From: louis_irwin-AT-mail.fws.gov
Date: Thu, 10 Jul 97 17:08:12 -0700
To: <bhaskar-AT-jefferson.village.Virginia.EDU>
Subject: Re[2]: BHA: metaphysical refutation



John Game wrote: "I was suddenly worried by the possibility that 
Bhaskar solves the problem of induction at the expense of being able to 
explain predictions that scientists DO actually make. ... But if one 
looks at the practice of science at least since the mid-nineteenth 
century they have in reality departed from Laplacian determinism as a 
model and have tended to argue that it is not necessary to control 
every variable to make a prediction.  It doesn't seem to me to be 
entirely possible to argue that at least in applied science those 
predictions have been merely statistical. This would be very important 
for an astronaut for example. How do scientists do this in what are 
open systems?"

That is a very good point to consider.  Predictions are an essential 
part of science, both in closed and open systems.  Predictions must be 
possible in open systems, because they are successfully carried out all 
the time.  One way of making predictions is, as you say, controlling 
variables, however notice that in controlling variables one is making a 
system less open.  Another way of making predictions is by ignoring 
uncontrolled variables that are know to have minor effect.  Here one is 
saying the system is closed for all practical purposes.  It is 
important to contemplate the role of engineering in both of these 
methods.  Planes fly because they have been engineered to control 
certain variables and to be able to ignore unpredicted meteorological 
changes. 

"(just to anticipate I take on board the argument about celestial 
objects being different from more close at hand objects although this is 
in itself puzzling; one can think of other examples)."

There is an interesting point about the nature of closure in relation to 
celestial systems.  Even if the solar system, say, were completely 
isolated from the rest of the universe (nothing would ever cross some 
border around it), the solar system would not thereby be a closed system. 
I think this might surprise a lot of people, but it is quite obvious when 
pointed out.  Consider just quantum phenomena occurring within the solar 
system; since they are unpredictable, their existence assures the solar 
system is open.  Or consider the future; if you think the future is open 
then you can't think the solar system is closed.  One can think in terms 
of a system being closed with respect to some phenomena.  A system is 
then closed if it is closed with respect to all phenomena.  The 
deterministic equations of field theories in classical physics apply to 
systems that are closed with respect to their phenomena, but they imply 
nothing about other phenomena which can interfere.  Notice the conceptual 
phenomena of saying a system is closed with respect to all phenomena.  
How can one delineate in advance "all phenomena"?  That is a problem 
which a Laplacean has to ignore and which a critical realist does not 
have to worry about.

I hope this restores equilibrium to your philosophical universe.

Louis Irwin




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