 |
| Hilary Putnam |
The previous
post described the no-miracles argument, proposed by Hilary Putnam. The
article ended thus:
What
do anti-realists answer to this argument? Are
they convinced?
I guess the
readers have deduced that the answer to the second question must be negative, otherwise
the debate between realism and anti-realism would have ended. Let us look,
therefore, at the answer to the first question. Faced with the abductive
argument of no-miracles, anti-realists answer in two different ways:
1.
Bas van Fraassen is an anti-realist American
philosopher who criticizes Putnam’s argument, arguing that scientific theories
are successful because unsuccessful theories have been eliminated by natural
selection (i.e. scientists have ruled them out). Therefore, asking why science
is successful is similar to asking why basketball players are tall: because
they have been selected. Let us see how Fraassen describes his theory, which is
called constructive
empiricism:
I
claim that the success of current scientific theories is no miracle. It is not
even surprising to the scientific (Darwinist) mind. For any scientific theory
is born into a life of fierce competition, a jungle red in tooth and claw. Only
the successful theories survive—the ones which in fact latched on to actual regularities in
nature.
In turn, van Fraassen's theory can also be criticized. Let us look at
the words of Anjan Chakravartty in the Stanford
Encyclopedia of Philosophy, 2017:
It
is not entirely clear, however, whether the evolutionary analogy is sufficient
to dissolve the intuition behind the miracle argument. One might wonder, for
instance, why a particular theory
is successful (as opposed to why theories in general are successful), and the
explanation sought may turn on specific features of the theory itself,
including its descriptions of unobservables. Whether such explanations need be
true, though, is a matter of debate.
2.
The second criticism to the non-miracles argument is
due to Larry Laudan, and consists in denying that successful theories are true,
citing examples of successful theories that were not true (such as phlogiston theory,
in the eighteenth century, and the ether theory in the nineteenth), as well as other
theories that were unsuccessful and are now considered true, as Wegener’s
continental drift theory. This argument is called pessimistic meta-induction, as it
tries, through a meta-analysis of scientific theories, to arrive by induction
(by accumulation of examples) to the conclusion that there is no relationship
between the success of a theory and its truth. If this is carried to the
extreme, it will try to deduce that there is a negative correlation between the
success of scientific theories and their truth, which would be an argument in
favor of anti-realism.
Realists react to this argument by redefining the success of a theory,
which would only apply to those theories that have managed to make surprisingly
accurate predictions. In this way many examples of false
theories that were successful can be eliminated. There would, therefore, be two
types of success:
·
When Newton created his
theory of Universal Gravitation, he managed to explain many hitherto
unexplained facts, such as Kepler’s laws. This would be a second order
success, for those facts were already known.
·
When Le Verrier applied
Newton’s theory to discover Neptune, it was a surprisingly accurate
prediction, for no one suspected that such a planet would exist.
Therefore, this was a true success.
 |
| Urbain Le Verrier |
Anti-realists answer that Newton’s theory failed when Le Verrier himself
tried to apply it to explain the precession of the orbit of Mercury. At that
point, the theory was wrong (or false), as it failed to explain an observed
fact.
Realists counterattack by arguing that theories are neither true nor
false, but partially true and partially false. Newton’s theory can be
considered as a pretty good approximation for the calculation of the orbits of
all the planets in the solar system, except Mercury. In the vicinity of the
sun, this theory is not true, and had to be replaced by Einstein’s General Relativity.
But the part of Newton’s theory that provides a good approximation must be
considered true. That part of the theory cannot be used as an argument to prove
that the success of the theory depends on its being false.
To this, anti-realists counterattack by making new lists of theories
that, according to them, must be considered false and successful, or true and
failures, even using these criteria. The current discussion, rather than on
issues of a general nature, is focusing on specific cases.
It is easy
to see that, in the last century, the discussion has been aggravated. Nowadays the
defenders of both positions are very active, offer good arguments, and it is
difficult to fully agree with any of them. Of course each of us tends to
support one or another position, but nobody dares to assert that there is a
clear winner.
In conclusion: this is my personal feeling, and many counter-examples
can be provided, but it seems to me that professional mathematicians and scientists
tend to be mostly realist, while philosophers of science tend to be
anti-realist.
The same post in Spanish
Thematic Thread on Philosophy and Logic: Previous Next
Manuel Alfonseca
No comments:
Post a Comment