Thursday, March 14, 2019

Anti-realist answers to the no-miracles argument

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

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