Misunderstanding falsifiability as a power philosophy of Scientism

KarlPopperI think that trying to find one slogan that captures all of science and nothing else is a fool’s errand. However, it is an appealing errand given our propensity to want to classify and delimit the things we care about. It is also an errand that often takes a central role in the philosophy of science.

Just like with almost any modern thought, if we try hard enough then we can trace philosophy of science back to the Greeks and discuss the contrasting views of Plato and Aristotle. As fun as such historical excursions might be, it seems a little silly given that the term scientist was not coined until 1833 and even under different names our current conception of scientists would not stretch much further back than the natural philosophers of the 17th century. Even the early empiricism of these philosophers, although essential as a backdrop and a foundation shift in view, is more of an overall metaphysical outlook than a dedicate philosophy of science.

For me, philosophy of science was born toward the end of the 19th century as Mach’s instrumentalism and baptised in the late 1920s by the Vienna circle’s logical positivists. Combining the fledgling 20th century trend of focusing on language with Russell’s logicism and the fledgling transformation of Mach’s views into Bridgman’s operationalism, the logical positivist rallied behind a banner of verificationism as the be-all and end-all of knowledge. Their gravest error, and probably biggest appeal to scientists, was the division of statements into cognitively meaningful and emotionally meaningful and declaring the latter as ‘worse’ than the former. Only statements that could be empirically verified were cognitively meaningful and all other beliefs like say metaphysics were meaningless or at best only emotionally meaningful and thus not worthy of intellectual discussion. A perfect power philosophy for the scientist, and although justifiable at the time as a backlash against the overemphasis that idealists placed on metaphysics, it was quickly seen as oppressive.

Karl Popper’s famous response to the logical positivists was primarily motivated by two factors, one technical and one egalitarian. Unfortunately, both motivations are typically forgotten by scientists and laymen who tout Popper. First, falsification was introduced not because it better captured the reality of how scientists justified their beliefs, but to sidestep the technical problem of induction that was most famously raised by Hume. Even today, if you look at the language scientists use, even in the most empirical sciences it is seldom of the form “we built this complicated hypothesis and failed to refute it” (unless it was the null hypothesis that was not rejected, in which case the paper is seldom published) but usually more like “we showed support for this complicated hypothesis that we built”. For Popper, corroborating a theory should carry no weight, so most publications would be deemed irrational. In fact, the only time scientists typically invoke falsifiability is when they need to make a powerplay, to degrade something they don’t like as ‘unscientific’ and thus not worthy of discussion. This is in direct opposition to Popper’s second motivation.

Although Popper introduced falsification as a way to solve the demarcation problem, he did not create the demarcation problem to provide more power to scientists. Although for Popper there were non-scientific things he considered nonsense, simply being non-falsifiable (and thus for Popper, non-scientific) did not make something nonsense. Popper had respect for metaphysics. This was why for a logical positivist pointing out that verificationism is not verifiable is a strong critique (since it makes the basic tenet of their philosophy not cognitively meaningful), but pointing out to Popper that falsifiability is not falsifiable is just an obvious observation. It is also why Popper’s conception of the scientific is much more subtle and harder to grasp without careful reflection. In particular, most beginners are tripped up by falsification’s difficult relationship with logic.

Let’s start with where logic and falsification play nice: finite unions and intersections. If you have two falsifiable theories P and Q then P or Q is falsifiable because you can show the disjunction to be false by providing two observations with the first falsifying P and the second falsifying Q. For conjunctions, things are even easier: if P is a falsifiable theory and R is any statement (falsifiable or otherwise) then P and R is falsifiable by any observation that falsifies P. The ease of conjunction should also raise the first cautionary flag for you: since we can graft on any nonsense to a scientific theory and still remain scientific, we would need an extra tool for cutting away the excess guff. Unfortunately, for technical reasons, Popper cannot allow us Occam’s razor, but this discussion would be too much of a tangent.

The easiest real difficulty to notice is that for Popper, scientific statements are not closed under negation. The easiest way to see this, is that if they were then you could take a scientific statement P and its negation not P would also be falsifiable then by our previous reasoning the tautology P or not P would be falsifiable — an odd predicament indeed. The lack of closure under negation is also what makes falsification not equivalent to verification else if we wanted to verify something, we would just falsify its negation and vice-versa. This also means (by de Morgan) that scientific theories are not closed under implication.

