1. Philosophy of science in a nutshell Kareem Khalifa Middlebury College Department of Philosophy

2. Overview I. How do we know anything? II. How do we know anything in the sciences? III. Science and truth

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

4. II. How do we know anything in science? How are scientific claims justified? How are scientific claims justified? Rough idea: A scientific claim is justified if it provides the best fit between theory and data. 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: 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 ” The “ theoretical virtues ” –Power/scope/consilience –Consistency –Accuracy –Simplicity –Fruitfulness –Continuity with existing theory (conservatism)

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

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

12. How do we know anything in the sciences? We are justified in believing a scientific claim p if and only if: We are justified in believing a scientific claim p if and only if: 1. p is part of the most consistent, simple, accurate, and fruitful theory T. 2. T yields the greatest predictive, retrodictive, explanatory, observational, and manipulative success, and 3. 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? 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. 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 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) 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 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) In the life & social sciences, the situation is reversed: more observable things (e.g. neurons, individuals) explain less observable things (e.g. beliefs, societies)