Controversy in High Energy Physics: ‘Post-empirical’ and determining future directions

Sophie Ritson 11.6.2018 The String Wars

“science” (Duff, 2013, p. 185) “speculative metaphysics” (Richter, 2006, pp. 8-9) “” (Krauss, 2005) “beautiful” (Schwarz, 1996, p. 698) “ugly” (Woit, 2006d, p. 265) “a final theory” (Weinberg, 1993, p. 212) “catastrophic failure” (Smolin, 2006b, p. 170). the debates have “raised deep questions about the very nature of physics as a discipline” (Galison, 1995b, p. 403). The String Wars • 1986 ‘Desperately Seeking Superstrings’ published in Physics Today Ginsparg and Glashow • 1999 The Elegant Universe written by Brian Greene • 2003/4 The Anthropic landscape • 2004 ‘Not Even Wrong’ the blog is launched by String Theory Critic Peter Woit • November 8 2005 Laurence Krauss writes an essay in the New York Times titled: Science and Religion Share Fascination in Things Unseen’ • 2006 Two books critical of string theory are published by Lee Smolin and Peter Woit • 2012 Dawid publishes String Theory and the • 2014 Editorial in Nature titled ‘Scientific Method: Defend the integrity of physics’by Ellis and Silk • 2014 ‘Why Trust a Theory Conference’ in Munich

A post empirical era?

• From the philosophical literature • on the basis of a lack of empiricism in string theory • the string theory debates are held up as evidence of emergent conceptualisation of science

This has led several historians and philosophers of science to ask if the widespread belief in string theory constitutes a new post empirical era for science The Demarcation Problem (according to Popper) “…since the autumn 1919 when I first begin to grapple with the problem, “When should a theory be ranked as scientific?" or "Is there a criterion for the scientific character or status of a theory?” The problem which troubled me at the time was neither, "When is a theory true?" nor "When is a theory acceptable?" my problem was different. I wished to distinguish between science and pseudo-science; knowing very well that science often errs, and that pseudoscience may happen to stumble on the truth” (Popper, 1962) “the criterion of the scientific status of a theory is its falsifiability” 60 years of philosophy of science

Falsificationism • Initial appeal: showed the rigour of scientists • Problems: failed logically, descriptively, normatively Lakatos: progressive research programmes predict novel facts which are confirmed by experiment • Initial appeal: matched well with historical episodes of widely considered successful science • Problems: only helpful retrospectively Kuhn: science is the current paradigm • Initial appeal: matched well with historical episodes of widely considered successful science (Copernican ‘revolution’) • Problems: many, but a big one was is this paradigm thing anyway? Laudan: embarked on a ambitious project to study the history of science to determine demarcation criteria The Demarcation Problem is a Pseudo- problem (according to Laudan)

“it seems pretty clear that philosophy has largely failed to deliver the relevant goods. Whatever the specific strengths and deficiencies of the numerous well-known efforts at demarcation, it is probably fair to say that there is no demarcation line between science and non-science, or between science and pseudoscience, which would win assent from a majority of philosophers or anyone else. Nor is there one which should win acceptance from philosophers or anyone else” Laudan (1983) ‘The demise of the demarcation problem’ in Physics, Philosophy and Psychoanalysis p. 111-112

“we aught to drop terms like ‘pseudo-science’ and ‘unscientific’ from our vocabulary; they are just hollow phrases which do only emotive work for us” Laudan (1983, p. 125) • Old view: there is one science • Based on consensus of methods, theories, approaches, etc. • “The Scientific Method” • Basic set of theories • All scientists speak the same language • New approach: enormous diversity in science • Beliefs, approaches, experiments, etc. • Consensus has to be achieved Boundary work

• Demarcation occurs in practical settings all the time • Gieyrn argues that demarcation occurs as part of efforts by scientists to distinguish their work “‘science’ is no single thing: it’s boundaries are drawn and redrawn in flexible, historically changing and sometimes ambiguous ways” (Gieryn, 1983, 781) • Boundary work is attributing selected characteristics to the institution of science More on Boundary Work

Gieryn (1999) Cultural Boundaries of Science: Credibility on the line • Defining epistemic authority as “the legitimate power to define, describe, and explain bounded domains of reality” • the label of science carries an “epistemic seal of approval” • the “contours of science are shaped by the local contingencies of the moment: the adversaries then and there, the stakes, the geographically challenged audiences ” • Scientists are “neither omniscient nor deceitful” “In this contest, each side draws a different map to create “science” as a distinctive ontological preserve over which they have legitimate claim to authoritative representation.” “mathematics is to science what masturbation is to sex” (Murray Gell-Mann) Is string theory really science?

