Concept of Structure / Structural Realism (contd.)

0:00 ...playable, but we cannot be sure about which fundamental properties is playable. So in both cases there is something which is intrinsic and unlawful. But the reason for this to be intrinsic and unlawful are very different. I'm not trying to combine the two, I'm just suggesting that given the fact that these two very different pictures lead in the same direction, what I try to do is using the two different strengths to capture something that is stable in both the framework, namely something that is a string sink, something that is out there because these objects constitute a system space that is behind in front of us. I think that fits with some aspects at least of scientific practice namely the fact that we do experiments, experiments are based on interaction, when you do an experiment in something, you don't experience the thing in isolation you group things, you make you generate an interaction that is, I don't know, I may feel interactive in a shared particle or something like that so why not thinking that the properties we are experiencing in this case are intrinsic in this It depends on the fact that you have many things around them. So you can still retain your idea of opening things around, but what they do depends upon the fact they're around them together. Okay, I think we should go on. Thank you. So, my last speaker, you are 30. You could speak to me. Is this on? Yeah. Thanks. Okay. Okay, so that's what the whole spectrum view is. Okay, thank you, James. We've had some talks about what you've raised, and that's a big place to confess that I'm not a gut individual.

2:30 I'm a very cautious individual, I'm not a gutsy one. So my talk is going to reflect that. So we have some very different ideas what structural realism is and I'm going to tell you what it is in my opinion. It is a veritable password in contemporary philosophy and science, a password that is used very carelessly. In my bibliography, I have some 50-60 papers on explicitly on structural realism that have been written or published since the year 2000, and I haven't even kept a particularly close watch on this development. So given this very frantic activity, it's not really surprising that very different things are meant by these two words, and in this paper I just want to comment on the some ambiguities that appear in literature, especially regarding this well-known distinction between epistemic and ontological forms of structural realism. I'll fly over the introduction of the distinctions that we've covered in previous talks, and then I'll focus on, first of all, the weird interpretation of epistemic structural realism, which has been marshaled ontological structuralism where ontological structural realism is construed as an alternative to epistemical structural realism that is motivated by considerations from the philosophy of physics and as far as I can see these considerations fail to motivate ontic structural realism as an alternative to much less radical realist positions such as epistemical structuralism or the kind of a realist advantage person. Now, if we ignore the prehistory, it all begins with John Warhol. I think John made a very good and well-motivated suggestion that we can reconcile the normative argument and the pessimistic meta-induction by focusing our realist commitments to structural theoretical content that is expressed by mathematical equations. And those equations exhibit some kind of continuity over even radical theory trends. And the slogan was, only the structure can be known, and the challenge of course is how

5:00 to make that precise. Now, however you read this, it seems like a epistemological position in the past. It refines the degree to which you can justify your realist beliefs. I think that's a very well-motivated intuition. Now, then along came James Sladerman, as we already heard. Now, he asked a presumably deep question. Now, in structural realism, and maybe some illogical metaphysical position, or perhaps some sort of mixture of it. And then he and my beloved supervisor argued for metaphysical reading of this on the base of these considerations from philosophy of physics and when the dust settled there was a misstructure now before i start hammering um let me anticipate what the time is going to look like um first of all i argue that um there's a natural interpretation of epistemic structuralism, and the resulting epistemic humility is quite different just from the kind of Ramsey and humility that the way they do is argued for, just to make contact with the future. Secondly, I'll argue that this almost metaphysical determination does not motivate or towards structuralism or anything as radical as that, although it may motivate to move away from object-oriented standard realism. Finally, I would argue that structuralist interpretations of this current physics, however natural they are, they do not motivate ontological structures within either. So my small ones are something like this. First of all, this OSR, ESR, are distinct in this artificial one. But it's distinct in that . And then secondly, the distinction between standard realism and structural realism, that dichotomy between these two seems to be a false dichotomy. There's much ground between object-oriented standard realism and realism about ontologically primitive structures. Right. So what is ESR and what is not? Again, the same approach, the same approach.

