On the third day of HowTheLightGetsIn, the Arena was buzzing with those brave souls wishing to see the clash of titans over string theory. An extraordinary panel: Nobel Laureate Roger Penrose, pioneering string theorist Tasneem Zehra Husain, Polymath Mathematical Physicist Eric Weinstein and the ground-breaking string theorist Brian Greene. The panelists gathered at HTLGI to debate the trouble with String Theory, theory or framework, community or oligarchy, a beautiful theory or one detached from reality.

String theory, heralded as a potential theory of everything, has dominated theoretical physics for over thirty years, with more scientific papers arising from it than any other theory. But critics argue the theory has held undue influence and proclaimed that it is an error to pursue it. String theory proposes 11 dimensions and a vast landscape of possible universes without any evidence. Moreover, a theory of everything has not been forthcoming, and predictions of supersymmetry particles have not been confirmed.

The distinguished panel came together to discuss whether it’s time to move on from string theory, recognise that the search for supersymmetry has failed, and seek alternative accounts of the universe supported by observation and experiment. Penrose and Weinstein argue we should see it’s mathematics, without any connection to the physical world, as little more than fantasy. Whereas Greene and Husain state that the continued power and allure of string theory is justified by its potential to unify our understanding of the universe once and for all.

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Presumably given that scientists themselves want to be correct they will pursue ideas they think will lead them to the truth

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Roger Penrose kicks off the debate by arguing that whilst initially intrigued by this theory in the 1980s its need for 26 dimensions including time was too far at odds with the obvious fact that we live in a 4-dimensional world that includes time. Whether or not you think this is a powerful enough objection, much of the world has turned out to be more mysterious than we first imagined, Penrose has a more powerful objection. The theory is driven by mathematics, “which is not an objection by itself” he argues, “as most of what I do is driven by mathematics.” Rather he put forward that if it’s meant to be a theory about the world it should make predictions which can be tested. But it seems that it is mostly, if not entirely, about the mathematics.

Professor Brian Greene offers his take, that the question we face doesn’t really grip onto what scientists are doing. We can’t pronounce how science should move on from this or that question. Scientists should choose what they find exciting. We should let people work on whatever they want as long as it gets results that inspire further research. If the work is fruitful, and it leads to future developments means then it should be pursued. A powerful argument for pluralism and to let scientists do that for which they are trained. Brian ends with the powerful argument, “leave it to the marketplace of ideas where scientists vote with the most precious resource that they have: their time.”