If we move to first order logic then things become even more difficult. In section 15 of The Logic of Scientific Discovery, Popper notes that as isolated purely existential statement like “there exists an object of type T” is unfalsifiable. However, singular statements like “J is an object of type T“, Popper treats as falsifiable because without them he has no way to introduce falsifiers or observations more generally. However, this means that the logically valid introduction of an existential quantifier in going from a singular statement like “J is an object of type T” to “there exists an object of type T” makes a statement unfalsifiable. Scientific statements are not closed under introduction of existential quantifiers.

These properties of falsification are not critiques, but desirable features for Popper. They also imply — if it is not painfully obvious already — that not all non-falsifiable things are ‘bad’ or meaningless. For example, logic and more generally mathematics are both closed under all logical inferences. Thus, even though some mathematical statements are falsifiable and thus could be counted as scientific, mathematics and logic in its totality is not falsifiable and thus non-scientific for Popper. It is however, incredibly meaningful, useful, and fruitful. None of this would be a surprise for Popper, for some reason there is the unfounded myth that he set out to demarcate science from ‘bad’ pseudoscience, but that is simply not the case. As he writes early in The Logic of Scientific Discovery:

The problem of finding a criterion which would enable us to distinguish between the empirical sciences on the one hand, and mathematics and logic as well as ‘metaphysical’ systems on the the other, I call the problem of demarcation.

Nothing in the above suggests that not being an empirical science is ‘bad’. Similarly, being falsifiable does not make something ‘good’: “my feet are currently resting on a pink unicorn” is a falsifiable statement — a false one, in fact, but that doesn’t make it interesting. Similarly, let us look at Russell’s teapot:

If I were to suggest that between the Earth and Mars there is a china teapot revolving about the sun in an elliptical orbit, nobody would be able to disprove my assertion provided I were careful to add that the teapot is too small to be revealed even by our most powerful telescopes. But if I were to go on to say that, since my assertion cannot be disproved, it is intolerable presumption on the part of human reason to doubt it, I should rightly be thought to be talking nonsense.

Although the statement is carefully crafted to be not easily falsifiable, it is falsifiable-in-principle: we could build a spaceship and send it to where Russell says the teapot is and check. However, we won’t do that because although falsifiable, the statement is simply silly. In other words, if you want to dismiss this proposition (or, equivalently, the beliefs that Russell designed the argument to mock), you do not need to appeal to falsifiability, you can just rely on the usefulness of the statement or on Occam’s razor (although Popper would not approve of the latter).

Don’t equate falsifiable with ‘good’ or non-falsifiable with ‘bad’; the mistake of doing so is a misinterpretation by those unfamiliar with philosophy. Next time somebody dismisses or defends something as non-falsifiable or falsifiable, ask yourself: “So what? Is the statement useful? Interesting? Well articulated?” Especially if you deem yourself a skeptic, take the time to be skeptical of simple demarcations and the unnecessary power they bestow.

About Artem Kaznatcheev
From the Department of Computer Science at Oxford University and Department of Translational Hematology & Oncology Research at Cleveland Clinic, I marvel at the world through algorithmic lenses. My mind is drawn to evolutionary dynamics, theoretical computer science, mathematical oncology, computational learning theory, and philosophy of science. Previously I was at the Department of Integrated Mathematical Oncology at Moffitt Cancer Center, and the School of Computer Science and Department of Psychology at McGill University. In a past life, I worried about quantum queries at the Institute for Quantum Computing and Department of Combinatorics & Optimization at University of Waterloo and as a visitor to the Centre for Quantum Technologies at National University of Singapore. Meander with me on Google+ and Twitter.

14 Responses to Misunderstanding falsifiability as a power philosophy of Scientism

  1. Jon Awbrey says:

    I guess I would recommend pushing your studies of the philosophy of science at least a little further back — to C.S. Peirce’s work on the Logic of Science. Here he introduced the concept of information as a key to solving the long-running problems of induction. At the same time, he restored Aristotle’s abductive inference to its place at the initial hypothesis forming stage of inquiry and relegated a more confirmatory style of induction to the wrap-up phase of inquiry.

    Moreover, Bridgman’s principles of operational definition are little more than attenuated corollaries of Peirce’s pragmatic maxim.