7:30 According to the world, if we ignore the prehistory, it all begins from conquering. There's good stuff in conquering to be a pro-creative to the real end. Now we've got in the Bernal Maxwell theory sheet, Poincare writes a very beautiful rhetoric that basically only the structure can be known and not the real nature of things. Now, in trying to make sense of this distinction between structure and nature, as Fred said, that's what the question is all about, trying to make sense of what structure is as opposed major. Now, John Morrell ended up appealing to Ramsey's sentences. As it happens, David Lewis also appealed to well, he already used all kinds of structuralism by using Ramsey's sentences. Lewis's structuralism was, as we heard, motivated or inspired by Ray Lankton's reading of Kant. And as it happens, Juan Carré was kind of a Kantian as well. Is that a surprising coincidence or something more. We just heard that it may not be a coincidence. Angelo, with Stephen French, our beloved supervisor, examined the idea that it may be more than a coincidence. They argued more specifically that multiple realisability of branch sentences, in David Lewis's sense of different properties having different, different properties having the same, very same causal profiles. This idea could make sense of the notion of hidden natures. But according to Lewis, the primitive property identities of predities remain unknowable even if our theory is taking the final theory of science. Right. Well, personally, I find this line very puzzling. I don't see why to appeal to such metaphysical, esoteric as quiddities in spelling out between the nature's amounts in ESR. I don't see why to appeal to such an idealized notion as the point of theory of science, where the starting point was a much more mundane one, namely, theory shifts in the actual history of science. So I think there's a much better actual interpretation of epistemic

10:00 humility in Nelson in terms of limited justifiability. I take this to be quite obvious. Unfortunately John listens here to comment on this. So the idea is that while there is traffic in natures of unobservable things. We are never justified in believing in the particular claims made in particular theories due to this recurring, allegedly recurring theory change. And for what it's worth, there seems to be some sexual evidence in world-wise for this John writes that and this immediately he says although this identifies the nature of life this theory describes the structure. Now, I don't think we can make any sense for Fresnel having misidentified the nature of life unless Fresnel did manage to say something false about the nature of life over and above the structure. In the Lewisian sense, for example, this nature-structure distinction, the way he understands nature-structure distinction, no theory manages to say anything about the real nature. So, I don't think that can be the sense of structure that moral had in mind. Now, in the paper, I don't know, I think it's slightly different to me today, but in the paper, Saint French argued that interpreting ESR in the Louisian terms still struggle with epistemic structure, really. there is some incentive to go for ontological structuralism, given the arguments that Leibman and French had given earlier. Now, never mind what the actual argument is in the paper by Angelo and Steven, it should be clear that the central premise is rather motivated. The The paper was entitled, Looking for Structure in Wrong Places, I think that's pretty good. And I now move on to consider these arguments by French and Leilman, beginning with the metaphysical undetermination argument. Now, if you are familiar with this literature,

12:30 you may know that this point really gets started with a very simple question. What are quantum lie according to our best theory. Now, I think Fred made a slight mistake here. The argument doesn't go quite as you put it. Rather, the argument goes as follows. Well, according to our best physics, we don't really know what the quantum particles are like, since there are two very different metaphysical pictures that are compatible with the quantum So according to one picture, you have individual objects, and according to the other picture, we are dealing with less familiar non-individuals. Nevertheless, the claim is that we can make some sort of sense of both metaphysical pictures, because Stephen French has recently published a book where I tried to do that. Hence, we have a kind of metaphysical under-determination, a peculiar kind of underdetermination, where what is underdetermined is the most fundamental ontological characteristics of these quantum objects. And arguably the realist who recommends belief in such an ambiguous ontology is in trouble. So you should forget about objects whose nature is under-determined, and go for ontologically primitive structure that, in some sense, arguably underlies both metaphysical pictures. Now there are many potential problems with this, but I will focus on the following. Now, before we go on structural, I think it is natural to wonder how much the realist should be able to say in answering to the question, what is it once about? According to French and Ladyman, a realist should be willing to say quite a bit. For otherwise, the realist is very serious, they say. That's a nice one. The realists should give a full answer, they say, explicating the metaphysical nature of these entities in terms of identity and individuality and so.

15:00 Now my response to this, I think we can respond by first of all questioning why a full answer is required to this kind of question. Okay, well perhaps there is some motivation here to move away from object-oriented realism since if your commitments are to entities perhaps you have to say something about what you mean by an entity but it seems to me that we can quantify our realist commitments not in terms of entities but in terms of properties that are instantiated in well whatever they are instantiated in I think we can be agnostic about a level of metaphysical detail as long as our commitments are enough to explain the success of science and that I get that from the normal slogan and that's I take that to be the motivation for realism the only good argument for that so everything hinges on explaining the success of science metaphysical untermination seems to be quite different from the good old empirical intermination. There's a reason why empirical intermination is prima part is so threatening. Well, it's pretty indiscriminating and rampant. For any proposition P, in some theory, you can arguably construct an alternative theory that you know it's P, but it's entirely clear. Now, metaphysical intermination, by contrast, is pretty it's not perfect at all. All the metaphysical natures of things aren't exterminated. And there's a significant common denominator to these different metaphysical pictures. To go through this dialect in some detail, let's see what our French lady would say. What is this challenge of earth's access? Well, they challenge the sort of move by arguing that you deflate your realist commitments. You take your comparative magic realist statements, there are electrons, there are parts, all these things exist. They just become metaphors or something like that. Unless the very object of these entities is metaphysically pinned down. That's how I understand the charge of versusism. So the way they put the challenge is this. You think you can't

