Understanding Science 12. The Galileo Gambit © Colin Frayn, 2015 www.frayn.net

Introduction The Galileo Gambit “They rejected Galileo, just like you’re rejecting me, but then it turned out he was right!” Implication: The pseudoscientist is also right Galileo Galilei (1564 - 1642) Argued in favour of Heliocentrism The Sun is at the centre of the Solar System The Copernican Model Galileo supported his beliefs with evidence Galileo was largely opposed for religious reasons © Colin Frayn, 2015 www.frayn.net

History Copernican theory Darwinian Evolution (1858-9) Was already accepted by several others Galileo also backed it up with evidence It was heavily opposed, even by other astronomers … but difficult to disentangle the influence of the Church Darwinian Evolution (1858-9) The original papers weren’t met with much of a response Opposed largely for religious reasons Also widely accepted among scientific circles Relativity (1905) Einstein backed up his theories with mathematics Very rapidly accepted Has since been backed up with evidence © Colin Frayn, 2015 www.frayn.net

Counter Examples There are lots of examples of really big discoveries that were readily accepted The existence of galaxies (Hubble, 1924-5) Harlow Shapley opposed the idea but soon changed his mind Hubble proved it using observations of variable stars in Andromeda Cosmic Expansion (Hubble, 1929) Initially opposed by some, but soon became widely accepted Hubble measured distance and recession speed of various galaxies Dark Matter (Various, 1930s; Rubin, 1970s) Not directly visible, but identified by its effects Stars in the outer parts of galaxies move far too quickly © Colin Frayn, 2015 www.frayn.net

Extraordinary Claims Not every extraordinary claim is false “No evidence” does not mean “not true” …but “evidence against” is different! Extraordinary = low Bayesian Prior Requires exceptionally high support What about impact? Consider both? Expectation Probability * Result P (H | E) = P (E | H) * P (H) P (E) Posterior Support Prior © Colin Frayn, 2015 www.frayn.net

Closed Mindedness Science deals in probabilities Closing off some lines of investigation is a good thing Especially if the chance of it being true is zeroid Science doesn’t say “never”! Hypotheses can be closed off or re-opened Closed minds, like doors, can be opened with the right key In this case, evidence © Colin Frayn, 2015 www.frayn.net

Advice How to get a Nobel prize If you’re a scientist : Get high quality evidence If you’re a pseudoscientist : Maybe write a book? Science is resistant to change for good reason Barrier against falsehoods Like an immune system Peer review, evidence gathering Replication A tower should be built on a strong foundation © Colin Frayn, 2015 www.frayn.net

Summary Galileo Gambit is a false analogy Revolutionary ideas do get accepted They just need to provide evidence! “All great ideas are initially rejected” does not imply “All rejected ideas are great” Rely on filtering based on Bayesian priors Iteratively investigate the most plausible / highest impact © Colin Frayn, 2015 www.frayn.net