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Theory Of Falsification And Its Evolution


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Theory Of Falsification And Its Evolution

  1. 1. Theory of Falsification and its evolution
  2. 2. Domain of this talk <ul><li>Epistemology: B ranch of philosophy concerned with the nature and scope of knowledge </li></ul><ul><li>Ontology : Study of conceptions of reality and the nature of being </li></ul><ul><li>Is science based on faith? </li></ul><ul><li>What is the scientific method? </li></ul><ul><li>How are new discoveries treated? </li></ul><ul><li>Is everything reducible to physics and mathematics? </li></ul><ul><li>Is everything reducible to a few rules? </li></ul>Philosophy of Science
  3. 3. The Middle Ages <ul><li>5th century -16th century </li></ul><ul><li>Medieval and Dark Ages </li></ul>Saint Augustine Islamic al- Andalus passed much of this on to Europe The replacement of Roman numerals with the decimal positional number system and the invention of algebra allowed more advanced mathematics . First Crusade 1095-1099 Second Crusade 1147–1149 116 years of war from 1337 – 1453 Between France & England Islamic Golden Age
  4. 4. Heliocentrism & Church <ul><li>Western Christian biblical references: </li></ul><ul><li>Psalm 93:1, Psalm 96:10, and 1 Chronicles 16:30 include text stating that &quot; the world is firmly established, it cannot be moved .&quot; </li></ul><ul><li>In the same tradition, Psalm 104:5 says, &quot; the LORD set the earth on its foundations; it can never be moved.“ </li></ul><ul><li>Further, Ecclesiastes 1:5 states that &quot; And the sun rises and sets and returns to its place, etc.&quot; [ 74] </li></ul>Galileo (1564 – 1642) Thomas Aikenhead (c. 1678 - 8 January 1697 ) was a Scottish student from Edinburgh , who was prosecuted and executed on a charge of blasphemy
  5. 5. Logical Induction <ul><li>Induction is dominant mode of inquiry </li></ul><ul><li>Truth observed through empirical study and experimentation </li></ul><ul><li>Rational and unbiased examination of nature </li></ul><ul><li>Observation </li></ul><ul><li>Repetition </li></ul><ul><li>Induction(1) </li></ul><ul><li>Hypothesis </li></ul><ul><li>Deduction or generalization </li></ul><ul><li>Consequence or prediction </li></ul><ul><li>Testing </li></ul><ul><li>Induction(2) </li></ul>Bacon (1561-1626)
  6. 6. Laws of motion &quot;Gravity explains the motions of the planets, but it cannot explain who set the planets in motion. God governs all things and knows all that is or can be done.&quot; [17] Newton may have rejected the church's doctrine of the Trinity. Newton refashioned the world governed by an interventionist God into a world crafted by a God that designs along rational and universal principles. [24] These principles were available for all people to discover, allowed people to pursue their own aims fruitfully in this life, not the next , and to perfect themselves with their own rational powers. [25] Sir Isaac Newton ( 1643  – 1727 )
  7. 7. Epistemology Knowledge is justified true belief The justification for the belief must be infallible. The Gettier problem <ul><li>Specific theories of knowledge acquisition: </li></ul><ul><li>Empiricism : all hypotheses and theories must be tested against observations of the natural world , rather than resting solely on a priori reasoning , intuition , or revelation . </li></ul><ul><li>Rationalism : knowledge is primarily acquired by intuition. Any view appealing to reason as a source of knowledge or justification </li></ul><ul><li>Constructivism : scientific knowledge is constructed by scientist and not discover from the world through strict scientific method </li></ul>
  8. 8. 18th Century Epistemologist Rationalism Descartes Spinoza Leibniz Empiricism Locke Berkeley Hume Wolff Kant It is our ideas which give form to reality, not reality which gives form to our ideas.
  9. 9. All A observed so far are B.   [i.e. All A are B] X is an A not yet observed.     [i.e. X is not an A] Therefore X is B.       [X is B.] What does it take to confirm a universal generalization? Logical Problem of Induction Deductive logic (drastically oversimplified): All A are B. X is an A. Therefore X is B. Inductive logic All copper we have tested conducts electricity. X is a piece of copper yet to be tested. Therefore X will conduct electricity.
