are faced with a gigantic problem:
We are conscious.
Consciousness is very closely connected with the brain.
We cannot see how there could be any such phenomenon.
Go to 1.
A lot of discussion on the subject consists of people writing their conclusion in different words and using it as an argument for their conclusion.
I don't understand the distinction you're making there
"Behaviorally aware" is a term I'm using to talk about consciousness without invoking the "hard problem of consciousness".
The brain is a structure which takes various inputs, does a bunch of operations to them, and produces various outputs. We can see how that works, and to some extents we can make machines that do the same.
When someone's "unconscious", it means they are no longer responding to the environment (taking inputs, producing outputs) appropriately. A "con...
I've read a fair amount on Less Wrong and can't recall much said about the plausibility of some sort of afterlife. What do you guys think about it? Is there some sort of consensus?
Here's my take:
Edit: People in the comments have just taken it as a given that consciousness resides solely in the brain without explaining why they think this. My point in this post is that I don't see why we have reason to reject the 3 possibilities above. If you reject the idea that consciousness could reside outside of the brain, please explain why.