Will the multiverse change the scientific method?

Antony Flew

These are my last comments on Man Ho Chan’s article, which reviews and refutes recent attempts to make multiverse theories scientific. Here I’ll deal with those attempts that propose renouncing the scientific method to make the theories of the multiverse scientific. This group of proposals, the most radical, can be summarized as follows:

• Epistemological anarchy: Proposed by Feyerabend in 1988, it argues that science is an essentially anarchic enterprise: theoretical anarchism is more humanitarian and more likely to foster progress than its law-and-order alternatives. In other words: We had better give up applying the scientific method, lest we miss some pseudoscientific theory that could have been useful. 

Man Ho Chan comments this: It is doubtful that multiverse theories can make any real scientific advancement. In some versions of multiverse theories, they suggest that all that can happen happens. In other words, these versions can explain everything. If a theory can explain everything, it does not lead to any scientific advancement… Therefore, it seems that multiverse theories are passively driven by empirical findings or theoretical constructions rather than actively leading to any new scientific advancement.

Are the multiverse theories scientific?

Virgo galactic cumulus

In previous posts I have said that the theories of the multiverse (there are several, some of them contradictory to the others) are not scientific, because it’s not possible to prove them false, according to Karl Popper’s criterion: a theory is not scientific unless it can be proved false with an experiment.

A recent article by Man Ho Chan reviews and refutes various attempts to claim that multiverse theories are indeed scientific. Here I am going to speak about those that try to prove that the multiverse theories should be considered scientific without asking big changes to the current criteria. Carroll 2018 uses three main arguments to justify this:

Relativism in science?

Karl Popper

As I have said in other posts, quoting Popper, a scientific theory can never be considered utterly confirmed. In other words, we can never be completely sure that it is true. But some people try to rely on this (and on Kant’s philosophy) to reach the conclusion that we cannot know anything about reality, that scientific knowledge is relative, and that science is no different from other human activities, such as arts or fashion, whose productions cannot be said to be true or false.

Against this position, in an article published in 1990 in defense of realism, Martin Gardner wrote the following paragraph, which in my opinion hits the center of the bull’s eye:

Compatible, incompatible, possible, impossible

I wish to clarify the four concepts of the title, which are sometimes confused when talking about physical theories and their application:

• An event (real or imagined) can be compatible with a theory. In this case, if the event were real, it would not pose any problem for the theory, which admits in principle the possibility of that event taking place.

My 10 Favorite Scientific Discoveries of the 20th Century

In a post published two weeks ago, I commented on an article in Science News that tried to answer this question: which were the ten most important scientific discoveries of the last century? Some of my readers asked what is my personal opinion. This is my answer.

To begin with, I will point out that scientific research can advance in four different ways:

1. Theoretical science, which tries to discover fundamental laws in the universe.
2. Experimental science, which confirms or falsifies theories by carrying out experiments.
3. Observational science, which instead of experimenting, observes. Astronomy, for instance, uses these methods, as experimentation is almost never possible.
4. Technology, the practical application of science, whose goal is to build devices that work.

Pierre Duhem, Popper’s predecessor

Karl Popper

In a previous post in this blog, I mentioned how Karl Popper defines what is, and what is not, a scientific theory:

A theory is scientific if and only if it is possible to design an experiment that demonstrates that this theory is false.

I also said there that, according to Popper, a scientific theory can never be considered completely confirmed. In other words, we can never be absolutely sure that it is true.

After writing that post, which I published almost one year ago, I have discovered that these two Popper’s fundamental ideas had been anticipated by Pierre Duhem, to whom I dedicated the previous post in this blog.

Popper detailed both these ideas in his book The Logic of Scientific Research, published in German in 1934 and in English in 1959, both versions written by himself. Duhem, however, had anticipated them in 1913, in a letter addressed to Réginald Garrigou-Lagrange, which the latter published in his book Dieu. Son existence et sa nature (1914). By then, Popper was about 12 years old. Did Popper read Duhem? Perhaps not this letter, although other works certainly, since in The Logic of Scientific Research he quotes Duhem five times, usually to show his discrepancy. The problem is that misunderstanding Duhem is quite easy. To avoid it, one should probably read his whole work, which not everybody can do.

What’s a scientific theory

Karl Popper

Although it is fashionable to assert that Karl Popper’s theories about the evolution of science are outdated, his definition of what is a scientific theory is unassailable:

A theory is scientific if and only if it is possible to design an experiment that proves that this theory is false.

A paradigmatic case is the Copenhagen Interpretation of Quantum Mechanics. In 1935, Einstein, Podolsky and Rosen designed an experiment that could prove this theory false. A few months later, Niels Bohr published another article in the same magazine, in answer to the previous article. Almost 30 years later, as I explained in another post in this blog, the EPR experiment, which up to that point had been mental, could be carried out and confirmed Bohr’s predictions, rather than Einstein’s. As this theory was able to resist an attempt to prove it false, it must be considered a scientific theory.

Of course, this success of the theory does not imply that it should automatically be considered correct or true. Scientific theories (always according to Popper) never become so. This theory has successfully withstood an attempt to prove it false, but the next attempt could do it.