  10. 10. Logical Positivism <ul><li>Vienna Circle included Rudolf Carnap, Otto Neurath, Viktor Kraft, Hans Hahn, and Herbert Feigl. </li></ul><ul><li>The principal objective of the members of the Circle was to unify the sciences, which carried with it, in their view, the need to eliminate metaphysics once and for all by showing that metaphysical propositions are meaningless. </li></ul>Tractatus Logico-Philosophicus Rudolf Carnap ( 1891 - 1970 ) Bertrand Russell ( 1872 – 1970 ) Ludwig Wittgenstein ( 1889 – 1951 )
  11. 11. Goodman’s Riddle: Grue and Bleen <ul><li>When there is more than one inductive conclusion that is consistent with our observations, which one should we chose? </li></ul><ul><li>Grue: Observed before or at t and green or observed after t and blue. </li></ul><ul><li>Let t be midnight, Decmber 31 2009. </li></ul><ul><li>Then all observed emeralds are grue / green. </li></ul><ul><li>Should we infer by simple induction that all emeralds are grue or green? </li></ul>Bleen : X is examined before the year 2000 and found to be blue, or X is not examined until after the year 2000 and found to be green Green : X is green if examined before the year 2000 and found to be grue, or X is not examined until after the year 2000 and found to be bleen. Henry Nelson Goodman ( 1906 - 1998 )
  12. 12. The Falsification Thesis Sir Karl Raimund Popper ( 1902  – 1994 ) <ul><li>Murderer of Freud and Marx Ideas </li></ul><ul><li>Problem with Darwinian Evolution </li></ul>He published his first book, Logik der Forschung ( The Logic of Scientific Discovery ), in 1934 . Here, he criticised psychologism , naturalism , inductionism , and logical positivism , and put forth his theory of potential falsifiability as the criterion demarcating science from non-science. <ul><li>Scientific theories are never truly verified. Moreover, to be always verified is not a virtue in a scientific theory </li></ul><ul><li>Verification and falsification are asymmetrical : </li></ul><ul><li>No accumulation of confirming instances is sufficient to verify a universal generalization. </li></ul><ul><li>But only one disconfirming instance suffices to refute a universal generalization. </li></ul><ul><li>Scientific theories are distinguished by the fact that they are capable of being refuted. They are falsifiable. </li></ul>you can never justify any scientific theory, but you can falsify it Charles Robert Darwin ( 1809 – 1882 ) Karl Heinrich Marx ( 1818 – 1883 ) Sigismund Freud ( 1856 – 1939 )
  13. 13. Einstein’s General Relativity: If it had failed its famous test of 1919, no one would have taken it seriously. But it passed the test, and Newton’s theory of gravitation was refuted. Albert Einstein (1879-1955) Light from a star passing near the Sun should be deflected. The evidence is the displacement of the star’s apparent position. Empirical Test of General Relativity
  14. 14. Falsification of Darwinian Evolution Richard Dawkins said that &quot;If there were a single hippo or rabbit in the Precambrian, that would completely blow evolution out of the water. None have ever been found. Human DNA should be more similar to great apes than other mammals. If this is not the case, then common descent is falsified. Popper said that natural selection &quot;is not a testable scientific theory but a metaphysical research program&quot;. However, Popper later said &quot;I have changed my mind about the testability and logical status of the theory of natural selection, and I am glad to have the opportunity to make a recantation.&quot; &quot;Darwin's own most important contribution to the theory of evolution, his theory of natural selection, is difficult to test.&quot; However, &quot;[t]here are some tests, even some experimental tests; and in some cases, such as the famous phenomenon known as 'industrial melanism', we can observe natural selection happening under our very eyes, as it were. Nevertheless, really severe tests of the theory of natural selection are hard to come by, much more so than tests of otherwise comparable theories in physics or chemistry.&quot; The model of cultural evolution known as memetics is as of yet unfalsifiable
  15. 15. Popperian Cosmology World 1 : the world of physical objects and events , including biological entities World 2 : the world of mental objects and events World 3 : the world of the products of the human mind
  16. 16. Critical Rationalism Critical Rationalism is the acceptance of human fallibility Critical Rationalism: Scientific theories , and any other claims to knowledge, can and should be rationally criticized, and (if they have empirical content) can and should be subjected to tests which may falsify them. Fallibilism Evolutionary Epistemology The mere fact that a theory has survived the most rigorous empirical tests available does not, in the calculus of probability, predict its ability to survive future testing Evolutionary epistemologists argue that units of knowledge themselves, particularly scientific theories , evolve according to selection Brian Skyrms
  17. 17. Is it really falsifiable <ul><li>Max Planck in his Scientific Autobiography and Other Papers, stated &quot; A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it.&quot; This view contradicts that forwarded by Karl Popper </li></ul>Newtonian Gravitation Theory: Predicts that every acceleration of every body can be traced to an interaction with some other body, according to their masses and the distance between them. What to do when we observe an acceleration that has no visible source? Is the theory refuted? No : The theory demands that the missing mass be found.
