From: "Tobin Nellhaus" <nellhaus-AT-gis.net>
Subject: BHA: Levels & emergence
Date: Sat, 12 Jun 1999 09:50:56 -0400


Hi Robert--

Just a couple thoughts....

> I can't quite see that depth realism only goes one way, that is, the
> argument that you should look at the stratum under investigation and then
> look to the strata it emerged from, but bear in mind that there is a point
> at which you can't go any deeper for useful explanations.
>
> In other words, you can look to chemistry and biology to explain sexual
> attraction but there's no point in looking at quantum physics.
>
> Conversely you aren't going to be illuminated about the way society works
by
> studying from the perspective of quantum physics.
>
> There are self evident cases where the latter case MAY be futile, but how
> can you know?

I find it useful to think of "lower" levels as providing the "conditions of
possibility" for emergent levels.  Subatomic mechanics sets conditions of
possibility for chemical interactions, those set the conditions of
possibility for organic chemistry, that conditions and enables the
development of living species, etc.  But "conditions of possibility"
establish a broad range, only some of which may actually develop.  So, for
example, there are reasons on a subatomic level why life is carbon-based,
but I gather that there could be silicon-based life forms; and given
carbon-based life, there's no intrinsic reason why insects have six legs
(instead of eight, like spiders)--it's just one of the possibilities that
organic chemistry allows.

So a lower stratum can only supply certain *kinds* of explanations, in
particular the conditions upon which the emergent stratum is possible.  In
that regard one *can* go to much lower strata--if the question you're asking
is one that such strata can answer.  For instance, biochemistry won't
explain why the letters "moi" sound like "mwa" and mean "me" in French (or
sound like "moy" and mean "hi" in Finnish) ... but if you want to know how
humans are capable of hearing sounds in the first place, biochemistry is
certainly one place to go.

> Also (this may be a result of when it was written) I am at a loss to see
> where the dividing line is between the two claims:
>
> 1. that a higher stratum cannot be explained by a much lower one
> 2. that higher strata are emergent from lower (but not distant) ones

The dividing line between strata appears to be "emergent powers": the
emergent level possesses powers and susceptibilities not found at the lower
level.  Living creatures possess "life," which is not a property belonging
to chemicals or their atomic constituents.  Many living creatures develop
some sort of social organization (e.g. bees, wolves, humans)--but plenty
don't (roses, bacteria, computer geeks).  Life is a condition for social
interaction, but provides few explanations for why a social structure has
the form it has or develops in the way it does.  Biology may explain why
people desire sex, but probably not why human sexual relationships generally
involve various emotional and psychological complexities--that's a whole
different level of powers and susceptibilities.

This does not exclude the possibility that quantum mechanics explains
something about dating behavior, but once you consider the number of levels
of "conditions of possibility" involved, it should be easy to see why the
array of possibilities that quanta enable is so vast that if it actually
*does* have a specific influence on dating, it's pretty obscure and minute.

Hope that's useful.  Cheers, T.

---
Tobin Nellhaus
nellhaus-AT-mail.com
"Faith requires us to be materialists without flinching": C.S. Peirce




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