Unit 1. What can we know?


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Unit 1. What can we know? [Philosophy of Science]

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Unit 1. What can we know?

  1. 1. Unit 1<br />What can we know?<br />
  2. 2. What is science?<br />
  3. 3. Write down what you think science is<br />Name five examples<br />
  4. 4. The traditional view of science <br />Science comes from the Latin word scientia which means knowledge. <br />Science gives us knowledge of reality. <br />This knowledge is objective, generalisable, controllable<br />
  5. 5. Philosophy comes from the Greek φιλοσοφία (philosophia) which means love of wisdom.<br />Philosophy studies general and fundamental problems.<br />The philosophy of science can help us reflect on the nature of science. <br />
  6. 6.
  7. 7. The definition of science effects real life<br />
  8. 8. Rationalism and Empiricism<br />
  9. 9.
  10. 10. Deductive reasoning goes from all (a general rule) to one (a specific case).<br />Inductive reasoning goes from one (a bunch of single data) to all (a general conclusion).<br />A priori= before experience<br />A posteriori = after experience<br />
  11. 11. Rationalism and deduction<br />
  12. 12. Descartes (1596-1650):<br /> Doubt your senses<br />
  13. 13. What if there is no God, but just an evil demon tricking us<br />Then I might be sleeping, dreaming I am awake<br />
  14. 14. But the demon can never trick me into the idea I don’t exist. <br />Cogito ergo sum?<br />
  15. 15.
  16. 16.
  17. 17.
  18. 18. Deduction<br />Deduction is logical reasoning. <br />Deductive knowledge is a priori knowledge that is known independent of experience. <br />Deductive arguments are purely logical. <br />
  19. 19. a deductive inference<br />Standard example of a deductive inference:<br />Premises All men are mortal.<br />Socrates is a man.<br />Conclusion Socrates is mortal.<br />
  20. 20. Empiricism and induction<br />
  21. 21. Induction<br />Inductive knowledge is knowledge based on sensory experience. <br />Inductive knowledge is a posteriori knowledge, knowledge that is gained by experience (that is, it is empirical, or arrived at afterward).<br />
  22. 22. David Hume’s (1711-1776) fork<br />
  23. 23. Analytic: statements about ideas<br />Synthetic: statements about the world<br />
  24. 24. Example of an analytical sentence:<br />All bachelors are unmarried.<br />Example of a synthetic sentence:<br />All bachelors are bald.<br />
  25. 25. Hume’s problem was that it is almost impossible to go from synthetic to analytic statements. <br />
  26. 26. Because we can never relate the analytic sentences to the real world it is meaningless, they only speaks about them self. <br />Consider the example of the bachelor: it is a tautological sentence, it is always valid regardless of your data.<br />
  27. 27. A thousand white swans<br />Take the example of a white swan. Can we be certain that if we see a thousand white swans, that all swans are white?<br />No. <br />Even if we have a thousand observations like: this swan is white, we can never relate this to the rule all swans are white. <br />Only if we would see every swan in the universe – now and in the future- which is impossible.<br />
  28. 28. The fact that the sun has risen everyday up until now may not prove that it will rise tomorrow, but surely it gives us a very good reason to think it will? <br />