Philosophy of science in a nutshell

1. Philosophy of sciencein a nutshell Kareem Khalifa Middlebury College Department of Philosophy

2. Overview • How do we know anything? • How do we know anything in the sciences? • Science and truth

3. I. How do we know anything? • Rough philosophical idea: Knowledge is justified true belief • How do you know? = What is your justification?

4. II. How do we know anything in science? • How are scientific claims justified? • Rough idea: A scientific claim is justified if it provides the best fit between theory and data.

5. How do theories fit with data? • A theory fits with data if: • The theory predicts the data • The theory retrodicts the data • The theory explains the data • The theory facilitates observation of the data • The theory facilitates control of the data

6. Bubble Chamber

7. Bubble Chamber Interpreted

8. fMRI

9. What makes one fit better than another? • The “theoretical virtues” • Power/scope/consilience • Consistency • Accuracy • Simplicity • Fruitfulness • Continuity with existing theory (conservatism)

10. Mrs. Smith was angry with Mr. Smith about his many mistresses. The butler murdered Mr. Smith Mrs. Smith murdered Mr. Smith. Mrs. Smith owned the gun that killed Mr. Smith. Mr. Smith’s blood was found on Mrs. Smith’s clothes. Toy Example Mr. Smith is dead.

11. The butler murdered Mr. Smith Mrs. Smith murdered Mr. Smith. Mrs. Smith owned the gun that killed Mr. Smith. Mr. Smith’s blood was found on Mrs. Smith’s clothes. The virtue of simplicity The butler planted blood on Mrs. Smith’s clothes The butler stole Mrs. Smith’s gun. Mr. Smith is dead.

12. How do we know anything in the sciences? • We are justified in believing a scientific claim p if and only if: • p is part of the most consistent, simple, accurate, and fruitful theory T. • T yields the greatest predictive, retrodictive, explanatory, observational, and manipulative success, and • T is continuous with existing theories also exhibiting these virtues.

13. Science and truth • Why is having good justification for a scientific claim a good reason for that claim to be true?

14. Three views on the truth of science • Realism: If good justification doesn’t entail truth, the success of science would be a miracle. • Empiricism: Only claims about observable entities can be true; claims about theoretical unobservable entities can be useful but false at no loss • Social constructivism: No scientific claims need to be true; scientific success is culturally relative (not unlike artistic success)

15. Realism and reduction • In physics & chemistry, less observable things (e.g. electrons) explain more observable things (e.g. voltmeter readings). • In the life & social sciences, the situation is reversed: more observable things (e.g. neurons, individuals) explain less observable things (e.g. beliefs, societies)