Chapter 1.4: Karl Popper and the logic of falsification

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[butterball]

These videos are one of the reasons that I love the internet. Free college lectures to continue my education.

[VictorGijsbers]

Lots of comments on this video, including some critical ones. Can't respond to everyone individually -- and sometimes the criticism is a bit amorphous -- but let me give an overall response and provide a link to a more in-depth engagement with Popper at the end. Now, first of all, this is a short introductory lecture. I'm in complete agreement with anyone making the point that much more could be said about this issue; that we could delve into Popper's overall story about induction, his notion of corroboration, his ideas about observation, and so on. But -- and this is crucial from the perspective of education -- none of that would change the basic point made by the video. In philosophy of science, it is not at all controversial to state that Popper's attempt to do without induction is, in the end, a failure. It is a failure for multiple reasons, but in part because of the reliance on inductively established beliefs in the performance and interpretation of any experiment. So, yes, Popper would have a lot to say about my video. But, no, it would not substantially change the outcome. And this is not a private opinion of mine, but a widely held judgement among philosophers.

Now some of the people who left comments on this video suggest that philosophers in general have misunderstood Popper. This is a myth, a myth that has been created and popularised by Popper himself. I'll just quote from his text Science: Conjectures and Refutations: "Criticism of my alleged views was widespread and highly successful. I have yet to meet a criticism of my views." Or again, from the first page of Objective Knowledge: "[...] those works which take notice of my ideas usually ascribe views to me which I never held, or criticize me on the basis of straightforward misunderstandings or misreadings, or with invalid arguments." However, Popper's views on induction have been criticised by some of the best philosophers of science of the 20th century, and if you read them side-by-side with Popper, it's clear that they have perfectly understood him. I especially recommend Wesley Salmon's "Rational Prediction" and Hilary Putnam's "The 'Corroboration' of Theories" if you want a taste of this literature.

[scottmcmaster]

The speaker has misunderstood Popper. Popper was not speaking about practice, he was speaking about epistemology. He recognised that in many cases individuals in practice were not performing science as he described it, but that he was making clear how knowledge was being acquired. Freud for instance did not conduct science as Popper described it, but he also did not acquire much knowledge via his attempts to only affirm his theories that were highly variable.

Popper also recognised that there were many underlying theories regarding measurement involved in every attempt to falsify.

I suggest that those who want to understand Karl Popper not turn to this video (which is confused), but rather read Oxford Physicist David Deutsch, who has clearly expressed Popperian science in his book: The Beginning of Infinity.

[alexanderpowers]

The complications critique misses a more relaxed requirement that a hypothesis be at least falsifiable in theory to satisfy Popper. Obviously complications can confound a given instance of an observation. But these are two different thresholds. So Popper holds.

[nileshoak]

It is amazing how many simply fail to comprehend simple point of Karl Popper. This presenter is no exception. Oh, well, at least he is trying and those more curious will read Popper in the original (multiple times).

[torguttormsyvertsen]

“The belief that there is only one truth and that oneself is in possession of it seems to me the root of all the evil that is in the world”
― Max Born (1882-1970)

[ryanreed]

Respectfully, I believe that you have a mistaken conception of falsification. Induction is not inherently antithetical to falsification. The only requirement is that premises with an inductive structure are tested deductively. That test is the search for observational data that either establishes modus tolens or discovers a counter-example(s). Take for instance an inductive premise like [all swans are white.] It has an inductive structure because we are incapable of observing all swans, but in all of those cases we have observed swans - they have been white. This inductive conclusion could be starting place in the process of falsification. How do we proceed deductively? Look for cases in which we have a swan, but not white. We find a counter-example in Australia: black swan. Hence, the inductive conclusion has been proven false. However, let's say we take the inductive conclusion that all swans are either black or white. So then we decide to search the earth far and wide for five years looking for a counter-example, which could be a pink swan - for example. Alas, we turn up we nothing. What Popper says is that there is reason to believe, now, that the conclusion all swans are either black or white has truth value. Only premises/conclusions/theories which can be proven false, and have stood rigorous attempts at being proven false, are worthy of being considered as truthful. We have now not only all of the positive evidence that supports the conclusion that swans are either black or white, i.e. all the black and white swans we observed. But in addition to that, in the negative sense, we also have all the experiences in which swans that are neither black nor white were not found, which is also evidence. That's falsification.