    • That is a very good point. I’ve only read a bit about Dewey and have experiences Peirce and James only in the context of compare-and-contrast to Dewey. Can you recommend a good modern source to get me started? Something that puts them in a historic context and sketches the original positions while also discussing some of the responses and developments of the last 125 years?

    • Tim Rappl says:

      In case y’all may be interested: The best handling I’ve found of the of the problem of induction was provided (ca 1900) by George Holmes Howison, in his Magnum Opus entitled “The Limits of Evolution, and other essays, illustrating the metaphysical theory of personal idealism” (free on googlebooks). Pertinently here, at p.35: “But now the crucial question is on us: What prompts and supports the generalization? It cannot be the facts; for, simply by themselves, they can mean nothing but themselves. What is it then? The implication is not to be escaped: the ground of every generalization is added in to the facts by the generalizing mind, on the prompting of a conception organic in it.” Also, apropos of Artem’s “one slogan that captures all”, I love at p.47: “Thus creatively to think and *BE* a world is what it means to be a man.”. To be sure, the arguments Howison provides leading to these positions are – and I’ve tried my damndest – “not to be escaped”. (?)

  2. Jon Awbrey says:

    That’s a tough one. It is best to read Peirce himself as soon as possible, either in the Collected Papers (vols. 3 and 4 are my favorites) or in the Writings : Chronological Edition. The philosophers who write most of the secondary literature tend to be shy of the mathematical and scientific background that it takes to understand a lot of what Peirce is saying.

    One of my favorite first readings was:

    Thomas A. Goudge, The Thought of C.S. Peirce, University of Toronto Press, 1950. Reprinted, Dover Publications, 1969.

    A recent edition of his 1898 Cambridge Conference lectures, with very useful commentary by Kenneth Laine Ketner and Hilary Putnam.

    C.S, Peirce, Reasoning and the Logic of Things, Harvard University Press, 1992.

  3. Jon Awbrey says:

    If you are fond of rambling blogoid excursi, you might take a look at my notes in progress on Peirce’s Harvard and Lowell lectures of 1865 and 1866 on the “Logic of Science” where he introduces his concept of information as the key to solving “the puzzle of the validity of scientific inference”

    Information = Comprehension × Extension

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  12. Over on Reddit, /u/hyphenomicon left a comment on this post that closed with nice analogy:

    I think the conclusion of that essay goes too far. Falsifiability doesn’t automatically imply goodness, and nonfalsifiability doesn’t automatically imply badness, fine. But often statements which are nonfalsifiable will be bad, because ideas can propagate either by holding up to scrutiny or by being difficult to scrutinize. Expecting a nonfalsifiable idea to be wrong is justified inductively and in principle in the same way that it’s justified to expect an animal with camouflage to be vulnerable to predators.

    I’ve seen similar reactions to this elsewhere, so I thought I’d preserve my response.

    I think that the point of this post was that bad statements that are non-falsifiable are usually bad for more salient reasons than just not being falsifiable. Pointing to one of those reasons is much more useful. Similarly, lots of falsifiable statements (including say all plainly false statements) are bad for various reasons even though they are falsifiable. On the other hand, there are lots of good statements that aren’t falsifiable. Think of any mathematical theorem: it’s useful not because it could be wrong but isn’t, but because you have a solid argument for why it can’t be wrong.

    So what is much more interesting are those ‘other’ reasons that make statements good or bad. Falsifiabiltiy is just too loose of a criteria to be useful.

    To me, it is kind of like when somebody defends their position with ‘free speech’. Sure, that is a point you can make. But if that is the only point you’re going to make about your position then I’m not sure if I want to listen.

    That being said, I really liked the camouflage analogy that /u/hyphenomicon closed with.

    Expecting a non-falsifiable idea to be wrong is justified inductively and in principle in the same way that it’s justified to expect an animal with camouflage to be vulnerable to predators.

    The only issue is, of course, that predators often camouflage themselves, too. And they do this to not spook prey and not to hide from other predators. So it might be better to base our inferences on a diverse set of criteria, not just camouflage: maybe look at the teeth, or the stomach, or better yet does the animal eat others? Similarly for statements: falsifiability might be an informative criteria, but usually there are much better and more salient metrics on which to judge a statement.

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