17:30 sense of the impact of quantum mechanics, for example, without taking a stand regarding these metaphysical natures of oddly behaving quantum margons. But it seems to me that asking to make sense of quantum mechanics is an ambiguous question. On the one hand, I can interpret it as a request to say what our world could be like to make the theory true, technically true. On the other hand, if I can interrupt this question as a request to explain what our world must be like for the success of this theory not to be miraculous in some sense. And I think it's a natural interpretation regarding success of this theory And it seems to me that we can account for the success of quantum stachistics, for example, at a level of properties that are common to both individuals and non-individuals' interpretations of this theory. Detail are quite complex. I'm trying to, I've been reading Simon Saunders on this, and as far as I can see, he manages to do something like that. He explains quantum statistics in terms of the discrete measure of the state space, and it doesn't appeal to metaphysical natures. But I'll just illustrate this idea. It's quite simple, really. I mean, And you can say, what's your general theory of relativity and the nature of space? Now, that different substance time is the interpretation of this theory, depending on how the identity of space-time points is construed across possible worlds. So you have hexaetist and non-hexaetist substance time-lism, and now it's contention, but French and Neyman consider this to be a case of metaphysicology determination. But to understand, when a theory is successful, that is, I mean, explained as a predictive success, it seems that we can appeal to properties of space time, such as its curvature, that light travels along the geodesics and so on. And these properties are common to both different

20:00 metaphysical interpretations. And we assume furthermore that these properties have correlates whatever the point structure of space is at a long scale. We don't want to take TTR to be a literal truth about this theory given from quantum reality, from quantum reality and the incompatibility of it. So these metaphysical interpretations regarding point identity seems to go over and above in a way that is under-determined by the physics perhaps, but it's not troubling in the same way at all as the old under-termination was regarding whether you believe in the currency of space-time as opposed to uh there being extra forces that uh play with your rules right i seem to be going pretty quick i have only two slides left so we'll have plenty of time for discussion that's nice but uh just to make contact with um another uh previous speaker Here, let me finally comment on yet another alleged motivation for ontological structural reels. Many have argued that since the days of Asira and Eddington, the ontology of quantum theoretical relativity of both, perhaps, are best conceived in primitive structural terms. And as we saw, two large parts, this is fueled by fundamental role of symmetries in physics. So we have general covariance in GTR, and case symmetries in case theories, and permutation symmetry in quantum theory. And somehow those are understood in relational terms, and then people go on to say interesting things like objects are only known in the structures and for like that. And arguably, quite often I also read that the scientific realist should be able to accommodate the metaphysical needs of concentric physics, hence you should be on the logical structural realist. And some have gone as far as to say something like given the considerations from philosophy and physics, these considerations override the kinds of considerations that motivate the epistemic structural realism in the first place.

22:30 Personally, I'm very puzzled by this way of linking philosophy and physics and realism. I think that the lesson from the history of theories was meant to be that we are not justifying believing the literal truth of our theories. We are only justifying believing what theories say about, say, abstract structure of the world or perhaps move between reliable properties or something like that. Why do you think that the concept really would make huge the structural metaphysics of our best contemporary theories, however attractive they are, even the cautiousness of, epistemic cautiousness of these theories? So that's a question for arguments like this here. Now, I'm honored to have the opportunity to be the last speaker. I'm ashamed of having presented a really good talk about that. Thank you. So, questions? The standard version of the mirror bar, so we have the empirical and technological success of science, how are we going to explain this? Well, science tells us some of the concepts of, say, algorithmic theories or physics are spoiled. If you're a structural realist, you must be saying that, well, it's the structures they have right. Now, if you're not committing yourself to making this ontologian claim, then you remain the epistemic structure of realism. How can you ever speak even a miracle of this? I don't see it. I don't see this. Well, the structures in moral sense, for example, seem to be mostly realizable in a very straightforward sense.

