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# Explanation classroomversion

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• 1. PHIL 160 PHIL 160 &quot;Explanation&quot;
• 2. PHIL 160 Goals of science: predictions manipulations explanations What is required for a good explanation?
• 3. Prediction vs. Explanation PHIL 160 What will happen next? Why did it happen? Prediction: Explanation:
• 4. PHIL 160 Why did it have to happen? How is it possible for this to happen? Why did this happen rather than something else? Why did it happen?
• 5. Deductive-Nomological model PHIL 160
• An explanation is a deductive argument.
• Conclusion = fact to be explained.
• Premises include a “law of nature” (universal regularity).
(from “nomos”, Greek for “law”)
• 6. Why is this bird black? PHIL 160
• This bird is a raven.
• All ravens are black.
 This bird is black.
• 7. Deductive-Nomological model PHIL 160
• Reduce explanations from one theory to equivalent explanations in terms of another theory.
• Explanation shed light on what’s really happening.
• Often requires “bridge laws”.
at work in “ intertheoretic reduction”
• 8. PHIL 160
• 9. PHIL 160
• 10. Why does the pressure of this gas sample increase? PHIL 160
• The volume of the gas sample is decreased.
• 2. Boyle’s law: PV= k .
 The pressure of the gas sample increases.
• 11. Kinetic Theory of Gases: PHIL 160
• A gas is a collection of point particles:
• occupying negligible volume.
• in constant motion through entire container.
• undergoing elastic collisions with walls of container and other particles.
• 12. PHIL 160
• 13. “ Bridge Laws” PHIL 160 Volume = space through which point particles are moving Pressure = force from collisions with walls/area Temperature = measure of the kinetic energy of the particles.
• 14. PHIL 160
• 15. PHIL 160 Volume of the gas sample is decreased (less space for particles to move through). Why does the pressure of this gas sample increase?
• 16. Why does the pressure of this gas sample increase? PHIL 160 Same number of particles with same kinetic energy  more frequent collisions with walls.
• 17. PHIL 160 More frequent collisions with walls  higher force/area (i.e., higher pressure) Why does the pressure of this gas sample increase?
• 18. Does D-N model work for all explanations? PHIL 160
• Is every argument that fits the model a good explanation?
• Does every good explanation fit the model?
• 19. PHIL 160  Alex didn’t get pregnant. Why didn’t Alex get pregnant?
• Alex takes birth control pills daily according to the instructions.
• Taken according to instructions, birth control pills are 99.9% effective at preventing pregnancy.
• 20. PHIL 160
• 21. Why did the salt dissolve? PHIL 160
• I hexed the salt.
• I put the (hexed) salt in water.
• Hexed salt dissolves in water.
 The salt dissolved.
• 22. PHIL 160
• I put the salt in water.
• Salt dissolves in water.
 The salt dissolved. Hexing is not explanatorily relevant! Why did the salt dissolve?
• 23. Why did Nancy get lung cancer? PHIL 160
• Nancy has smoked 2 packs of cigarettes a day for 10 years.
• Smoking 2 packs of cigarettes a day for 10 years causes lung cancer.
 Nancy got lung cancer.
• 24. PHIL 160 Smoking 2 packs of cigarettes a day for 10 years causes lung cancer. Not for every smoker! Not a law of nature. Why did Nancy get lung cancer?
• 25. PHIL 160
• 26. Why did these camellias die? PHIL 160
• The camellias were planted in hot, rich soil.
• Hot soil damages camellia roots.
 These camellias died.
• 27. Why did these camellias thrive? PHIL 160
• The camellias were planted in hot, rich soil.
• Camellias grow well in rich soil.
 These camellias thrived.
• 28. Cartwright : We don’t need a law! PHIL 160 We don’t need to know a law of nature to explain the camellias dying or thriving. There might be no such law of nature! (Explanation is still good.)
• 29. PHIL 160
• 30. Why is the flagpole’s shadow 4 meters long? PHIL 160
• Flagpole is 3 m high.
• Sunlight strikes pole at angle  .