Scientific theories should require the ability to be falsified.

Introduction The question of Falsificationism as a necessary condition for science takes place against the backdrop of the problems of induction and demarcation. No doubt falsifiability is a virtue for theories, but as Pro admits it’s but one of many virtues for a theory. There is also fruitfulness, ability to solve internal conceptual problems, etc. All of these virtues along with what Pro mentioned and falsifiability, come in relative degree. Another way of saying that a theory has a high degree of falsifiability is that it is “less ad hoc.” Now it is not my contention that "less ad hoc-ness" isn't good for scientific theories to have. Rather my contention is that the virtue of "less ad hoc-ness" doesn't give a clear demarcation or necessary condition for science. There are also other virtues for a theory and it’s not obvious which one is best or even good enough to be considered as a necessary condition. Yet according to Pro, somehow falsifiability is the more serious virtue; it’s asymmetrical relative to all other virtues. In other words, falsifiability is king of the many virtues a scientific theory can possess, and so it should be a necessary condition for considering something to be science. It is this claim to the throne which I humbly deny. Why Falsification Is Not a Necessary Condition of Science Counter Examples There are many examples of scientific theories which aren’t falsifiable but I’ll just present three. 1) The phlogiston theory of combustion where phlogiston was emitted from substances when they burned. But when it was observed that substances actually gain weight when burnt, and it was here that scientists made the unfalsifiable, yet still scientific, modification that phlogiston had negative weight. 2) Lorentzian relativity preserves Newton’s unfalsifiable absolute frame. There’s even proof that Lorentz’s interpretation may be preferable in the future following the discoveries of John Bell. [2] 3) Unobservable entities postulated in physics such as fields and the early inflationary era to explain flat curvature and large scale isotropy. Such an entity is pushed out beyond our event horizon so that it can never be observed. [3] Assumption of Fallibilism The allure of falsifiability over the other virtues arises by way of assuming that knowledge must be deductively certain. But what reason does falsificationism give us to decide between a conflicting observation and the theory instead? If a hypothesis doesn’t forbid any specific observation then it’s taking no risks. But if that were true, then theories which ascribe low probabilities to specific observations without ruling them out completely are unfalsifiable and so unscientific. But nearly all scientific hypotheses are in terms of probability, not deduction! So falsification must be weakened significantly to probabilities with a tolerance threshold relative to each individual field of investigation. But often times this is a subjective “prior probability” rather than a generalized standard. Furthermore, an absolute measure of falsifiability can’t be defined since the number of potential falsifiers for any theory will always be infinite. For example, how falsifiable is Newton’s law of gravitation? It’s infinitely falsifiable! Quine-Duhem Problem In testing a theory by comparing it with observations, there are always background assumptions used in order to merge the theory together with the observations. For instance saying that iron always expands when heated assumes that we can find pure iron samples, or if we wanted to test Chargaff’s rule (bases C and G are equalled to A and T in all DNA samples), we assume many chemical techniques. Another example from an astronomical theory: we must predict the telescope’s orientation, its prediction also involves interconnected statements constituting the theory, initial planetary positions, assumptions enabling corrections to be made for light refraction from the planet in earth’s atmosphere, etc. Now the problem is that it’s always possible to blame one of these assumptions conjoined to the hypothesis H, rather than H itself. (Historical examples of this available upon request). There is therefore no asymmetry of virtues found here in favor of falsifiability, for it’s always logically possible to blame other assumptions involved in the test of the hypothesis rather than the hypothesis itself. And so falsificationism becomes no better than justificationism. Thus in the aftermath of the Quine-Duhem problem we can no longer describe falsifiability as a necessary characteristic of science, it can only be a behavior of science. Why Falsification Should Not Be a Necessary Condition of Science The argument for the normative claim, that falsification should be a necessary condition for science, is that falsifiability (or less ad hoc-ness) is asymmetrical relative to all other intellectual virtues a theory can have, and so therefore since it’s the best, then it should be a demarcation criteria for science. History disagrees. History of Science If falsificationism had been a necessary requirement for science in the past then some of the best examples of scientific theories would have been discarded in their infancy without being developed. 1) Newton’s gravitational theory was falsified by observations of the moon’s orbit, then Mercury’s. 2) Bohr’s theory of the atom was falsified by Lakatos (1970, pp. 140-54) showing that given current electrodynamics, the electron should collapse into the nucleus within a very short time. 3) Maxwell acknowledged that his own kinetic theory was falsified by measurements on the specific heat of gases (1965, vol.1, p.409). All the important developments in the theory occurred after this falsification. 4) Copernican revolution: there were many falsifications sustained here such as the tower argument, the fact that a spinning earth would fling objects into outer space. There was also the absence of parallax and also that observations of certain bodies doesn’t change size appreciably during the year. Copernicus had no adequate response to these, but he did have simplicity on his side! It’s therefore unhelpful for science if the extreme openness of falsificationism were made a requirement. For although ruthless criticism is recommended, its opposite, dogmatism also has a positive role to play. But now if both a critical and a dogmatic behavior can be condoned for science, then it’s hard to tell which behaviors are ruled out. Khun criticized falsificationism on these grounds. Falsifying observations are anomalies that are always present and are not in themselves a reason for abandoning a paradigm. Progress in normal science requires a certain amount of dogmatism and close-mindedness, a refusal to question fundamentals. For because nature is so complex and there are so many possible ways of investigating it, researchers will not make progress unless they have something that focuses attention on a few aspects of it and a specific way of approaching it. Otherwise there’s just too many choices and science becomes chaotic. So as an analogy, even if you are in a very leaky boat, you shouldn’t jump out of it unless a new boat is available (which may also be leaky, but less so)! Falsificationism is Too Easily Satisfied Astrology magazine “Your Stars” promised those whose birthday is on 3/28 that “a new lover will put a sparkle in your eye and improve social activities.” A clearly falsifiable claim. Any Christian claim that the bible is literal is also falsifiable. Thus falsifiability can’t distinguish between astrology and astronomy, creationism and geology, since both make incorrect predictions. Self-defeating The claim, “all scientific knowledge is falsifiable” itself isn’t falsifiable. So falsifiability is an arbitrary standard for science, not a necessary one. Sources 2. James T. Cushing, "What Measurement Problem?" 75 & see Popper, Quantum Theory, 30 3. John Barrow, “Science and Ultimate Reality,” 363