PHIL 160 PHIL 160 "Kuhn: Crisis & Revolution"
PHIL 160 NORMAL SCIENCE CRISIS REVOLUTION
PHIL 160 LEARNING OBJECTIVES: PHIL 160 •  Crisis (questioning the paradigm) •  Factors for choosing between  paradigms •  ...
PHIL 160 PARADIGM
PARADIGM •  Ideas about what kind of stuff •  Ideas about what kinds of behaviors PHIL 160
PARADIGM •  Methodology •  Interesting questions (puzzles) •  What counts as a good explanation •  Ideas about what kind o...
Puzzle-solving PHIL 160 NORMAL SCIENCE Shared PARADIGM
PHIL 160 Puzzle-solving Solved puzzles NORMAL SCIENCE Shared PARADIGM
Resistant Puzzles PHIL 160 Puzzle-solving Solved puzzles NORMAL SCIENCE Shared PARADIGM
If paradigm is right, these puzzles have solutions … but we can’t find them! Resistant Puzzles PHIL 160 Puzzle-solving Sol...
PHIL 160 NORMAL SCIENCE Shared PARADIGM Puzzle-solving Solved puzzles CRISIS ANOMALIES Resistant Puzzles
PHIL 160 PHIL 160 PHIL 160
PHIL 160 CRISIS
PHIL 160 CRISIS •  Proliferation of different  adjustments to the paradigm •  Erosion of agreement about fundamentals •  S...
PHIL 160
NORMAL SCIENCE CRISIS PHIL 160 shared assumptions different assumptions How to keep doing science?
PHIL 160 How well does each paradigm do with: <ul><li>Resistant puzzles? </li></ul><ul><li>Solved puzzles? </li></ul><ul><...
PHIL 160 <ul><li>Fit with paradigms in nearby fields? </li></ul>How well does each paradigm: Paradigm Comparison Shopping
PHIL 160 How well does each paradigm: <ul><li>Fit with your aesthetic sense (or with the way the world “feels” to you)? </...
<ul><li>Fit with your observations of the phenomena? </li></ul>PHIL 160 Paradigm Comparison Shopping How well does each pa...
<ul><li>Competing paradigms of planetary motion (Ptolemaic vs. Copernican) </li></ul>PHIL 160 Paradigm Comparison Shopping...
PHIL 160 Phenomena to be explained: 1.  Sun’s yearly movement against the background of the zodiac constellations (one ful...
PHIL 160 Two-sphere model of the universe:
PHIL 160 Two-sphere model of the universe: whole celestial sphere rotates once per day.
PHIL 160 Two-sphere model of the universe: whole celestial sphere rotates once per day. Sun travels along ecliptic approx ...
PHIL 160 Phenomena to be explained: 2.  Planets’ movement against the background of fixed stars. (Different rates for diff...
PHIL 160 Basic model for planetary motion: Earth at center. (“Geocentric” system) Sun and planets orbiting Earth on circul...
PHIL 160
PHIL 160 Phenomena to be explained: <ul><li>Mars, Jupiter, and Saturn have a “retrograde” (backwards) motion at various po...
PHIL 160 Phenomena to be explained: <ul><li>Mercury and Venus always stay within a certain maximum angular distance of the...
PHIL 160 Refinements to the model:
PHIL 160 Refinements to the model: Planets travel on little circles (epicycles) …
PHIL 160 Refinements to the model: Planets travel on little circles (epicycles) … …  which go around Earth on deferent (bi...
PHIL 160 Refinements to the model: Planets travel on little circles (epicycles) … …  which go around Earth on deferent (bi...
PHIL 160 SUN C MARS EARTH
PHIL 160 How do epicycles help with inner planets? Inner planets stay within a certain maximum angular distance of the Sun...
PHIL 160 SUN EARTH VENUS C
PHIL 160 A pretty good model (with some anomalies) Explains retrograde motion of outer planets. Explains maximum angular d...
PHIL 160 Make more modifications to fix anomalies? Shift Earth slightly from center of orbit.  Eccentric model
PHIL 160 Make more modifications to fix anomalies? Equant model Shift planet’s center of motion from center of orbit P swe...
