Follow-up to There just has to be something more, you know? and The two insights of materialism.

I have alluded that one cause for the common reluctance to consider physicalism — in particular, that our minds can in principle be characterized entirely by physical states — is an asymmetry in how people perceive characterization.  This can be alleviated by analogy to how our external senses can supervene on each other, and how abstract manipulations of those senses using recording, playback, and editing technologies have made such characterizations useful and intuitive.

We have numerous external senses, and at least one internal sense that people call "thinking" or "consciousness".  In part because you and I can point our external senses at the same objects, collaborative science has done a great job characterizing them in terms of each other.  The first thing is to realize the symmetry and non-triviality of this situation.

First, at a personal level:  say you've never sensed a musical instrument in any way, and for the first time, in the dark, you hear a cello playing.  Then later, you see the actual cello.  You probably wouldn't immediately recognize these perceptions as being of the same physical object.  But watching and listening to the cello playing at the same time would certainly help, and physically intervening yourself to see that you can change the pitch of the note by placing your fingers on the strings would be a deal breaker:  you'd start thinking of that sound, that sight, and that tactile sense as all coming from one object "cello". 

Before moving on, note how in these circumstances we don't conclude that "only sight is real" and that sound is merely a derivate of it, but simply that the two senses are related and can characterize each other, at least roughly speaking:  when you see a cello, you know what sort of sounds to expect, and conversely.

Next, consider the more precise correspondence that collaborative science has provided, which follows a similar trend:  in the theory of characterizing sound as logitudinal compression waves, first came recording, then playback, and finally editing.  In fact, the first intelligible recording of a human voice, in 1860, was played back for the first time in 2008, using computers.  So, suppose it's 1810, well before the invention of the phonoautograph, and you've just heard the first movement of Beethowen's 5th.  Then later, I unsuggestively show you a high-res version of this picture, with zooming capabilities: