NATS 1700 6.0 COMPUTERS,  INFORMATION  AND  SOCIETY Lecture 3: The Method(s) of Science  III : Falsificationism | Previous | Next | Syllabus | Selected References | Home | | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 |   Introduction A good place to visit is  The Karl Popper Web,  where you can find useful references to falsificationism.   Topics Shifting the focus from truth to falsity. On page 38 of his book (see Lecture 01), Chalmers defines very clearly the new approach, which was first proposed by Karl Popper in his classical text The Logic of Scientific Discovery (London, Hutchinson. 1968): "The falsificationist freely admits that observation is guided by and presupposes theory. [...] Theories are construed as speculative and tentative conjectures or guesses freely created by the human intellect in an attempt to overcome problems encountered by previous theories and to give an adequate account of the behaviour of some aspects of the world or universe. Once proposed, speculative theories are to be rigorously and ruthlessly tested by observation and experiment. Theories that fail to stand up to observational and experimental tests must be eliminated and replaced by further speculative conjectures. Science progresses by trial and error, by conjectures and refutations. Only the fittest theories survive. While it can never be legitimately said of a theory that it is true, it can hopefully be said that it is the best available, that it is better than anything that has come before." In a sense, falsificationism reduces the scientific method to the testing stage or, if you prefer, emphasizes such stage as the only one that really matters. Either a hypothesis stands the latest test (and then we keep it as viable until the next test), or it does not (and we toss it away). You can only 'disprove' a hypothesis. You can not 'prove it (that is, once and for all). However, Popper and falsificationists go quite a bit further. First of all, they raise falsificationism to the status of a criterion for deciding what is good science and what is not. Only hypotheses that in principle can be falsified are scientifically acceptable. If a hypothesis can not be tested, and thus subjected to the possibility of being falsified, then it is not a 'scientific hypothesis.' For example, "Popper has claimed that some versions at least of Marx's theory of history, Freudian psychoanalysis and Adlerian psychology suffer from this fault." (Chalmers, op. cit., p. 41). That is, they can not be rigorously tested, because they are not clearly, precisely, unambiguously stated. Another feature of falsificationism seems to be that it proposes the notion of progress in science. This is a very difficult issue, not only for the history of science, but for history in general. What is 'progress'? A good discussion of this fuzzy concept can be found in a great little book by E H Carr, What is History? (New York, Vintage Books, 1961). The topic is so complex that it is beyond the scope of the course. Here I will only make one observation. At least some formulations of the notion of progress appeal to what happens in the world of life, claiming that evolution too marks the 'progress' of life. This is simply wrong. Evolution is not progress, but transformation in terms of what is most adaptable to the environment at any given time. If we could claim that the environment is 'progressing,' then maybe we could speak of evolution as progress. This, however, is clearly not the case. Likewise, it is not at all clear that science progresses, although many scientists think so. We can perhaps make a more modest claim, that each culture and each age usually develops as good an account of the world as it is possible in that culture and that age. As we shall see in the next lecture, when discussing Kuhn's work, it is questionable whether it is meaningful to judge Relativity as progress relative to Newtonian Mechanics. Both theories represent perhaps the best possible theoretical efforts of the 20th and 18th century, respectively. Each one addressed the physical problems of the times in which they were formulated. It is true that Relativity is more 'accurate' than Newtonian Mechanics in the explanation of certain large-scale features of our universe. But then, those features were unknown to Newton. NASA still uses Newtonian Mechanics when calculating the trajectories of its solar-system probes. Is falsificationsim the answer to our quest for a theory of how science functions? Is there anything wrong with falsificationism? Unfortunately, the answer to the first question is no, and that to the second is yes. One problem with falsificationsim is that it too does not realize that observations depend on pre-existing theories. Observations are obviously needed to test a hypothesis. But there is more. Clearly, a hypothesis that is more falsifiable is better than one that is less so. But how do we 'measure' the falsifiability of a hypothesis? Unfortunately this is impossible, because as Chalmers, p. 50, puts it, "the number of potential falsifiers [i.e. tests] of a theory is always infinite." Furthermore, it is probably impossible to falsify 'conclusively' any hypothesis, because the observations used to test any hypothesis may turn out later to be incorrect. Remember: observations depend on pre-existing theories, and these theories, although seemingly supported by evidence at a given time, may themselves be falsified at another time.   Ernest Ambler's Notes for the Cobalt-60 Experiment Does the history of science support the falsificationist interpretation? This is a much easier question to answer. Here are some examples: The Prion Diseases, Scientific American, January 1995 The Fall of Parity  1 The Energy Conservation Principle and Pauli's "Desperate Letter"  2 I will discuss here the third item. In the late '20s Enrico Fermi (1901-1954), an Italian physicist, was studying the disintegration of free neutrons--one of the building blocks of atomic nuclei. He observed  2  that the neutron would 'break up' into an electron and a proton. However, when he measured the 'energy' associated with these two particles, he noticed that some was missing. In other words, if you imagine the neutron as a bomb, with a known amount of energy stored into it, and after the bomb explodes you find that the energy of the fragments is less than the energy stored in the bomb, you must ask yourself where has the missing energy gone? Notice that the discrepancy Fermi found was no small matter. For centuries physics had been happy about one fundamental hypothesis: energy is never absolutely created nor destroyed--it is simply transformed (as when electricity is transformed into heat in a baseboard heater). This hypothesis had been so successful that it was (and is) known as the principle of conservation of energy. If Fermi observation was correct, then it would falsify this principle. After repeating his experiment many times, Fermi was convinced there were no errors in his observation. According to falsificationism, he should have tossed the principle of energy conservation away. However, he did not. Nor did most other physicists at the time. Why? To begin with, this principle is so basic to all modern physics, that its rejection would have forced physicists to rebuild a large body of well established knowledge. Many physicists preferred to think that Fermi observations were incomplete: maybe there was another fragment in the disintegration of the neutron that was particularly difficult to observe. In other words, physicists were more inclined to question the validity of the observation. Finally, a Swiss physicist, Wolfgang Pauli (1900-1958), made a concrete suggestion: there night be an unseen particle, the neutrino, which was responsible for carrying off the missing energy. This was another hypothesis which, if confirmed, would save the principle of conservation of energy. But, in order to be consistent with Fermi's observations, the neutrino had to be rather peculiar: it would have to have no electric charge and no mass, and interact with everything else only very weakly, thus explaining why it had not been observed by Fermi. The hypothesis was rather wild, and very difficult to test. It took a long time to detect the neutrino, but finally in 1956, at Los Alamos, it was found. To reject the prescriptions of falsificationism had paid off!   Questions and Exercises Find an example of a falsified theory which was not rejected. Why?   1  A great, easy to read, book which covers parity and a lot of related issues, is M Gardner, The New Ambidextrous Universe: Symmetry and Asymmetry from Mirror Reflections to Superstrings. Revised edition. 1991 W H Freeman and Company. 2  Fermi had been studying the decay of the neutron n which, as we now know, yields a proton p, an electron e, and an (anti)neutrino                . However he could not detect the (anti)neutrino .   Picture Credit: NIST Virtual Museum Last Modification Date: 07 July 2008