PHIL 160 EARTH MARS C
PHIL 160 Too much modification? What was a clean system is now pretty complicated. Hard to use to make predictions, calcul...
PHIL 160
PHIL 160
PHIL 160
PHIL 160 Copernican (heliocentric) model: Put Sun at center of the system Earth and planets on circular orbits around the ...
PHIL 160 SUN C EARTH MARS
PHIL 160 Copernican model on retrograde:
PHIL 160 SUN EARTH VENUS
PHIL 160 Copernican (heliocentric) model: Copernicus explicitly argued that his system was  geometrically equivalent  to P...
PHIL 160 SUN C MARS EARTH
PHIL 160 SUN C EARTH MARS
PHIL 160 SUN EARTH VENUS C
PHIL 160 SUN EARTH VENUS
PHIL 160 Beyond predictions of planetary motion: How do the Ptolemaic and Copernican paradigms fit with paradigms in nearb...
PHIL 160
PHIL 160
PHIL 160
PHIL 160
PHIL 160 Beyond predictions of planetary motion: Christian theology: Earth at center of creation;  Earth as unique (not ju...
PHIL 160
PHIL 160 Fit with observations:  TIE (Make identical predictions) Ptolemy vs. Copernicus
Ptolemy vs. Copernicus PHIL 160 Solving/dissolving unsolved puzzles: COPERNICUS (Don’t have to explain alignment of epicyc...
PHIL 160 <ul><li>Fit with other theories: </li></ul><ul><ul><li>Physics:  PTOLEMY </li></ul></ul><ul><ul><li>Theology: PTO...
PHIL 160 Aesthetics (simplicity): COPERNICUS (All those epicycles make things confusing) Ptolemy vs. Copernicus
PHIL 160 Split decision: who wins? (Which factors are most important for the choice?) Ptolemy vs. Copernicus
PHIL 160 Relative importance of : <ul><li>Unsolved puzzles? </li></ul><ul><li>Solved puzzles? </li></ul><ul><li>Fit with d...
PHIL 160
PHIL 160
PHIL 160 What we observe is  paradigm dependent ! (So, how is a paradigm shift progress?) NEXT CLASS
PHIL 160 LEARNING OBJECTIVES: PHIL 160 •  Crisis (questioning the paradigm) •  Factors for choosing between  paradigms •  ...
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P160 Kuhn classroom Lecture 2

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Phil 160 lecture, "Kuhn: Crisis and Revolution," San Jose State University.

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P160 Kuhn classroom Lecture 2

  1. 1. PHIL 160 PHIL 160 &quot;Kuhn: Crisis & Revolution&quot;
  2. 2. PHIL 160 NORMAL SCIENCE CRISIS REVOLUTION
  3. 3. PHIL 160 LEARNING OBJECTIVES: PHIL 160 • Crisis (questioning the paradigm) • Factors for choosing between paradigms • Subjectivity of paradigm shift
  4. 4. PHIL 160 PARADIGM
  5. 5. PARADIGM • Ideas about what kind of stuff • Ideas about what kinds of behaviors PHIL 160
  6. 6. PARADIGM • Methodology • Interesting questions (puzzles) • What counts as a good explanation • Ideas about what kind of stuff • Ideas about what kinds of behaviors PHIL 160
  7. 7. Puzzle-solving PHIL 160 NORMAL SCIENCE Shared PARADIGM
  8. 8. PHIL 160 Puzzle-solving Solved puzzles NORMAL SCIENCE Shared PARADIGM
  9. 9. Resistant Puzzles PHIL 160 Puzzle-solving Solved puzzles NORMAL SCIENCE Shared PARADIGM
  10. 10. If paradigm is right, these puzzles have solutions … but we can’t find them! Resistant Puzzles PHIL 160 Puzzle-solving Solved puzzles ANOMALIES NORMAL SCIENCE Shared PARADIGM
  11. 11. PHIL 160 NORMAL SCIENCE Shared PARADIGM Puzzle-solving Solved puzzles CRISIS ANOMALIES Resistant Puzzles
  12. 12. PHIL 160 PHIL 160 PHIL 160
  13. 13. PHIL 160 CRISIS
  14. 14. PHIL 160 CRISIS • Proliferation of different adjustments to the paradigm • Erosion of agreement about fundamentals • Suspicion that paradigm is fatally flawed
  15. 15. PHIL 160
  16. 16. NORMAL SCIENCE CRISIS PHIL 160 shared assumptions different assumptions How to keep doing science?
