Is String Theory Science?

If it ain’t falsifiable, it ain’t science, stop wasting your time and money.

True or false? If theory can't "make contact" with empirical evidence, can it be called science? That's the question posed by some who believe that string theory, an attempt to unite the (quantum) physics of the vanishingly small with the (astro) physics of the colossally big, is not a science at all.

In "Must Science be Testable?" philosopher Massimo Pigliucci tees up a conversation on the nature of knowing, and whether philosophy (or, loosely speaking, any of the other humanities) is important to the business of physics. The question about the truth of a theory, he argues, is a question bout boundaries, distinctions that people, not just scientists, use to distinguish between competing claims.

The point is that in a lot of cases we don’t discover pre-existing boundaries, as if games and scientific disciplines were Platonic ideal forms that existed in a timeless metaphysical dimension. We make up boundaries for specific purposes and then we test whether the boundaries are actually useful for whatever purposes we drew them. In the case of the distinction between science and pseudoscience, we think there are important differences, so we try to draw tentative borders in order to highlight them. Surely one would give up too much, as either a scientist or a philosopher, if one were to reject the strongly intuitive idea that there is something fundamentally different between, say, astrology and astronomy. The question is where, approximately, the difference lies.

Similarly, many of the participants in the Munich workshop, and the ‘string wars’ more generally, did feel that there is an important distinction between fundamental physics as it is commonly conceived and what string theorists are proposing. Richard Dawid objects to the (admittedly easily derisible) term ‘post-empirical science,’ preferring instead ‘non-empirical theory assessment’, but whatever one calls it, he is aware that he and his fellow travellers are proposing a major departure from the way we have done science since the time of Galileo. True, the Italian physicist himself largely engaged in theoretical arguments and thought experiments (he likely never did drop balls from the leaning tower of Pisa), but his ideas were certainly falsifiable and have been, over and over, subjected to experimental test (most spectacularly, if a bit theatrically, by Neil Armstrong on the occasion of the first Moon landing).

The broader question then is: are we on the verge of developing a whole new science, or is this going to be regarded by future historians as a temporary stalling of scientific progress?

Along the way, the philosopher argues for a way of knowing that incorporates many different domains and, drawing on the history of science and his own domain as a philosopher of science, suggests that "falsifiable" is a permeable boundary.

"The answers are everywhere" is, of course, an idea that the IdeaFestival can get behind. Give Pigliucci's essay a read.

Stay curious™