Philip Moriarty School of Physics & F34PPP Lecture 3: Vive la Revolution?

Suggested blog post topics [300 – 500 words, 10%] - Should scientists have to justify their research in terms of its socioeconomic impact? - Do social media have a role to play in the scientific process? - When should scientists “go public” with their results? - Are prizes like the Longitude Prize the future of research funding? - Can science be crowd-funded? - Is peer review working? - Should universities cut back on funding of PhD positions? - Is Richard Dawkins closed-minded?

Last time… Bacon’s inductivism Idols of the Mind & Millikan’s manipulation Hume and the sunrise problem “There’s nothing that’s scientifically proven”

Inductive arguments “The very expression “scientifically proven” is a contradiction in terms. There’s nothing that is scientifically proven. The core of science is the deep awareness that we have wrong ideas, we have prejudices. …we have a vision of reality that is effective, it’s good, it’s the best we have found so far. It’s the most credible we have found so far; it’s mostly correct.” Carlo Rovelli phyisicist-explains-why-science-not-about-certainty

Hume: We assume the uniformity of nature Can we prove this? A “non-uniform” universe is conceivable Case for uniformity rests on argument from induction No logical/rational justification for uniformity? The uniformity of nature

“Whether this is something that should worry us, or shake our faith in science, is a difficult question that you should ponder for yourself”

Popper and Falsification

Need an infinity of cases to definitively verify that a theory is correct – problem of induction..but one case can prove it wrong. “All swans are white”. Hypothesis. Only one example required to prove it false – falsifiability. One example? Popper and Falsification

Bacon/ induction Popper

But this is not how lots of science (including physics!) is done. We very often don’t start with a theory. X Popper and Falsification The most exciting phrase to hear in science, the one that heralds new discoveries, is not Eureka!, but rather, “hmm…that’s funny” Issac Asimov

More problems with Popper How do we know we’ve falsified a theory? Could our experimental measurement/observation be flawed?

Popper’s “nihilism about induction” [Ladyman, p. 87] would mean that jumping out of a top-floor window is equally rational to taking the stairs. More problems with Popper

…but much greater scope for creativity in Popper’s version of the scientific method (as compared to Bacon’s inductivism) Leaps of faith?

2011/05/04/scientific-process-rage/

Vive la revolution?

“…unquestionably the most influential work of the philosophy of science in the last 50 years ” [Okasha]

Science is…? - cumulative - context of discovery and context of justification entirely distinct - evaluations are value-free - sharp distinction between theory and experiment - scientific terms have fixed and precise meanings

Science is…? …in a word, objective

Kuhn kuhn-structure-scientific-revolutions - A physicist by training, not a philosopher. PhD at Harvard. - Taught a “science for the humanities” course. - Came to realise that “context of discovery” and “context of justification” aren’t distinct. - Scientists work within a particular intellectual framework

Scientists are people too…

Normal science vs paradigm shifts concepts-startups-idea/ - “Normal science” operates within a particular paradigm - - Much more than just the prevailing theory – defines working methods of those scientists in the field. - Conservative

Normal science vs paradigm shifts - In “normal science”, if the experiment doesn’t work, the scientist assumes she has done something wrong. - Her results don’t agree with the paradigm – therefore she’s wrong. - Kuhn dismissive of Popper’s falsification thesis

From the introduction to the 50 th anniversary edition: "Normal science does not aim at novelty but at clearing up the status quo. It tends to discover what it expects to discover.” Ian Hacking Normal science vs paradigm shifts

Paradigm shifts - …but anomalies build up. - - Trigger “crisis of confidence” - - Revolution. - - Paradigm shift. - Major shift – “step change” in science, rather than incremental progress (Perhaps most contentious of all) -- values and beliefs of scientists key to acceptance of new paradigm

Paradigm shifts

Scientists driven by more than just rational consideration of the data and evidence. Peer pressure and “faith” important according to Kuhn..”.. crisis alone is not enough. There must also be a basis, though it need be neither rational nor ultimately correct, for faith in the particular candidate chosen. Something must make at least a few scientists feel that the new proposal is on the right track, and sometimes it is only personal and inarticulate aesthetic considerations that can do that.... ”

Seeing is believing?

Incommensurability “The normal-scientific tradition that emerges from a scientific revolution is not only incompatible but often actually incommensurable with that which has gone before” But in QM we have the correspondence principle. Similarly, we make sure that relativistic equations reduce to appropriate classical limit.