I recently read an article by a philosopher who stated that physicalism must be false or at least incomplete because it doesn't adequately account for experience. For example, say you knew all the physical information involved in seeing a sunset, even if you convey all that information to a person you'll never actually describe a sunset. Say you know a blind woman (since birth) and she asks you "what's it like to experience a sunset?", do you go off saying well it's a wavelength hitting the photoreceptors in your eyes which send electrical signals to your brain, even if that's true she's still no closer to understanding what experiencing a sunset is like. The point being that you can't reduce experience (or qualia) down to purely physical information. Personally I agree that it's impossible to describe experience with just physical information, even with something as simple as the smell of an orange, you can only communicate a description of what the smell of orange smells like tautologically, i.e. "it...

One way to understand the basic argument you outline, which is advanced most famously by Thomas Nagel in "What is it like to be a bat?" and Frank Jackson in various papers about Mary the color-blind super-scientist, is like this: 1. If physicalism is true, then someone who knew all the relevant physical facts about a conscious being's experience (e.g., a bat or a person seeing red) should know what it is like to have those experiences without having had them (i.e., without experiencing sonar perception or without having seen red). 2. Someone who knew all the relevant physical facts would not know what it is like to have those experiences. 3. So, physicalism is false. I think there are good reasons to reject both premises. Premise 2 looks like an appeal to ignorance. It does seem implausible that any amount of objective (or 3rd personal) information could allow someone to understand conscious experiences she has not experienced. But we do not really know what a physicalist theory of...