Is Evolution a Falsifiable Theory

The Rabbi’s Opening Message

Is Evolution a Falsifiable Theory

Posted on 27/2/2005

| |

Is Evolution a Falsifiable Theory

To the learned masters of debate here.

Following the exchange that developed in the thread on the eternity of the world by the Ga’avad/Ra’avad, a point occurred to me that requires clarification.

As is well known, according to the philosopher of science Karl Popper, a scientific theory is one that is falsifiable. A scientific theory cannot be proven empirically, since it is always possible that we have not yet seen an additional case in which it does not hold. However, any theory can certainly be refuted empirically, by presenting a counterexample.

For example, the theory that all ravens are black cannot be proven empirically. It is always possible that we have not yet seen another raven whose color is different (transparent, for example). But if we find even one raven of a different color, then the theory collapses completely.

It should be noted that mathematics consists of theories that are not falsifiable, and therefore it is not scientific. One cannot empirically refute the claim that the sum of the angles in a triangle is 180 degrees, for if we measure a different sum in some triangle, we will infer from this that the space in which we placed that triangle is not Euclidean. In other words, the mathematical claim is not about reality but about logic. Its application to reality is already the concern of science, not of mathematics. If someone were to claim that in our world the sum of the angles in a triangle is 180, that, of course, can certainly be refuted by measurement. Thus mathematics is not a science.

Now let us ask: is the theory of evolution (we shall discuss only the following simple and sharp formulation: whoever survives is strong, and the weak becomes extinct, and therefore species always improve over time) a theory that is falsifiable?

In my humble opinion, the answer is: no!

Explanation. The concept ‘weak’ refers to whatever does not withstand the contingencies of time; that is, whatever certain events can exterminate. Now if we claim that, as time passes, species become stronger (less weak), since the weak become extinct, then in fact this is a mathematical phenomenon, not a scientific one. In other words, evolutionary theory is an analytic claim, not a synthetic one (in Kantian terms). It contains no empirical content that can be falsified. It is a tautology: the species that endures the contingencies of time is the stronger species.

Therefore, when I read the book ‘Makor HaParush’ (Ofakim series, Am Oved), which describes an ongoing evolutionary experiment, one of the best-known in this field, I asked myself what the point of the experiment was. It is a demonstration of a necessary and self-evident process of improving the resilience of species.

I would add that whenever an argument is raised against evolution, an explanation always appears to the effect that the very trait we thought was weak actually aids survival. That is, this theory cannot be falsified, because by definition the one that survives is the strong one.

A concluding note: admittedly, one can imagine an experiment that would refute evolution—for example, if we were to see a weaker and less viable species persist after other species. But obviously that will not happen, by definition. By way of analogy: if we were to see a space that is clearly Euclidean (that satisfies the postulates of Euclidean geometry), and yet the sum of the angles of a triangle in it were not 180, then we would have refuted the geometry. But that will not happen. And if it did happen, we would assume either that we did not observe correctly or that we did not correctly apply mathematics to physical reality. And this is exactly like the refutations I described above regarding evolution, which are always dismissed in the same way—and rightly so.

Two important remarks:

1. The theory is not falsifiable, yet it is certainly correct. This is not a denigration of evolution, but an attempt to classify it (science or mathematics).

2. The basic claim is brilliant, and by no means simple or trivial. Mathematics too is not falsifiable, yet it is not trivial at all.

When I presented this question to an important professor, one of the leading researchers of evolution in our holy land, he did not understand what I was talking about. In philosophy he was apparently somewhat weaker than in evolution.

Source (forum ‘Stop Here, Think’): http://www.bhol.co.il/forums/topic.asp?topic_id=1296586