F34PPP Lecture 2: Wrong, not even wrong, or good enough?

1. F34PPP Lecture 2: Wrong, not even wrong, or good enough? Philip Moriarty School of Physics & Astronomy philip.moriarty@nottingham.ac.uk www.nottingham.ac.uk/physics/research/nano

2. F34PPP in brief -- assessment • A short blog post (300 - 500 words) [Deadline: Oct. 20] 10% • An opinion piece (along the lines of a one-page Physics World article, 1000-1500 words) [Deadline: Nov. 17] 30% • A "feature article" (2000-2500 words, in the style of a broadsheet article) [Deadline: Jan 12] 60%

3. Suggested blog post topics • 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? • Should Google have sacked James Damore? • Is “many worlds”/multiverse theory science? • Can science be crowd-funded? • Is peer review working? • Should universities cut back on funding of PhD positions? • Is Richard Dawkins closed-minded?

4. Last time… • Science is more than just a driver of technological/economic growth • Seeing is believing? How objective is our evidence?

5. Preview: Bayes and prior information “Your brain is always making use of prior information to make sense of new information coming in.”

6. Seeing is believing?: Striped nanoparticles https://muircheart.wordpress.com/2014/02/03/philip-moriarty-peer-review-cyber-bullies/

7. Do we really see intermolecular bonds? Zhang et al., Science 342 611 (2013)

8. Today • Inductive vs deductive reasoning • Bacon and inductivism • Is science really “organised scepticism”? • The scientific method • Popper and falsification

9. Logic and reason “Logic is the study of reasoning abstracted from what that reasoning is about.” [Ladyman]  All dachshunds are good physicists. Daisy is a dachshund. Therefore Daisy is a good physicist. Both are valid arguments!

10. Logic and reason: Deduction All dachshunds are good physicists Edward is a good physicist Therefore Edward is a dachshund. All human beings are animals Daisy is an animal Therefore Daisy is a human being Invalid arguments!

11. Another valid but bad argument The Bible says that God exists. The Bible is the word of God and therefore true. Therefore God exists.

12. Invalid but not necessarily bad argument… Moriarty claims to be a physicist I have no reason to believe he is lying Therefore Moriarty is a physicist Both premises could be true but conclusion could be false – invalid argument.

13. Induction and Bacon • Induction: deductively invalid but persuasive argument. • Observation without bias or prejudice (!) • Instruments should eliminate the role of the “unreliable senses” • Induction (in sense Bacon used term) is generalisation from N cases to all cases…

15. Objective evidence? How do you know? Have you taken the measurements, analysed the raw data, compared theory with the experimental results, coded the simulations? Just a matter of faith?

17. Aristotle vs Bacon • Aristotle – first formal study of logic. • Aristotelian logic entirely revolves around deductive reasoning. • He has very little to say on inductive reasoning, i.e. arguing from “the particular to the universal” • Inductive reasoning is “reasoning in which the premises seek to supply strong evidence for (not absolute proof of) the truth of the conclusion. “ [Wikipedia] • No place for experimentation in Aristotle’s logic.

18. Novum organum scientiarum • “New”, as opposed to Aristotle’s old Organon • Organised scepticism • Aristotelian methods too biased – “anticipation of Nature”

19. Objective and unbiased?

20. Millikan’s Manipulation?

21. Millikan’s Manipulation? But Millikan’s notebooks show that 175 drops were measured, with many measurements rejected because they didn’t “meet expectations”…. “This is almost exactly right & the best one I ever had!!! [20 December 1911]Exactly right [3 February 1912]Publish this Beautiful one [24 February 1912]Publish this surely / Beautiful !! [15 Mar1912]Error high will not use [15 March 1912, #2]Perfect Publish [11 April 1912]Won't work [16 April 1912, #2]Too high by 1½% [16 April 1912, #3]1% lowToo high e by 1¼%” “Flirting with Fraud: Millikan, Mendel and the Fringes of Integrity” -- https://www1.umn.edu/ships/ethics/millikan.htm M. Niaz, J. Res. Sci. Teching 37 480 (2000)

22. “It’s a thing that scientists are ashamed of…” “It's interesting to look at the history of measurements of the charge of an electron, after Millikan. If you plot them as a function of time, you find that one is a little bit bigger than Millikan's, and the next one's a little bit bigger than that, and the next one's a little bit bigger than that, until finally they settle down to a number which is higher.” “Why didn't they discover the new number was higher right away? It's a thing that scientists are ashamed of--this history--because it's apparent that people did things like this: When they got a number that was too high above Millikan's, they thought something must be wrong--and they would look for and find a reason why something might be wrong. When they got a number close to Millikan's value they didn't look so hard. And so they eliminated the numbers that were too far off, and did other things like that. We've learned those tricks nowadays, and now we don't have that kind of a disease.” Hmmm…

25. Back to Bacon…

26. The Idols of the Mind Idols of the Tribe – seeing order/patterns where there are none (cf “patternicity”!); wishful thinking; jumping to conclusions. Idols of the Cave – personal/ideological preferences. Idols of the Marketplace – fallacies in reasoning due to jargon and language. (Nothing to do with markets in “free market” sense, but we’ll come back to that topic…) Idols of the Theatre – being wedded to a particular (philosophical) framework.

27. Bacon’s Inductivism - Observation followed by Induction. - Bacon argues that observation must be based on methods which minimise the influence of the four idols. - Generate set of observations. - Use these observations as basis of generalisations – scientific laws. (e.g. F=GmM/r2 , PV = nRT, Snell’s law etc..etc..) “Man, as the minister and interpreter of nature, is limited in act and understanding by his observation of the order of nature; neither his understanding nor his power extends further.”

28. Induction and Bacon • Induction: deductively invalid but persuasive argument. • Observation without bias or prejudice (!) • Instruments should eliminate the role of the “unreliable senses” • Induction (in sense Bacon used term) is generalisation from N cases to all cases…

29. Bacon’s Inductivism – Some problems • We don’t really do experiments with no preconceived ideas, do we? • Nor do we completely disregard expertise (Idol of the Theatre). Is science truly underpinned by a “belief in the ignorance of experts”? • ..and does Bacon’s inductivism actually work?

30. David Hume • An empiricist (along with Locke, Berkeley) • Argues that Bacon’s inductive reasoning is “not really reasoning at all, but rather merely a habit or a psychological tendency to form beliefs about what has not yet been observed on the basis of what has already been observed.” [Ladyman, p.40]

31. When the sun goes down… • …how do we know it will rise again tomorrow morning? • Logically possible that sun won’t rise tomorrow. • Justification for sun rising tomorrow (or ball falling to ground when dropped) is on basis of experience • But we assume that the future will be the same as the past • Justified by logic? No. Logically possible for future to be different from past.