Recently, we noted a piece by astrophysicist Adam Becker at Aeon, asking whether “fetish for falsification and observation” holds back science. Essentially, multiverse cosmologists have been trying for some time to undermine basic principles of science such as the requirement for evidence and the capacity for falsification, in order to get their evidence-free theories accepted as science. Once they are accepted as official science on the basis that they somehow feel right, evidence against them won’t really matter much.
Laszlo Bencze, who has studied Karl Popper’s work in some detail, writes to offer some thoughts:
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I finally read the article referenced. It is filled with the same confusion about Popper’s philosophy of science as I have seen many times elsewhere. I don’t understand why these misunderstandings persist because Popper addresses each one of them with great diligence in his writing. Therefore, I assume that these critics have only read other people’s writings about Popper and not Popper himself.
The falsifiability criterion was only a means of separating scientific from non-scientific theories. Falsifiability does not apply to metaphysical theories. And—THIS IS IMPORTANT—Popper explains that metaphysical theories can be very useful to science despite the fact that they themselves are not scientific.
…it is a fact that purely metaphysical ideas—and therefore philosophical ideas—have been of the greatest importance for cosmology. From Thales to Einstein, from ancient atomism to Descartes’s speculation about matter, from the speculations of Gilbert and Newton and Leibniz and Boscovic about forces to those of Faraday and Einstein about fields of forces, metaphysical ideas have shown the way. — Karl Popper, The Logic of Scientific Discovery, p. 19
The quotation above refutes Adam Becker’s point:
But turning ingenuity into fact is much more nuanced than simply announcing that all ideas must meet the inflexible standards of falsifiability and observability.
Popper never said that “all ideas” must meet the standards of “falsifiability and observability,” only those which proclaim themselves to be scientific. Those which are not scientific can, nonetheless, be very important to science, as Popper makes clear.
Becker implies that the anomalies in the orbit of Uranus should have, according to Popper, been accepted as a refutation of Newtonian mechanics. But Popper would never have argued so simplistically. He would have responded that the method by which science proceeds is via conjectures and refutations (the title of one of his books). Thus, the orbital anomaly of Uranus could by conjecture be the result of a flaw in Newton’s mechanics, or the presence of another planet, or perhaps other causes more far fetched. The task of the scientist is to examine each conjecture critically with great diligence to determine if the proposed cause may be valid. Never would Popper have suggested that orbital anomalies instantly discredited Newton:
Only the first of these three ways of learning, learning by trial and error, or by conjecture and refutation, is relevant to the growth of our knowledge… — Karl Popper,
Realism and the Aim of Science, p. 4
In discussing the anomalies in the orbit of Mercury which did lead to the refutation of Newton, Becker proposes:
So Newtonian gravity was ultimately thrown out, but not merely in the face of data that threatened it. That wasn’t enough. It wasn’t until a viable alternative theory arrived, in the form of Einstein’s general relativity, that the scientific community entertained the notion that Newton might have missed a trick. But what if Einstein had never shown up, or had been incorrect? Could astronomers have found another way to account for the anomaly in Mercury’s motion? Certainly – they could have said that Vulcan was there after all, and was merely invisible to telescopes in some way.
This is silly stuff. An invisible planet? Please. The suggestion is irrational. Popper would say that critical discussion would quickly dismiss invisible planets and would focus on reasonable solutions which are subject to critical discussion:
I now come to my most central contention. It is this. The rationalist tradition, the tradition of critical discussion, represents the only practicable way of expanding our knowledge — conjectural or hypothetical knowledge, of course. There is no other way. More especially, there is no way that starts from observation or experiment. In the development of science observations and experiments play only the role of critical arguments. and they play this role alongside other, non-observational arguments. it is an important role; but the significance of observations and experiments depends entirely upon the question whether or not they may be used to criticize theories.
This, I believe, is the true theory of knowledge (which I wish to submit for your criticism): the true description of a practice which arose in Ionia and which is incorporated in modern science (though there are many scientists who still believe in the Baconian myth of induction): the theory that knowledge proceeds by way of conjectures and refutations. — Karl Popper, Popper Selections, (edited by David Miller), p. 29-30.
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See also: Question for multiverse theorists: To what can science appeal, if not evidence?
and
The multiverse is science’s assisted suicide