“unless it allows an approximation scheme for “Faced with difficulties in applying fundamental yielding useful and testable physical theories to the observed Universe, some information, might be the sort of thing that researchers called for a change in how Wolfgang Pauli would have said is “not even theoretical physics is done. They began to argue — explicitly — that if a theory is sufficiently wrong”” (Ginsparg & Glashow, 1986, p. 39) elegant and explanatory, it need not be tested “more appropriate to departments of experimentally, breaking with centuries of mathematics or even to schools of divinity than philosophical tradition of defining scientific knowledge as empirical. We disagree. As the to physics departments” (Glashow, 1995). philosopher of science argued: a “no realistic possibility for a definitive theory must be falsifiable to be scientific. Chief confirmation or falsification of a unique among the 'elegance will suffice' advocates are prediction from it by a currently doable some string theorists … experiment” (Smolin, 2006) post-empirical science is an oxymoron ”(Ellis & “much of what currently passes as the most Silk, 2014) advanced theory looks to be more theological speculation” (Richter, 2006) String theory is a testable in principle. Just not yet in practice “The history of science is filled with “supersymmetry (which historically was ideas that when first presented seemed discovered at least in part because of its completely untestable … ideas that we role in string theory) is a genuine now accept fully but that, at their prediction of string theory” (Witten, inception, seemed more like musings of 1998) science fiction than aspects of science “String theory is full of qualitative fact” (Greene, 1999) predictions, such as the production of “gravitational waves (1916), the black holes in the LHC [Large Hadron cosmological constant (1917) … [and] Collider] or cosmic strings in the sky, the Higgs boson (1964)” serve as and this level of prediction is perfectly instructive examples of theoretical acceptable in almost every other field of predictions that were untestable when science .. Only in experimental particle they were first announced (Duff, 2013) physics is it the case that a theory can be thrown out if the 10th decimal place of a prediction doesn’t agree with experiment” (Gross, 2007) Retro-dictions and counterfactual histories

“these theories have (or this one theory has) the remarkable property of predicting gravity” (Witten, 1996)

“had history followed a different course – and had physicists come upon string theory some hundred years earlier – we can imagine that these symmetry principles would have been discovered by studying its properties” (Greene, 1999) String theory makes progress by solving problems “String and M-theory continue to make remarkable theoretical progress, for example by providing the first microscopic derivation of the black hole entropy formula first proposed by Hawking in the mid 1970s. Solving long outstanding theoretical problems such a this indicates that we are on the right track.” (Duff, 2013) Self-immunisation strategies and ad hoc manoeuvres “while supersymmetry is not precisely unfalsifiable, it is difficult to falsify, as many negative results can be-and have been- dealt with by changing the parameters of the theory” (Smolin, 2007)

“[t]he world doesn’t have eleven dimensions, so it rolls up seven. Why not six, why not four? It’s a hell of a theory isn’t it? One can’t even check the number of dimensions.” (Feynman, 1988) Against Falsificationism

“Good scientific methodology is not an abstract set of rules dictated by philosophers. It is conditioned by, and determined by, the science itself and the scientists who create the science. What may have constituted scientific proof for a particle physicist of the 1960’s – namely the detection of an isolated particle – is inappropriate for a modern quark physicist who can never hope to remove and isolate a quark. Let’s not pull the cart before the horse. Science is the horse which pulls philosophy … Falsification in my opinion is a red herring, but confirmation is another story. By confirmation I mean direct positive evidence for a hypothesis rather than the absence of negative evidence” (Susskind, 2005) Against Falsificationism

“String theory and other approaches to quantum gravity involve phenomena that are likely to manifest themselves only at energies enormously higher than anything we have access to here on Earth. Some scientists, leaning on Popper, have suggested that these theories are non-scientific because they are not falsifiable. The truth is the opposite. Whether or not we can observe them directly, the entities involved in these theories are either real or they are not. Refusing to contemplate their possible existence on the grounds of some a priori principle, even though they might play a crucial role in how the world works, is as non-scientific as it gets.” (Carroll, 2014) The landscape of string theory: physics or metaphysics? “Fundamentally, the multiverse explanation relies on string theory, which is as yet unverified, and on speculative mechanisms for realizing different physics in different sister universes. It is not, in our opinion, robust, let alone testable.

To state that a theory is so good that its existence supplants the need for data and testing in our opinion risks misleading students and the public as to how science should be done and could open the door for pseudoscientists to claim that their ideas meet similar requirements.

The imprimatur of science should be awarded only to a theory that is testable. Only then can we defend science from attack.” (Ellis & Silk, 2014) A post empirical era? Unique example amongst studied episodes of boundary work A post empirical era? - problems with this view

• Misunderstands the debates • ‘Widespread belief’ is probably a stretch • Controversial • Not just one debate • Ambiguity in determining if string theory in ‘on the right track’ • Attempts to set out their views on science, which they hope may shape the direction of physics

• Debates concern notions of • a view of what science is and how science works • what will be science • how it should be done • and from what notions of science progress is most likely to occur Open questions

How to consider the current state of high energy physics? • Lack of any new (thus far) results from the LHC

How should and can progress occur? • How can ‘non-discovery’ guide progress? And suggest future directions? • No BSM model confirmations, or SM deviations • How to address the problems with the standard model?