wilkins{at}wehi.edu.au (John Wilkins) wrote in
news:blt3go$2g9t$1{at}darwin.ediacara.org: 

> Paul Gallagher  wrote:

>> Now I'm not sure I understand Sober correctly. I think he's saying
>> fitness is a real  (but non-physical) property of the organism, 
>> even if it can't be precisely measured. The analogy to temperatue 
>> is interesting, but isn't temperature precisely measurable, and
>> isn't it independent of context? 
 
> It's an analogy of ontology. Temeperature is not relative, to be sure,
> but it *is* a *physical* property that applies to differing physical
> substrates.
 
> Sober thinks, and I concur, that fitness is a physical property.
> Supervenience was proposed initially to deal with consciousness in the
> philosophy of mind - if minds were all physically different, how did
> they instantiate a physical property of - say - "seeing red" or
> "knowing that it will rain"? Jaegwon Kim proposed supervenience as a
> solution - these things can be multiply realised physically, but if
> any two physical systems were identical, they *had* to be in that
> state. 

>> Clearly there are different properties of organisms that can be
>> passed on to offspring and that can affect the properties of future
>> populations. Assigning fitness values is a way of predicting the
>> effects of these properties. But beyond that I'm confused...
>> I think it makes sense to say temperature is the cause of a 
>> physical process. But does it make sense to say fitness is a 
>> cause of natural selection?
 
> Ultimately, in each particular case (this is critical), no. Neither
> does it in each particular case of temperature.

But from a statistical standpoint it does make sense, just as from a 
statistical standpoint we can say that temperature is the cause of a 
physical process. I think it is possible to compare fitnesses - if 
individual A can run ten miles an hour, and animal B can run eleven miles 
an hour, with no other meaningful differences between them, then one can 
predict that whatever gives individual B that edge will "be selected", the 
good lord willing and the creek don't rise. Is this what Sober is getting 
at?

 What causes, say,
> paper to combust at 451°F is the binding of sufficient free oxygen to
> the carbon and other reactive molecules of the paper such that they
> release energy that causes still more molecules to so bind and release
> energy. To entify "temperature" is to run into the same problems as
> when we generalise the properties of a particular case of selection -
> say the ability of one moth morph to evade capture due to confusing
> the visual acuity of the major predator - to all cases. We note a
> similar dynamic, and we assign a variable - fitness - into which we
> pour the specifics of the physical case one by one.
 
Well, even in statistical mechanics that is the case (at least if Tsallis 
is right about the proper equation for entropy). But I can still make 
predictions based on the statistics, so even if the actual cause is 
historical the net cause is teleological.

Yours,

Bill Morse
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