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Dialogue Between a Philosopher and Physicists Round Table Talk: Dialogue Between a Philosopher and Physicists Markus Gabriel Professor, Director of the International Center for Philosophy, Bonn University Hitoshi Murayama Kavli IPMU Principal Investigator, and Professor, UC Berkeley Yasunori Nomura Kavli IPMU Principal Investigator, and Professor, UC Berkeley Physicists Talk about What Science Is Murayama: I would like to thank Markus for joining us for this conversation shortly after your lecture.＊1 In our earlier conversation you pointed out that, precisely Markus Gabriel Hitoshi Murayama Yasunori Nomura speaking, what people usually attribute to Popper is not what he attribute to Popper and which science is about trying to understand actually said. So, one thing we can go scientists agree, is not really what we the phenomena around us. To for is to repeat my understanding of would like to do sometimes, especially understand this, of course we need how science is dened according to when we talk about big questions to take quantitative data on what is Popper, though it might not be what about the universe and so on. So, happening around us, and once we Popper actually said. Then, we can that’s why I would like to get your have quantitative data, you come up discuss what is your real response input on what we think the denition with a theory that tries to explain is on this denition. Is that the right of science is in a traditional sense and those data. thing to talk about? what kind of other thinking is going Once you have a theory that is Gabriel: Why not? That makes sense. on in the philosophy of science in the successful enough to explain all Murayama: So, rst of all, we are past and what your take is on this the data you’ve got, then you start scientists and we have been taught question. So, that’s one thing we can making further predictions out of the in a specic way what science is talk about. theory and then confront new set of about, how it should be conducted, Nomura: In fact, Hitoshi, do you and data to see if those predictions will and sometimes we nd it very me completely agree? Maybe not. agree with the new set of data, and if constraining. That sort of the narrow Murayama: Yeah, we’ll see. they don’t, you say“, Aha, I falsify this denition, which we normally Gabriel: Maybe both of you try to just theory,” and this is the process, which state what you think science is, and we were taught, I thought by Popper, ＊1 On June 11, 2018, Markus Gabriel gave a then I map this onto a philosophical as the denition of science. talk entitled“ Science and Metaphysics” at conceptual space. Now, if it does succeed to explain Kavli IPMU and IRCN joint seminar held at the Faculty of Medicine Experimental Research Murayama: Okay. Here is, I think, the new set of data, then you say, Bldg., on the University of Tokyo’s Hongo what I was taught in elementary “Okay, my theory is consistent with campus. This round table discussion was held after the joint seminar. school what science is about. The data.” I would never say my theory 12 Kavli IPMU News No. 45 March 2019 is true. Then, you repeat the process Anyway, I think the basic attitude years. until you hit the point that is again of science is always like that. We Nomura: I totally agree with the basic falsied. Then, you change your don’t care any language issues, as attitude, but the question is that of theory and then try to, again, address long as we understand what we are time scale. This is, for example, an all the data we have explained before talking about. In this case I don’t care origin of the statement that string to see if that success is still retained, if you say the theory is true or wrong. theory is not science. I do not agree and if it is, then you make further The fact is only that the theory that the denition of science includes prediction and then start taking applies in a certain regime in the condition that all these cycles data again and compare that to the certain precision. In some extreme must be completed within a certain data to see the theory is still right or cases, however, it may become time. Falsiability we talk about wrong. Again, you never say it’s right obvious that the theory is simply an should not be like this. Whether even if it is consistent with the data. approximation of another theory̶ a theory is science or not should You only say it’s wrong if it does not in the case of Newtonian dynamics be determined if it is in principle explain the data, and then you try the special relativity̶and then we falsiable̶especially if the theory to expand the theory further. This is must consider this new theory if we has a reasonable chance to be“ true” the process we are taught of what want to describe these cases. To me, ̶though we should of course keep science is about. this way of thinking is one way to trying to see if there are predictions Nomura: I think that’s agreeable. dene science. In this sense, science that can be tested in shorter time I think no scientist can say that“ I is very operational. Having said that, scales. disagree.” the denition of science, at least Gabriel: That indeed seems to be a Murayama: Okay. Maybe some twist? natural science, also includes the deep disagreement, and that’s very Nomura: Yeah, small ones. One process of trying to explain the same interesting but it’s a difference. thing is that you said we never say set of data by the smallest number of Nomura: Yeah, the difference is even something is true. Indeed, people assumptions. In fact, this last point is among scientists. sometimes make a statement like important because otherwise you can Of course, if someone says that “Newtonian Dynamics is wrong” just list all the data to describe Nature I don’t want to invest my time for because of the fact that the and call the list a“ theory.” something whose conrmation time real dynamics is, at least, special Murayama: That’s right. You can have scale could be 100 years, that’s ne. relativity. I think such a statement is one theory for every single data. It’s their decision, and I don’t have any misleading. Of course, this is a kind Nomura: Yes, that is the worst form objection. But I strongly disagree with of language issue and in scientist’s of“ theory.” Then you try to minimize the statement that people working approach, it doesn’t matter. I mean, the number of assumptions from on things that might take long time we don’t care if someone wants there, and then your theory will to conrm are not scientists, the to say that Newtonian dynamics is have an explanatory power. Such statement that some people actually wrong because of special relativity, a theory usually makes predictions, make. The statement is, in fact, or if someone says that Newtonian namely it does not only reproduce dangerous because no one really mechanics is true because it explains what you already observed but also knows future technical advancement phenomena very well in a certain something else̶as Hitoshi said; I’m and also some other predictions may regime. The fact is that you must rst just repeating it here̶and then you be found which can be conrmed at dene the word“ true.” We can use do experiments and conrm these a shorter time scale. this word to mean“ contemporary predictions. Murayama: As you know, I truth,” and then Newtonian dynamics A problem is that some people sometimes made such a criticism Round was certainly true, at least in the have gone too far. They say that only myself but that was not about string Table 19th century. Similarly, we can use if all these processes are completed, theory itself but more about the the word to mean“ true in a certain say within the time scale of 10 or 20 people who were doing it because regime for all practical purposes.” In years, then the theory can be called they have the attitude that they don’t this sense Newtonian dynamics is still science. need to bother making predictions true now. Murayama: Hopefully, within 10 or test them, and that’s the attitude I 13 was deadly against because then that’s complicated. At this point we are mind of an immaterial demon, this not a scientic attitude. It’s not the not precisely dening science in such hypothesis would easily explain all same thing as calling string theory a way that Markus can comment the data. However, there are innitely not science but rather calling certain precisely, but this may be the nature many other hypotheses which explain attitude of people doing string theory of the issue̶I mean, it may have a all the data in one fell swoop. nonscientic. I made that distinction. lot of aspects like Hitoshi mentioned. Nomura: Yeah, and this is the theory Nomura: Okay, good. Then I might And some of these aspects are no one can… have misunderstood you at some different from what we were talking Gabriel: It’s a very simple theory. It’s point. But I would still say that even about when we discussed falsiability extremely elegant. It’s very universal.
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