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On theories

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What is a theory? What makes a good theory?
We also look at accuracy and precision, historic examples, Karl Popper's ideas of a theories, Occam's razor, the scientific model etc. for an extensive look into the concept of a theory and its place in any discipline.

Published in: Science, Technology, Spiritual
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On theories

  1. 1. ON THEORIES V . H . B E L V A D I @ vhbelvadi v h b e l v a d i . c o m p h y s i c s c a p s u l e . c o m what are they and how do they work? flickr.com/josefstuefer
  2. 2. Scope ! You will be able to answer ! What is a theory? What are accuracy and precision? What are the characteristics of a good theory? What are theories in philosophy and in physics What is the scientific method? flickr.com/ryanwick
  3. 3. Contents 1 Definition of a theory 2 Systems and phenomena 3 Levels of theorising 4 Accuracy and precision 5 Good theory as a machine 6 Karl Popper’s characteristics 7 Provable v. unfalsifiable 8 Theories of philosophy v. theories of physics 9 Five more characteristics of a theory 10 Assumptions 11 The scientific method 12 Lex Parsimoniae
  4. 4. A man may die, nations may rise and fall, but an idea lives on. ! JOHN F. KENNEDY flickr.com/andrewtarvin
  5. 5. Theories are ideas
  6. 6. A supposition or a system of ideas intended to explain something. Oxford Dictionary
  7. 7. &the something is generally a phenomenon the explanation must be independent of the something Something
  8. 8. Let us examine this 1. How does a door rotate? 2. It works like one-quarter of a revolving door. 3. It works based on a hinge. ————————————————————————— Depends on another door 1. Why does a coin have two sides?——————————————————— Not a phenomenon
  9. 9. What is a phenomenon? φαίνειν - to manifest (itself) ! An event that is observable, occurs over a period of time and is measurable in some units and may or may not require the use of instruments. In physics: [phai-no-me-non]
  10. 10. System or phenomenon? A system is a portion of the universe chosen for study, which responds to any number of varying conditions. An event inside a system is a phenomenon.
  11. 11. Example 1 A aquarium is a system. When an aquarium is kept on fire, its water boils. When water is drained out, plants and fish die. When fish swim, their fins move to and fro. Phenomena Example 2 A panchayat is a system. When somebody throws a stone, others react. If it does not function well, people protest. If it rains, the panchayat meet is cancelled. Phenomena All these are simply parts of a system reacting to some occurrence inside or from outside that system
  12. 12. THEORY Hypothesis Law UNPROVEN SPECULATIVE PROVEN RESULTS, NOT MECHANISMS PROOFS MECHANISMS Facts
  13. 13. Terms in brief Axiom — the starting point of a reasoning, cannot be proven e.g. a line can be drawn between any two points Postulate — similar to an axiom, often only slightly more accurate Theorem — a logical consequence of a set of axioms with proof Corollary — a trivial theorem with little consequence to the problem it is often very close in similarity to a previous axiom or theorem Hypothesis — a statement capable of being proven, not yet proved Law — a proven statement, often tested over time with certainty
  14. 14. Accuracy+precision or,degreeofbeingunquestionable Axiom Postulate H ypothesis Theory Law Scientific process of thought
  15. 15. What are accuracy and precision? Accuracy Precision = Experimental or observational result Expected or known correct result Accurate,preciseAccurate,imprecise Inaccurate,impreciseInaccurate,precise
  16. 16. A theory must be precise and make accurate predictions.
  17. 17. So, when people say,! “I have a theory…” they actually mean! they have a hypothesis
  18. 18. A theory is like a machine Image: Frédéric Bisson
  19. 19. Takes in known facts Provides explanations Makes predictions THEORY
  20. 20. The unknown In other words: A good theory The known Discovery A useless theory Also useless
  21. 21. Karl PopperKarl Popper’s CHARACTERISTICS OF A GOOD SCIENTIFIC THEORY
  22. 22. 1 Easy to verify
  23. 23. 2 Make predictions
  24. 24. 3Make prohibitions
  25. 25. 4Must be testable
  26. 26. 5Failed tests of falsification are supportive evidences
  27. 27. But let us not forget that Popper supported Empirical falsification
  28. 28. whereas most science is still based on Francis Bacon’s Inductivism
  29. 29. Stephen Hawking sums it up
  30. 30. A theory is a good theory if it satisfies two requirements
  31. 31. It must accurately describe a large class of observations by relying on few arbitrary elements
  32. 32. It must make definite predictions about the results of future observations
  33. 33. Provable?! or Unfalsifiable?
  34. 34. Provable Unfalsifiable
  35. 35. Provable Unfalsifiable = can be proved
  36. 36. Provable Unfalsifiable = can be proved = cannot be disproved
  37. 37. Example What is a flame?
  38. 38. Example What is a flame? Lighting into a flame can be a phenomenon
  39. 39. A flame is a! body that! gives out! light and is! too hot to! hold in! one’s hand Proposed! theory
  40. 40. Provable?
  41. 41. Provable? Yes. All flames are hot and glowing.
  42. 42. Unfalsifiable?
  43. 43. Unfalsifiable? No. The cold flame experiment.
  44. 44. Find experiment instructions at j.mp/1tK5L0S
  45. 45. A glowing! body of! ignited gas! that is! generated by! something! on fire. Alternate! theory
  46. 46. Provable?
  47. 47. Provable? Clearly.
  48. 48. Unfalsifiable?
  49. 49. Unfalsifiable? Yes. All known flames are generated by things on fire and all known flames are composed of gasses.
  50. 50. TYPES OF THEORIES Theories of philosophy Theories in physics
  51. 51. TYPES OF THEORIES Theories of philosophy Theories in physics used in all sciences/social sciences; stated in english etc. used in physics, in addition to theories of philosophy; stated in mathematics
  52. 52. Theories in physics e.g. (James Clerk) Maxwell’s theory of electromagnetism
  53. 53. How does it work? The mathematics Dx Dy Dz charge volume =
  54. 54. How does it work? Electric flux ! (amount of electric field vectors emanating from a point) Amount of Amount of charge per unit volume The English
  55. 55. } These equations give us a physical picture of LIGHT Physical meaning — Light is a wave that looks like this:
  56. 56. If it is a good theory, What does it explain? What does it predict?
  57. 57. What does it explain? What does it predict?
  58. 58. What does it explain? What does it predict? The use of magnetism to store computer memory * Remember! The theory is from the 1860s, so it was a prediction then: this form of computer memory was used until the 1980s.
  59. 59. Some more characteristics
  60. 60. Replication
  61. 61. Unity One technique applicable to a wide range of problems
  62. 62. Fecundity The ability to give rise to new ideas
  63. 63. Independence of auxiliary hypotheses arising for or as a result of a given theory
  64. 64. Iteration Improve accuracy to improve/retain validity
  65. 65. Iteration Improve accuracy to improve/retain validity e.g. The orbit of planet Mercury
  66. 66. 7%
  67. 67. Assumptions An assumption can be a theory only if it is meant to be applied only in cases when the assumption is true
  68. 68. The scientific method Ask a question Formulate a hypothesis Determine the predictions of the hypothesis Theory, law etc.if correct make corrections if wrong Test the hypothesis Compare results & hypothesis
  69. 69. Occam’s razorwhen multiple explanations seem to exist among competing hypotheses, the one with the fewest assumptions should be selected William of Ockham late 1200s - early 1300s Lex Parsimoniae ‘leks - par - see - ‘moan - e - yea
  70. 70. Thank you VHBELVADI.COM / ON-THEORIES @vhbelvadi

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