Re: reification

[Joel Rauber <Joel_Rauber@SDSTATE.EDU>]

Leigh and friends (affectionately known as the phys-L gang)

> I don't see what you mean here, Joel. What insight do you gain by
> reifying entropy? It is just a number that you calculate formally,
> and it is no more nor less real than energy. How does it help you
> to treat it as a thing?

I'm guilty of neologizing the word 'reify' and its "nearest neighbors, e.g.
reification.  It is a bad habit.  In the context of my example, I meant it
as an example of taking a mathematical model, an expression for surface area
of the event horizon of a black hole; and noting its analogy to the 2nd law
of thermodynamics.  Then "reifying" that analogy and treating it as if it
really is an example of the 2nd law and entropy.

So I guess I'm not literally saying that I have reified the concept of
entropy as a concrete object (as you point out above); but rather I'm
"reifying" the law of black hole event horizon area, as an example of the
2nd law.  (hence the neology).

A further point I'm trying to make is that reification is not an "evil" word
(like "heat").  I think that that is what a *model* is; its a reification
something that isn't the actual object.  see comment below; and I'm stopping
here before I slip into a state of solitary solipsism.

I view looking at hole transport in semi-conductors as being a useful
reification.

> > When I consider the ideal gas model, I really do assume the gas is
> composed
> > of little teeny tiny hard-non-interacting BB's rattling around in a
> > container.  I'm forced to do this to check for
> self-consistancy in the
> > model.  I fully realize that the model isn't the actual object.
>
> In that case you are not reifying it; that was the point.

Actually I think the above is the essence of reification.  My Websters (not
the best of authorities) defines 'reify' as

reify = to treat as substantially existing

I maintain that that is exactly what I'm doing when I think of an ideal gas
as being teeny weeny hard spheres; and when I model a real gas as an ideal
gas.

> > I like the quote, and reluctantly admit to being trained in
> theoretical
> > physics; which may explain a few things.
>
> This is a tolerant group; we won't hold you resposible for such
> shortcomings.
>
> Incidentally, Bill Unruh is an old friend of mine across town at
> the University of BC. I think he's the fellow who first got the
> idea of associating the area of the event horizon with the entropy.
>
> Leigh

I'm not entirely sure of the entire history of this idea, but I recall a
graduate student by the name of Jacob Bekenstein as being the originator of
the speculation of relating the event horizon area to entropy.  I've now
forgotten where he was located at the time, but Princeton springs to mind.
Was Unruh a post-doc there at the time (1972 or a few years prior)?

I once asked Unruh for a post-doc position; considering there was none
advertised at the time, I wasn't surprised to be rejected.  It would've been
nice to have parked in Vancouver for a while.

Joel