As for the semantics, honesty and precision is key. And honesty goes both ways, both in describing and not purposely misinterpreting the meaning of a theory.

[juliuszmazur-machowski]

so clearly and simply presented, thanks! greetings from Poland ;) !

[shojaairtaish]

Can we use logic to prove or challenge God existence?

[xdjcfpj]

This helped so so much. I have to write a philosophy essay on this topic and I just could not get a grasp on it. THANK YOU

[charbeleid]

you described naive falsificationism which is not popper's theory

[MonaRafiei-hdjj]

Your videos helped me prepare for my exam! Thanks

[hosamtak]

could you please provide us with the references of the information mentioned in this video?

[martinguila]

On the pont that popper is wrong because there are scientists claiming to know stuff. My interpretation of Popper is that he was not interested in describing how the average or how the worst scientist does science. But rather how science works at its best and how we should do science.

[skaughteygames]

I'm no philosopher, so take what I say with a grain of salt, but it seems to me the speaker is incorrect in his idea that the frog theory makes assumptions. In the three examples he gave, each of them ended up changing the meaning of the words and over all language. First, to say "all frogs die after a week in the freezer" means that the total continuous time the frogs were in the freezer is one week. It does not at all mean that someone took them out during that one week and put them back before the week was over so that they are still there when you go to remove them at the end of the week and that you assume they had always been there for the whole week. It's not an assumption, its the basic meaning of the words. Secondly, the whole idea that "the freezer is working and it didn't die" is assuming is ridiculous. This is a hypothetical situation. Its not actually being tested in the real world. If it was you would make sure the freezer is working the entire time. If for any reason it breaks down, you would stop the experiment, fix or replace the freezer, then restart your experiment. Lastly, assuming the frog is a frog and not a toad is the same problem as in my first point. Its a case of changing the meaning of the word. A frog is not a toad. Granted, a lay person might misuse it to mean any four legged amphibian that similarly resembles a frog which might include toads, but regardless when someone says frog, most everyone who knows English thinks of the same creature. So I would say the speaker is just nitpicking to try and support his argument. I'm a nobody and have never even heard of this Popper guy until just now but even I'm pretty sure he knew what he was talking about and the speaker in this video does not.

[vitaliarmonica]

But isn't falsificationism still useful, given main variables known and estable? E.g. If all the frogs have the same -or, at least, main- characteristics, then the falsification may be correctly applied with an equal frog. And, therefore, inductionism and falsificationism would be mutually complementary (and Popper got wrong only for considering them mutually exclusionary).

[moogzoliver]

The statement that all scientists use deduction is not deductive...

[janeksobieralski]

im loving this stuff, i thought he was going to do in the direction of saying if scientists are only interested in falsification then he would have to spend his entire life acquiring every frog in existence and putting them all in the freezer for a week until he either dies or there are no more living frogs on earth, but his way was much better

[OlejzMaku]

You are missing the entire idea of iterative scientific process. All those supposed hidden assumptions are in fact included in the theory or in the rest of Popper philosophy you failed to explain. If the language of the theory is too vague to falsify, then the theory is unfalsifiable and need to be replaced with more precise formulation and falsification is attempted again. This process never ends. What is falsifiable and what is not depends on current state of the theory. If you are an amateur who don't know how freezers work then this naive theory can be considered falsifiable and Popper's prescribed methodology will in fact lead you to discover that freezers need electricity and other valuable information. If you are a professional scientist then you are somewhere else and need to use more precise language to squeeze out something new, but in that case these supposed hidden assumptions you are taking about are included in this more precise theory. They are not coming from induction but from previous iterations of scientific process. Theory converges towards something, which approximates truth, but we can never say we know the truth.

[jjgdenisrobert]

Your syllogism is incorrect. It should be: if T is true, then we cannot observe O; we observe O, hence T is false.