It depends on whether physicalism can account for all aspects of mind along with abstract concepts and the laws of nature (or causation). To be a successful monism, one has to be able to explain everything in terms of that monism.

Yes, and many have done so. Marvin Minsky, Steven Pinker, and Daniel Dennet come to mind. In philosophy lingo I think it all ends up being functional physicalism.

There's no consensus that Minsky, Pinker, Dennett have succeeded. Plenty of philosophers and scientists have disagreed with their arguments. Dennett's attempt rests on the controversial claim that we're actually p-zombies, and consciousness can be understood in only functional terms. This is prima facie absurd to many people.

Dennet's argument is simply an inversion of the causal chain: i.e mind is not the causer but the cause. "P-zombies" is kind of a non-starter when you think about it. I think LessWrong's essays on it shows that, here is one passage:

"you can form a propositional belief that "Consciousness is without effect", and not see any contradiction at first, if you don't realize that talking about consciousness is an effect of being conscious. But once you see the connection from the general rule that consciousness has no effect, to the specific implication that consciousness has no effect on how philosophers write papers about consciousness, zombie-ism stops being intuitive and starts requiring you to postulate strange things."

http://lesswrong.com/lw/p7/zombies_zombies/

Could you please elaborate in detail on the ways in which you feel that panpsychism fails?

I can't do it in detail, it'll take hours. From a simplicity point-of-view (Occam's razor) it adds an extraordinary claim while falling short on any evidence. Compare it to a physicalist account like Minsky, Hofstader, or Dennet where they don't require anything other than what we already know about the world.

For further reading consider LessWrong's Zombies sequence which tackles Chalmer's arguments and property dualism in general https://wiki.lesswrong.com/wiki/Zombies_(sequence)

If you could boil it down into a few key sentences, what would they be?

From my perspective WRT occam's razor, it looks quite different. If panpsychism is right, there is only one kind of matter. For panpsychism to be wrong, there has to be two different kinds of matter (conscious and unconscious), along with a mechanism to transition between the two states that is mediated by a physical process. Furthermore, despite the transition being mediated by a physical process, the difference between these two states is something undetectable to current science.

Beyond that, if you assume consciousness is the result of some physical characteristic of brains (which materialists usually do), you have to realize that most of the biochemistry going on in brains is going on all over the body. Do my organs and other body parts have their own consciousness? Furthermore, our experience of consciousness doesn't even extend to the entire brain. What is different between non-conscious parts of the brain and conscious parts? Physically the neurons themselves are basically identical. If it is the way that they're connected, those connections just change the simple physical forces acting on the particles of the brain. You again have to answer the question of how simple physical forces convert matter from unconscious to conscious.

>For panpsychism to be wrong, there has to be two different kinds of matter (conscious and unconscious)

I think you have it mixed up. Panpsychism is the dualist belief, although it differs than supernatural dualism it's still dualism. It says that matter is singular but had two properties the mental and the physical.

Whereas materialism is monist all the way through. You raise good questions and science and philosophy are still working on it but it doesn't require any extra properties or matter and agrees with scientific evidence therefore simpler.

Conscious experiences are correlated with - but irreducible to - physical phenomenon. You can say that red "is" light with a wavelength of ~700nm, but that is insufficient to communicate the experience of red to someone born blind. That is really the more important aspect of the hard problem in my opinion.

Let's assume that experience is irreducible, and you accept your own consciousness (which I hope you do!). That seems to leave a few possibilities:

1.) All normal matter is conscious 2.) Some normal matter is conscious - and we're back to the problems I previously listed 3.) Consciousness is matter/energy of a kind physics has completely missed somehow

From my perspective, #1 is the simplest, #2 is complicated, and #3 seems implausible given the fact that we've so precisely probed reality down to the sub-atomic scale.

Also, we should be careful about being overly reliant on scientific evidence. The only evidence for the existence of consciousness is your own subjective experience of it. There is no objective evidence that consciousness exists. It would seem to me that we should at least be able to prove the existence of consciousness before we make the claim that scientific reductionism can explain it.

"Liquidity is irreducible to physical phenomonon. If we break it down to atoms and look at each atom we will see that it's not liquid. Therefore we must conclude that there are two types of matter in the world, liquid matter and non-liquid matter."

Or take for example the fact that a few hundred years they couldn't figure out fire so they made up a new property (not too unlike pansychism):

"In general, substances that burned in air were said to be rich in phlogiston; the fact that combustion soon ceased in an enclosed space was taken as clear-cut evidence that air had the capacity to absorb only a finite amount of phlogiston. When air had become completely phlogisticated it would no longer serve to support combustion of any material, nor would a metal heated in it yield a calx; nor could phlogisticated air support life. Breathing was thought to take phlogiston out of the body"

The points I'm trying to make:

1. Emergent properties are real. Just saying that reducing something makes it hard to explain doesn't make that thing a magical thing.

2. History shows that it's kind of silly to invent new type of matter or properties when we fail to explain something.

We have this black box that we barely know much about inside our skulls. It could be an amazing machine that generates consciousness yet before trying to reverse engineer it some of us likes to say "it's actually not that thing, it's something else that has the magic".