[inigyou]

We can't even see an electron. But we can see the effect of a beam of electrons on a low-pressure gas quite easily.

We can't even see a table. We can only see the nerve impulses resulting from the photons resulting from the sunlight bouncing off the table.

A computer can't play sound either, it can only send bits to a DAC.

[podocarp]

That is true. I'm not arguing for that standpoint, but it works perfectly fine for all classical matters and has been since Descartes.

I think in a common sense way you do get what I mean though when I say it is obvious that when we see two billiard balls colliding we know it but when think of electrons colliding it is only indirectly through whatever happens after the collision, never the process itself.

[inigyou]

We saw the things that were easy to see long ago. Now we're seeing the things that are harder to see. That is, of course, harder, and more complicated, and only gets worse as we probe deeper, with more and more indirection, but I think all the stuff we are seeing has a pretty good grounding so far that it's actually something we are seeing indirectly and not a model artifact, at least until you get to quarks and gravitational waves, and we definitely can't see the strings of string theory.