Re: SUO: Re: Re: Question about Example in KR Book
Jay,
Nothing is ever solved to everybody's satisfaction:
> Since you speak of 'summaries ... of observations' and mention
> Hume, I (like TJ) wonder if you are alluding (at least in part)
> to Hume's doubts about induction -- the 'justification of
> induction' problem. I don't know that this has ever been solved
> to everyone's satisfaction.
What I am claiming, however, is that Hume was attacking a strawman.
Scientific method uses induction for forming hypotheses, but that
is only the beginning. To be accepted as a theory, a hypothesis
must make testable and tested predictions about the future: i.e.,
"what will happen if". Induction, by itself, is insufficient for
realiable knowledge; predictive power is necessary for science.
To use the car example, every time that you proceed when a traffic
light is green, you are making a testable prediction about the
future: cars coming from the cross direction will stop. That
is not a prediction about physics, but about the training and
dependability of your fellow human beings. To a large extent,
people in modern societies have been so well trained that those
cases when they cause fatal crashes by going through a red light
are newsworthy events in the local papers.
Any hypothesis that has been tested by making successful
predictions about the future is a sign that it accurately
reflects some real aspect of the world. Even the traffic light
hypothesis reflects neural features in the brains of licensed
drivers -- even though we can't pinpoint exactly which neurons
cause drivers to stop for a red light.
That paper you cited is a good summary of the issues:
http://plato.stanford.edu/entries/scientific-realism/
Scientific Realism
But as the author says in the conclusion, scientific realism
actually depends on a version of metaphysical realism. I
consider scientific realism to be established beyond any
reasonable doubt, and I also consider it a sufficient support
of at least some versions of mataphysical realistm. There
are, of course, many more details to be discussed, but
they're far beyond the scope of an email note.
I would, however, like to give my short refutations of some
challenges to scientific realism that the author of that
paper mentions:
1. Theoretical entities: Many challengers, such as my arch
nemesis, Ernst Mach and the behaviorists, refuse to accept
the existence of unobservable entities such as atoms and
neural features such as drivers' habits of stopping for
a red light. I would answer that the nature of those things
might be unknown, but when people are willing to make life
and death decisions based on them, there must be something
real underlying them -- even if we don't know exactly what.
2. Kuhn's methodological incommensurability: I admire Kuhn's work
very much, and I think that his study of the paradigm shifts
that occur in scientific revolutions is important. But a tested
theory based on an old paradigm still reflects something real
for what it predicts. Newtonian mechanics has been replaced by
Einsteinian mechanics, but Newton's theories are still just as
effective as they ever were for low-speed events. They still
reflect something important about reality. Even old theories,
such as phlogiston, were accurate for many predictions, and
they also reflected something real, but we now have better
theories that give better approximations.
3. Social constructions: Post modernists argue that science is
"merely" a social construction. I agree. It is a complex of
signs, and all signs are social constructions. Signs such as
red lights are social constructions that make reliable predictions
about the future -- because they reflect something real inside the
brains of licensed drivers. Any well tested scientific theory is
a socially constructed complex of signs. And if we are willing
to stake our lives on its predictions, it passes the life and
death test of realism.
As I said before, whenever we drive a car, we are making life and
death decisions based on our predictions about Newtonian mechanics
and about the behavior of our fellow drivers. Any driver who makes
such decisions must truly believe that there is reality underlying
Newtonian mechanics and human behavior. Once you admit that such
things are real, you are a scientific and metaphysical realist.
Bottom line: Any nominalist philosopher who drives a car is either
(1) a solipsist, (2) a fool, (3) a hypocrite, (4) somebody who is
using the word "nominalist" inaccurately, or (5) somebody who has
not thought through all the issues that really matter.
John