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

Explore the limitations of scientific reasoning, the role of prior information, and the objectivity of evidence through examples and discussions. Delve into topics such as inductive vs deductive reasoning, the scientific method, and the influence of bias.

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

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

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

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

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

  6. Seeing is believing?: Striped nanoparticles

  7. Seeing is believing?: Striped nanoparticles

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

  9. Do we really see intermolecular bonds?

  10. 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!

  11. 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!

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

  13. 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.

  14. 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?

  16. 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.

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

  18. Objective and unbiased?

  19. Millikan’s Manipulation?

  20. 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)

  21. “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…

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