Richard Dawid, professor in Theoreical Philosophy

In his Spartan room at the Philosophy Department at Stockholm University there are some beautiful photos of cosmos, and you could say that this is where Richard’s philosophical passion started and where his innovative theory about scientific methodology was born. When physicists observe and try to understand our universe, it is explained by a geometrical theory of strings that all fundamental forces, nuclear, gravity, electromagnetism can be extracted from. In the last few decades, this string theory has emerged as the explanation for a microscopic theory of gravity. Many say it actually attempts to provide a complete, unified, and consistent description of the fundamental structure of our universe.

“My research focus is about philosophical questions arising from physics and string theory, especially the fact that string theory hasn’t been empirically tested and that it looks like it won’t be in the foreseeable future.”

So let us in this brief article take you on an odyssey in the philosophy of science – from the Higgs boson to Einstein's relativity theory and the big bang. And the fact that fundamental physics is entering a phase when empirical testing is increasingly difficult - something that most physicist seem to agree on. But while some physicists trust their theories without empirical testing, some others think they are no better than theology. And this is where Richards research comes in, to address the key question in the philosophy of science, how scientific theories work, what they are and what they actually claim to show. And maybe find an approach that bridges the gap through investigating the role of a non-empirical mode of theory assessment. Recently Vetenskapsrådet funded a four-year project to investigate the role of non-empirical theory assessment and the project will be carried out by Richard and one postdoc.

Predictions of physical theory

It has of course happened many times in the history of physics that predictions of a theory were not tested for a long time. There are also theories or models that haven’t been empirically testable until today. Today fundamental physics has generally entered a phase where empirical testing is increasingly difficult to achieve and often remains absent for many decades after a theory has been formulated, for example, in the case of the Higgs boson discovery. This is an example of the high degree of trust physicists can have in a hypothesis in the absence of empirical testing. The particle was discovered at CERN in 2012, but physicists were quite sure that a Higgs-Boson of some kind existed since the standard model of particle physics got empirically well confirmed in the 1980s.

“The reasons for that confidence fit within the pattern of non-empirical theory confirmation. Without the Higgs-hypothesis, the standard model could not explain the masses of elementary particles. No other theory than the Higgs hypothesis was in sight that could satisfactorily explain those masses. In addition, the standard model itself provided a very strong example of a theory that was first understood to be the only available solution to a technical problem”, says Richard, who explains that non empirical theory confirmation also can be used beyond physics, for instance in archeology or paleontology.

Justify their trust

So what Richard Dawid does is to try to understand how string theorists justify their trust in their theory and he isolates three fundamental arguments.

First the string theorists say that their theory is the only one that offers a concrete idea for a consistent explanation of microphysics and general relativity.

Second, string theorists emphasize that their theory has given them far more insights and explanation than they could expect when the basic posit of string theory was formulated. String physicists take that as a sign that they are on the right track.

Third, string theory is developed within the context of high energy physics, which has a strong record of predictive success. More specifically, high energy physics is a field where a lack of alternatives to a given theory, in conjunction with the observation that the theory explains more than what it was initially built to explain up to now, have been a good indicator of that theory’s empirical viability. This suggests that trusting a theory on this basis may make sense again.

"All three arguments of non-empirical theory assessment work on that basis and they have a more modest goal than asserting truth. What they do is to assess the theory’s chances of being successful at the next stages of empirical testing", says Richard,

And to get that scientific assessment can mean a lot for all of us that try to understand our wonderfully complex universe, and for scientists in different fields where empirical testing is increasingly difficult.

An idea that was born at Berkeley for more than a decade ago by a physicist, who became a philosopher and moved to Stockholm, could be an important piece in the puzzle to understand our universe.

Text by Eva Jarlsdotter. This interview is part of a series of interviews with faculty members ("Our Stories") of the Deparpartment of Philosophy, Stockholm University.

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