  17. 17. PHIL 160 How well does each paradigm do with: <ul><li>Resistant puzzles? </li></ul><ul><li>Solved puzzles? </li></ul><ul><li>New puzzles? </li></ul>Paradigm Comparison Shopping
  18. 18. PHIL 160 <ul><li>Fit with paradigms in nearby fields? </li></ul>How well does each paradigm: Paradigm Comparison Shopping
  19. 19. PHIL 160 How well does each paradigm: <ul><li>Fit with your aesthetic sense (or with the way the world “feels” to you)? </li></ul>Paradigm Comparison Shopping
  20. 20. <ul><li>Fit with your observations of the phenomena? </li></ul>PHIL 160 Paradigm Comparison Shopping How well does each paradigm:
  21. 21. <ul><li>Competing paradigms of planetary motion (Ptolemaic vs. Copernican) </li></ul>PHIL 160 Paradigm Comparison Shopping Another historical example:
  22. 22. PHIL 160 Phenomena to be explained: 1. Sun’s yearly movement against the background of the zodiac constellations (one full circuit/year). (Includes positions of sunrises and sunsets, positions of noontime sun on solstices and equinoces.) Utterly commonsense assumption: the Earth isn’t moving.
  23. 23. PHIL 160 Two-sphere model of the universe:
  24. 24. PHIL 160 Two-sphere model of the universe: whole celestial sphere rotates once per day.
  25. 25. PHIL 160 Two-sphere model of the universe: whole celestial sphere rotates once per day. Sun travels along ecliptic approx 1 o per day (full circuit once per year)
  26. 26. PHIL 160 Phenomena to be explained: 2. Planets’ movement against the background of fixed stars. (Different rates for different planets.) Very convenient fact: Each of the planets travels roughly along the belt of zodiac constellations (the ecliptic). Can use 2-dimensional model (the plane the ecliptic cuts through the celestial sphere)
  27. 27. PHIL 160 Basic model for planetary motion: Earth at center. (“Geocentric” system) Sun and planets orbiting Earth on circular orbits of various sizes.
  28. 28. PHIL 160
  29. 29. PHIL 160 Phenomena to be explained: <ul><li>Mars, Jupiter, and Saturn have a “retrograde” (backwards) motion at various points in their movement against the background of the zodiac constellations. </li></ul>
  30. 30. PHIL 160 Phenomena to be explained: <ul><li>Mercury and Venus always stay within a certain maximum angular distance of the Sun. </li></ul><ul><li>These behaviors of “inner planets” (Mercury and Venus) and “outer planets” (Mars, Jupiter, and Saturn) require modifications to plain circular orbits around Earth. </li></ul>
  31. 31. PHIL 160 Refinements to the model:
  32. 32. PHIL 160 Refinements to the model: Planets travel on little circles (epicycles) …
  33. 33. PHIL 160 Refinements to the model: Planets travel on little circles (epicycles) … … which go around Earth on deferent (big) circles)
  34. 34. PHIL 160 Refinements to the model: Planets travel on little circles (epicycles) … … which go around Earth on deferent (big) circles) Retrograde motion observed when planet is on inside of its epicycle.
  35. 35. PHIL 160 SUN C MARS EARTH
  36. 36. PHIL 160 How do epicycles help with inner planets? Inner planets stay within a certain maximum angular distance of the Sun. Important feature of Ptolemy’s model: Center of a planet’s epicycle stays lined up with the Sun on its orbit of the Earth.
