Some of the most obviously correct physical theories  namely string theory and the multiverse  make no testable predictions leading many to question whether we should accept something as scientific even if it makes no testable predictions and hence is not refutable. However some farthinking physicists have proposed instead that we should give up on the notion of Falsifiability itself. We endorse this suggestion but think it does not go nearly far enough. We believe that we should also dispense with other outdated ideas such as Fidelity Frugality Factuality and other F words. And we quote a lot of famous people to support this view.
['Astrophysics - Cosmology and Nongalactic Astrophysics', 'High Energy Physics - Theory']
A Farewell to Falsifiability
{'A Farewell to Falsifiability': "Ali Frolop, ∗ Ali, † and Frolov ‡ (Dated: 1st April 2015)  \nSome of the most obviously correct physical theories - namely string theory and the multiverse - make no testable predictions, leading many to question whether we should accept something as scientific even if it makes no testable predictions and hence is not refutable. However, some farthinking physicists have proposed instead that we should give up on the notion of Falsifiability itself. We endorse this suggestion but think it does not go nearly far enough. We believe that we should also dispense with other outdated ideas, such as Fidelity, Frugality, Factuality and other 'F' words. And we quote a lot of famous people to support this view.  \nFoundations The evolution of scientific ideas is governed by several guiding principles. However, these principles can themselves change with time, as the tangled landscape of scientific knowledge develops. The question of what makes 'good science' and what principles we should be using to determine this, is probably most obviously exemplified in the physical sciences through debates about the nature of string theory and the multiverse.  \nBecause of the obvious appeal of these theoretical ideas, despite the lack of observable predictions, it has been suggested that it is time to retire one of the longcherished gold standards of science, namely falsifiability [1].  \nAlthough some scientists may see this as extreme, we believe it does not go nearly far enough. It is in fact time to retire several other scientific principles as we strive to accept the truth.  \nFundamentals String theory and its close cousin, the notion of a multiverse, can solve all of the existing problems in theoretical physics [2]. These include combining gravity with quantum mechanics, explaining the values of all the physical constants (including why the cosmological constant is at least 10 60 times too small), and solving many other fundamental mysteries [3]. It has become popular to attack these ideas for making no testable predictions [4]. However, although not widely discussed among physicists, there have in fact been published studies demonstrating experimental verification of the ideas of string theory [5]. Moreover, the nature of physical reality itself, and the existence of all the known particles and their interactions, is surely proof enough.  \nThe multiverse, too, has been criticised for its lack of useful predictions. However, the idea that one should explain some of the mysteries of modern physics by inventing an infinite number of entire universes seems quite natural to us. Although some accuse the proponents of the multiverse of being mere purveyors of science fiction [6], that is simply small-mindedness. Instead, we would suggest that the great advantages of extending the Uni-  \nverse into the multiverse should encourage us to think even bigger than the multiverse [7]. Indeed, even a cursory search shows that this concept is being widely discussed in the literature [8], as people come to terms with what to call a collection of multiverses [9].  \nFalsifiability Karl Popper [10] is usually credited with introducing the idea of falsifiability as an important demarcation criterion for deciding what is scientific and what is merely something else. However, Popper's work first appeared in the 1930s. Are we to suppose that any ideas before this period were incapable of being proved to be scientifically sound, because falsifiability was yet to be invented? The answer is obvious 'no', because Popper already knew which theories were correct, and so he invented this idea of testability to shore up some of the shakier theories of his time. However, now that the merits of the string-multiverse are so self-evident, we feel confident that if Popper were alive today, he would never have introduced the obsolete notion of Falsifiability in the first place.  \nOne of the examples that Popper gave for an endeavour that is demonstrably unscientific is astrology, which he thought to be entirely unpredictive [11]. However, as Thomas Kuhn pointed out [12], the case is quite the opposite. Astrology is falsifiable, and there is nothing magic about this demarcation criterion. However, Kuhn thought that science and scientists are mostly concerned with finding and solving puzzles about the world, which is of course not true as we explain shortly.  \nMoreover, the idea of falsifiability has always had a basic flaw. This is an obvious problem of the 'strange loop' sort [13], i.e., if we take Proposition A to be 'All correct theories contain falsifiability', but then add Proposition B, which states 'Proposition A is itself a theory', then we realise that we're in trouble.  \nWe therefore reject the requirement of Falsifiability. But there is more.  \nOther Fs Several other notions are usually considered to be inviolable by practicing scientists. However, we consider these also to be oversimplifications whose time has now come to be challenged - they are spherical sacred cows, if you like.  \nOne such idea is reliability or repeatability, which we might call fidelity . We have come to expect that a good scientific theory should give the same answer each time a question is asked. For example, 'Will the Sun come up tomorrow?' should have the same comforting response each time. However, string theory contains a much richer  \nphenomenology. The landscape of string vacua contains something like 10 500 possibilities. Therefore the experiment of making a universe will give a different answer each time. And so we see that we should also give up Fidelity.  \nAnother idea is simplicity [15], or theoretical frugality , sometimes referred to as Ockham's Razor. Carroll [14], the assassin of falsifiability, also suggests that the more preposterous the universe the better [16]. General Relativity (GR) is patently not simple, and string theory is to GR as a tax form is to a simple yes/no question. But given the enormous successes of string theory, it becomes clear that the best scientific theories should be as complicated as possible. Mathematical complexity and unfathomability should be criteria to apply when deciding what makes good science. In the same way, the idea of the multiverse is the very opposite of economy, proposing a fecundity of universes instead of just one parsimonious sphere of existence. On top of that, string theory requires many more physical dimensions than are accessible to the human senses, and yet there can be no doubt that these exist. Hence we should also give up on Frugality.  \nThe idea that lies at the core of most thinking about science, including both Kuhn and Popper, is that the ideas should not only be testable, but should pass those tests and hence be actually correct. This idea, which we might call factuality , has influenced scientists so much that Feynman once said 'I think it's much more interesting to live not knowing than to have answers which might be wrong' [17]. However, this has been misinterpreted, since the Universe - as we know it - is just a tiny piece of a vast entity described by the stringy-verse. What the  \n- [1] Carroll S., 'What scientific idea is ready for retirement?', http://edge.org/response-detail/25322 .\n- [2] Wilczek F., 2013, Class. Quant. Grav., 30, 193001, arXiv:1307.7376.\n- [3] And figuring out why your earbuds always get tangled up.\n- [4] See, e.g. statements by Freeman Dyson, Lee Smolin, Peter Woit, Doubting Thomas, Simon Cowell and Eeyore.\n- [5] Raymer D.M., Smith D.E., 2007, 'Spontaneous knotting of an agitated string', PNAS, 104, 16432.\n- [6] The first scientific paper to discuss the Multiverse was published over 50 years ago: Moorcock M., 1963, 'The Blood Red Game', Sci. Fict. Adv., Vol. 6, No. 32, p. 54.\n- [7] We could take the Latin root 'per-', meaning 'beyond' or 'completely', and combine it with the suffix '-verse'.\n- [8] One example arises in answers to questions like 'what would happen if Spiderman fought Superman?', since this involves combining the Marvel Multiverse with the DC Multiverse.\n- [9] Suggestions include 'omniverse' and 'metaverse'. A multiverse not restricted by conventional rules is the 'free verse'. One that is fooling us into thinking it is something else is the con-verse, etc. Many more ideas can be found on the 'inter-verse', e.g. at http://alldimensions.wikia.com/wiki/Category:Verse\n- [10] Popper K., 1959, 'The Logic of Scientific Discovery', Routledge.\n- [11] However, Popper's skepticism towards astrology is just  \nfather of modern physics meant is that we should not be obsessed with things being correct. As a famous philosopher of the 20th century said 'I'd far rather be happy than right any day' [18]. Hence we should seek out theories that are not even correct within the small piece of the multiverse where we happen to live. This enables us to free ourselves from the need to explain empirical data at all. Einstein once said 'Reality is merely an illusion, albeit a very persistent one' [19]. A statement often attributed to Fermi is that the poorest sort of theory is 'not even wrong'. So let us embrace that, reject the notion that a theory has to be correct and say goodbye to Factuality.  \nFreed from the fetters of rightness, string theory and the multiverse instead become matters of pure belief. This then is their ultimate triumph. By becoming faithbased science they reconcile those two great human endeavours - the 'non-overlapping magisteria' of Stephen Jay Gould - bringing together science and religion. As Einstein said 'I assert that the cosmic religious experience is the strongest and noblest driving force behind scientific research' [20].  \nFinish Ed Witten once called string theory 'a bit of 21st century physics that somehow dropped into the 20th century'. Presumably he was suggesting that string theory came to us from the future, but we think that a much more likely solution is that it came here from another part of the multiverse. Perhaps, then, there are other universes out there in which string theory is not only simple and correct, but even falsifiable as well.  \nwhat you'd expect from a Leo.  \n- [12] Kuhn T.S., 1970, 'Logic of discovery, or psychology of research', in 'Criticism and the Growth of Knowledge', eds. Lakatos & Musgrave, CUP, 1970.\n- [13] Hofstadter D., 1979, 'Godel, Escher, Bach: an Eternal Golden Braid', Basic Books.\n- [14] And we mean Sean Carroll here, not the mathematician Lewis, who once said 'I've believed as many as six impossible things before breakfast'.\n- [15] See, e.g. 'Simplicity in the Philosophy of Science', http://www.iep.utm.edu/simplici/\n- [16] http://www.preposterousuniverse.com/blog/\n- [17] Feynman R., 2005, 'The Pleasure of Finding Things Out', Basic Books.\n- [18] Adams D, 1979, 'The Hitchhiker's Guide to the Galaxy', Pan\n- [19] Not really relevant, but we realised that we hadn't quoted Einstein yet.\n- [20] Actually, that's a better quote, so ignore the last one.\n- [21] See some earlier papers with related ideas: Scott D., Frolop A., 2006, astro-ph/0604011; Scott D., Frolop A., 2007, astro-ph/0703783; Scott D., Frolop, 2008, arXiv:0803.4378; Scott D., Frolop A., 2014, arXiv:1403.8145.\n- [22] Comments on this paper should be sent to the lead author, Dr. Frolop."}