25:00 structures can be realized by many of these ontologies. Now you are just agnostic about whatever ontology it might be that fundamentally realizes the structure. Nevertheless, the structure is realizing that that's the model, that's the plane to knowledge of the world. I don't see the problem of . You can explain the structure of science by appealing to structures in the world sense, which I don't think, incidentally, that you can do, if you could do that. I think that would be a valid way of Without having any ontological commitments to structures, anything more than abstract I mean, it's quite a good idea, he's ambitious about this, but perhaps we used to talk about the structural properties of people like that, that are realized by whatever he is. So I was just wondering what someone lately might say about your last point, but I think what he might just say is that, to the realist, he might just say, well, I mean, what else about science, then it can take any ontology seriously as the apparent ontology of science. So that would be why it could take contemporary ontology seriously. And it may lead to making a tailored argument to the science degree. So in the days of Fresnel, for example, we would have taken ether seriously, and we would have been seriously misled by that? Yeah, I guess he would say the next part of the world is that You should be inferring things that science doesn't seem to claim, and you should be inferring things that we, or at least if you infer, so, I mean, you can have a native part that says you should be inferring, you know, actions in the void when science doesn't seem to require us to infer that, and then if you argue to infer anything, then infer something that's a bit closer to what science seems to suggest. I mean, maybe he would agree that in my case we shouldn't have heard, but at least he would have said that we shouldn't have heard something which wasn't quite right here.

27:30 Right, it does seem to me that if you take, it's presuppositively in this debate that you take these instances of pessimistic induction seriously, to me that if you if you buy into that premise and if you think that we are really in the same boat as uh regarding our trend space theories we are the same boat as brennan was uh at this day or as black lives was regarding of the um whatever it was taken to explain it. So if you take that in premise seriously, then I think you should be cautious in that. Yeah, I have a question about the first structure, the first argument for haunting structural realism, which is to attack epistemic structural realism, and of course that presupposes that the disjunction is true, namely that either epistemic or haunting structural realism is I find it remarkable that that kind of disjunction doesn't get questioned more often. The disjunction says that either we are epistetically limited to only no structure, or that there is only a structure. It strikes me that the common sense attitude is pretty theoretical in terms of this debate. And to that disjunction, we have been rejected altogether as a purely false. The common sense view, at least, takes out that they're both false. So I think the first kind of strategy for the pandemic, on the construction view, that presupposes something that at least strikes me as big, very gladly, ought to be false.

30:00 I read French and Lehman as arguing that, okay, we have good reasons for epistemic structuralism, so we go further than that, and then my specific argument shows that we should go further than that. It's not only that we have knowledge of polystructure, but structure is all there is. So they don't present the argument quite in that way, that there is this dichotomy that we have to choose. They take, I guess, premises that epistemic structuralism at least is well-multivated, and then the question is to recall beyond that. It would be more radical. Any other questions? There's one tension in the position which I think doesn't get sufficient attention, and that is, historically, it has been hugely methodologically fertile. I mean it's clearly been the motor of many successful research programs to take a preferred ontological stance very seriously and to push it as far as it can be pushed structural realism and either it's epistemic or ontic version were to become generally accepted default position in methodology of science what would you say about that circumstance that preferred ontologies have often been very much at the core of successful research programs. Right. Well, it's a fact about actual science. Yes, you just put that all onto the side of sociology and the context of theory. Fair enough. That's it. Lots of people are trying to do something else in science. It just seems to be the case if people decide to think, to believe in, in, in, in, in, whatever, in geometrodynamics or, yes, in the nature of things. In the nature of things, but given our epistemological system, it seems that we couldn't place too much, um, right, to justify it here. Any other questions? Yeah, cautious realism. If you, okay, if we shouldn't be justified by current science, I mean, and if you believe in the, as I call them, notoriously debatable consideration

32:30 of philosophy of science, the argument from the pessimistic data induction and the argument from theory under determination, a good attack on the structural realist position would be to cook up examples where you can show that there are positions or there are models where structural realists are in a position of underdetermination, in a scenario of underdetermination, or where structural realists also fail into the trap of NMA. Do you have examples like that? I can't remember any of them, but I know that it's an attack that has been made against structuralism by people like W.I.L. and others. I'm not a structuralist myself at all. You know, I try to make sense of it, and I see that we hear about so many kinds of structural realisms and I find that term is carelessly used and people carelessly draw connections to between these positions and yeah, I'm just a commentator. I don't think any of these. But some of these positions are better motivated to another. I'm still a fan of Ronald's original motivation, or systemic structuralism. I'm not a fan of, as you can see, I'm not a fan of ontological structuralism, just fancy for motivation. I am a fan of, I try to get some sort of structuralist metaphysis of the world, but as a realist I don't see why I believe that in this world there are ontologically primitive structures. I don't think I'm justified to believe that, given the structures of time. And that's the only thing that drives me to go beyond the phenomena. Let's check our details. Can we go and have some tapas now?

35:00 Here's the Pope. Careful, look. See outside, I'm just going to run to another room and get to it. Yeah, yeah, yeah, and shot there as well. Oh, that's good. Alright, I just need to run and get my record. I'll go from straight back. Michael, I'll be in the long picture. Sure, no problem, me too. Hi, thank you very much, that's extremely kind of good, thanks a lot, cheers. I'll go down.