  18. 18. Duhem-Quine Thesis <ul><li>In the first half of the 19th century, astronomers were observing the path of the planet Uranus to see if it conformed to the path predicted by Newton's law of gravitation; </li></ul><ul><li>It didn't. </li></ul><ul><li>Possible Explanations: </li></ul><ul><li>Telescopic observations were wrong because of some unknown factor </li></ul><ul><li>Newton's laws were in error </li></ul><ul><li>God was causing the perturbation in order to show the hubris of modern science </li></ul><ul><li>Eventually accepted that an unknown planet (Neptune) was affecting the path of Uranus </li></ul>Theory-Laden: interpretation of observation is dependent on theory Dark Matter underdetermination of theories Pierre Duhem ( 1861 – 1916 )
  19. 19. Reductionism <ul><li>Complex system is nothing </li></ul><ul><li>but the sum of its parts </li></ul>Descartes argued the world was like a machine, its pieces like clockwork mechanisms, and that the machine could be understood by taking its pieces apart, studying them, and then putting them back together to see the larger picture. behavioral sciences should become &quot;genuine&quot; scientific disciplines by being based on genetic biology, and on the systematic study of culture (cf. Dawkins's concept of memes ) Daniel Dennett Steven Arthur Pinker
  20. 20. <ul><li>Thomas Kuhn on Scientific Revolutions (cf. The Structure of Scientific Revolutions, 1962.) </li></ul><ul><li>Kuhn argues that scientific advancement is not evolutionary, but rather is a &quot;series of peaceful interludes punctuated by intellectually violent revolutions&quot;, and in those revolutions &quot;one conceptual world view is replaced by another&quot;. </li></ul><ul><li>Paradigm: Kuhn’s idea that a scientific theory is not just a set of theoretical principles. It is an entire world-view </li></ul><ul><li>Examples of paradigm shifts in science </li></ul><ul><li>The transition from a Ptolemaic cosmology to a Copernican one. </li></ul><ul><li>The unification of classical physics by Newton into a coherent mechanical worldview. </li></ul><ul><li>The transition between the Maxwellian Electromagnetic worldview and the Einsteinian Relativistic worldview. </li></ul><ul><li>The transition between the worldview of Newtonian physics and the Einsteinian Relativistic worldview. </li></ul><ul><li>The development of Quantum mechanics , which overthrew classical mechanics. </li></ul><ul><li>The development of Darwin's theory of evolution by natural selection , which overturned Lamarckian theories of evolution by inheritance of acquired characteristics. </li></ul><ul><li>The acceptance of Plate tectonics as the explanation for large-scale geologic changes. </li></ul>Paradigm Shifts
  21. 21. Multiple Realizability Contrary to the famous claim of type-identity theory, it was not true that &quot;pain is identical to C- fibre firing.&quot; Against Type-Identity functional isomorphism = &quot;Two systems are functionally isomorphic if there is a correspondence between the states of one and the states of the other that preserves functional relations.&quot; Functionalism is a theory of the mind in contemporary philosophy , developed largely as an alternative to both the identity theory of mind and behaviorism . Its core idea is that mental states (beliefs, desires, being in pain, etc.) are constituted solely by their functional role — that is, their causal relations to other mental states, sensory inputs, and behavioral outputs. Hilary Whitehall Putnam
  22. 22. <ul><li>Walking along one day on the newly-discovered coast of Australia, Captain Cook saw an extraordinary animal leaping through the bush.    &quot;What's that?&quot; he asked one of the aborigines accompanying him.    &quot;Uh - gangurru.&quot; he replied - or something like that. Captain Cook duly noted down the name of the peculiar beast as 'Kangaroo'. Some time later, Cook had the opportunity to compare notes with Captain King, and mentioned the kangaroo.    &quot;No, no, Cook&quot;, said King, &quot;the word for that animal is 'meenuah' - I've checked it carefully.    &quot;So what does 'kangaroo' mean?&quot; &quot;Well, I think ,&quot; said King &quot;it probably means something like 'I don't know'...” </li></ul>Radical T ranslation / Indeterminacy of Translation I don’t know Source: Imagine you come across a new tribe in the Brazilian jungle, and the task is to interpret their language: to find out word-meanings and rules of grammar. This situation is entirely different from second-language learning. There are no familiar-sounding words, no teacher who speaks both languages, etc.
  23. 23. Two Dogmas of Empiricism <ul><li>&quot;a statement is analytic if it is true by virtue of meanings and independent of fact&quot; </li></ul><ul><li>No unmarried man is married (true by definition ) </li></ul><ul><li>No bachelor is married. (transformed into logical truths by substituting synonyms) </li></ul><ul><li>Necessarily all and only bachelors are unmarried men </li></ul>Analyticity and Circularity Quine’s Holism Quantum Logic Duhem–Quine Thesis Cats are animals evidence confirms or disconfirms not just a specific hypothesis, but a whole theory we do not, or should not, regard any sentence as &quot;immune from revision,&quot; since there may be circumstances in which the best way to revise our overall theory is to give up some sentence which had previously seemed unshakeable--even &quot;definitions.&quot; <ul><li>Belief in an analytic/synthetic distinction </li></ul><ul><li>Reductionism (every meaningful statement is equivalent to a statement about experience) </li></ul>
  24. 24. Holism Math logic The totality of our so-called knowledge or beliefs ... is a man-made fabric which impinges on experience only along the edges ... A conflict with experience at the periphery occasions readjustments in the interior of the field ... But the total field is so undetermined by its boundary conditions, experience, that there is much latitude of choice as to what statements to re-evaluate in the light of any single contrary experience ... If this view is right, it is misleading to speak of the empirical content of an individual statement ...
  25. 25. Claims (Lessons) from this talk <ul><li>Truth is almost unattainable </li></ul><ul><li>Theory of Meaning and linguistic plays an important role in our knowledge </li></ul><ul><li>Metaphysics as part of our knowledge is interconnected with other branches of knowledge and therefore is (not) falsifiable </li></ul><ul><li>Depending on your lifestyle philosophy can have pragmatic consequences for you </li></ul>