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:

Preceded by:  There just has to be something more, you know?  Followed by:  Physicalism: consciousness as the last sense.

Contents:  1. An epistemic difficulty  2. How and why to be a materialist

An epistemic difficulty

Like many readers of this blog, I am a materialist.  Like many still, I was not always.  Long ago, the now-rhetorical ponderings in the preceding post in fact delivered the fatal blow to my nagging suspicion that somehow, materialism just isn't enough.

By materialism, I mean the belief that the world and people are composed entirely of something called matter (a.k.a.  energy), which physics currently best understands as consisting of particles (a.k.a.  waves).  If physics reformulates these notions, materialism can adjust with it, leading some to prefer the term "physicalism".

Now, I encounter people all the time who, because of education or disillusionment, have abandoned most aspects of religion, yet still believe in more than one than one kind of reality.  It's often called "being spiritual".  People often think it feels better than the alternative (see Joy in the merely real), but it also persists for what people experience as an epistemic concern:

The inability to reconcile the "experiencing self" concept with one's notion of physical reality.

A non-materialist thought experiment.

Okay, so you don't exactly believe in the God of the Abrahamic scriptures verbatim who punishes and sets things on fire and lives in the sky.  But still, there just has to be something more than just matter and energy, doesn't there?  You just feel it.  If you don't, try to remember when you did, or at least empathize with someone you know who does.  After all, you have a mind, you think, you feel — you feel for crying out loud — and you must realize that can't be made entirely of things like carbon and hydrogen atoms, which are basically just dots with other dots swirling around them.  Okay, maybe they're waves, but at least sometimes they act like dots.  Start with a few swirling dots… now add more… keep going, until it equals love.  It just doesn't seem to capture it.

In fact, now that you think about it, you know your mind exists.  It's right there: it's you.  Your "experiencing self".  Maybe you call it a spirit or soul; I don't want to fix too rigid a description in case it wouldn't quite match your own.  But cogito-ergo-sum, it's definitely there!  By contrast, this particle business is just a mathematical concept — a very smart one, of course — thought of by scientists to explain and predict a bunch of carefully designed and important measurements.  Yes, it does that extremely well, and you're not downplaying that.  But that doesn't explain how you see blue, or taste strawberry — something you have direct access to.  Particles might not even exist, if that means anything to say.  It might just be that observation itself follows a mathematical pattern that we can understand better by visualizing dots and waves.  They might not be real.

So actually, your mind or spirit — that thing you feel, that you — is much more certain an extant than scientific "matter".  That must be something very important to understand!  Certainly you can tell your mind has different parts to it: hearing, seeing, reasoning, moving, remembering, empathizing, picturing, yearning… When you think of all the things you can remember alone — or could remember — the complexity of all that data is mindbogglingly vast.  Imagine the task of actually having to take it all apart and describe it completely… it could take aeons…