  37. 37. PHIL 160 SUN EARTH VENUS C
  38. 38. PHIL 160 A pretty good model (with some anomalies) Explains retrograde motion of outer planets. Explains maximum angular distance of inner planets from Sun. But: Some portions of planets’ orbits are faster, others are slower. Planetary orbits are not perfectly circular.
  39. 39. PHIL 160 Make more modifications to fix anomalies? Shift Earth slightly from center of orbit. Eccentric model
  40. 40. PHIL 160 Make more modifications to fix anomalies? Equant model Shift planet’s center of motion from center of orbit P sweeps out equal angles in equal times. (Slower on top of circle, faster on bottom)
  41. 41. PHIL 160 EARTH MARS C
  42. 42. PHIL 160 Too much modification? What was a clean system is now pretty complicated. Hard to use to make predictions, calculations. (No longer strictly geocentric.) Unsolved puzzles: No explanation for sizes of epicycles and deferent circles. No explanation for why epicycles of inner planets orbit Earth at same rate as Sun and stay lined up with Sun.
  43. 43. PHIL 160
  44. 44. PHIL 160
  45. 45. PHIL 160
  46. 46. PHIL 160 Copernican (heliocentric) model: Put Sun at center of the system Earth and planets on circular orbits around the sun. Drop the epicycles!
  47. 47. PHIL 160 SUN C EARTH MARS
  48. 48. PHIL 160 Copernican model on retrograde:
  49. 49. PHIL 160 SUN EARTH VENUS
  50. 50. PHIL 160 Copernican (heliocentric) model: Copernicus explicitly argued that his system was geometrically equivalent to Ptolemy’s. (Predict the same planetary motions from a less complicated model.)
  51. 51. PHIL 160 SUN C MARS EARTH
  52. 52. PHIL 160 SUN C EARTH MARS
  53. 53. PHIL 160 SUN EARTH VENUS C
  54. 54. PHIL 160 SUN EARTH VENUS
  55. 55. PHIL 160 Beyond predictions of planetary motion: How do the Ptolemaic and Copernican paradigms fit with paradigms in nearby fields? Aristotelian Physics (grounded in 4-element theory of matter): “ Everything goes to its natural place.” Heavy elements (like water and earth) go toward center of universe, light elements away from center.
  56. 56. PHIL 160
  57. 57. PHIL 160
  58. 58. PHIL 160
  59. 59. PHIL 160
  60. 60. PHIL 160 Beyond predictions of planetary motion: Christian theology: Earth at center of creation; Earth as unique (not just another planet).
  61. 61. PHIL 160
  62. 62. PHIL 160 Fit with observations: TIE (Make identical predictions) Ptolemy vs. Copernicus
  63. 63. Ptolemy vs. Copernicus PHIL 160 Solving/dissolving unsolved puzzles: COPERNICUS (Don’t have to explain alignment of epicycles if there are no epicycles)
  64. 64. PHIL 160 <ul><li>Fit with other theories: </li></ul><ul><ul><li>Physics: PTOLEMY </li></ul></ul><ul><ul><li>Theology: PTOLEMY </li></ul></ul>(No astronomer is an island) Ptolemy vs. Copernicus
  65. 65. PHIL 160 Aesthetics (simplicity): COPERNICUS (All those epicycles make things confusing) Ptolemy vs. Copernicus
  66. 66. PHIL 160 Split decision: who wins? (Which factors are most important for the choice?) Ptolemy vs. Copernicus
  67. 67. PHIL 160 Relative importance of : <ul><li>Unsolved puzzles? </li></ul><ul><li>Solved puzzles? </li></ul><ul><li>Fit with data? </li></ul><ul><li>Puzzle-solving power? </li></ul>Answers depend on which paradigm you’re in! Paradigm Comparison Shopping
  68. 68. PHIL 160
  69. 69. PHIL 160
  70. 70. PHIL 160 What we observe is paradigm dependent ! (So, how is a paradigm shift progress?) NEXT CLASS
  71. 71. PHIL 160 LEARNING OBJECTIVES: PHIL 160 • Crisis (questioning the paradigm) • Factors for choosing between paradigms • Subjectivity of paradigm shift PHIL 160 PHIL 160

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