 Okay, so you're welcome again to this second OstraVeljana meeting. And our first speaker today is Rava Adreskav, who has finished his PhD at the University of Paris, one in France, and is currently a post-doc at the University of Salzburg, as well as Geneva, and he holds a prestigious Marie Curie fellowship. We are happy to have him presenting today. And his topic is probing theoretical statements with short experiments. So Rava, please begin your talk. Okay, thank you. So that's the work that started with my PhD, and now it's being published this year. So it's a big talk, so hopefully I can, how much time do we have? Normally, you have up to one hour, including discussion, as I had some practical introductions, so you have maybe a bit more, but the presentation itself, in the first instance, should be around half an hour or 40 minutes, and then we'll see according to whether the second speaker is ideal or not. Okay, good. So, thanks. So hopefully I could fit in as much as I would like to. Some of you have already heard, so hopefully also there's some new stuff in this presentation. Okay, so the problem of a scientific experiment started taking shape with cool and famous question, which was labeled as a paradox, this question. So how relying exclusively upon familiar data cannot go to experiment lead to new knowledge and new understanding of nature. And since we have a proliferation of accounts, and I will add one more today, which is the following briefly, so I thought experiment. I defend reveals and inconsistency in part of our previously held theoretical statements, and then the thought experiment or his critic offers a resolution and form of conjecture that might further investigation. So the experiment teaches directly about our theories and then from our theories we can learn about the world. So compare this to Brown's elaborate tax money at the instructive and the constructive and then the platonic which are both. So my account is in a way destructive and constructive for multiple experiments. So the plan of the talk is the following I'll set the stage with a famous case study the Einstein board for the box debate and the solvents meeting. And then from that I'll analyze the nature of the inconsistency revealed by thought experiments. And then focus on your terms elimination pieces. I'll criticize the strong reading and several other pieces of mountains, and then I'll pass to the positive part of the talk. I'll provide the common structure of food experiments and elaborate with three case studies I think I'll have time to one or two. Doesn't the focus on the cognitive process that are employed when we perform the thought experiment be them propositional or non proposition so I thought experiment is an argument or a mental model or not. It doesn't matter. So the upshot is, if I want to provide an stomach account for thought experiment, I have to locate. So, I locate the reliability of the experiment and the replicability and the replicability by the epistemic community something like pre experiments and I'll propose five strategies for the critic in order to show how they assess an incremental experiments and then I'll. Okay, so let's get started. Okay, Boris says that in 1929 somebody conference ice and proposed a good device indicated and triggered consisting of a box with a clock and the whole inside, and which could be open and closed by a shot or moved by mean of clockwork within the box. So the idea is that you let one particle escape, do you weigh the box with the equivalent c squared, you can have the energy of the particle. And then you look at the time you have the time that the particle escape from that you can know both the energy at the time of the particle which contradicts high the bridge. And both took it seriously and he said after a sleepless night, he came back with a reply and he said the argument amounted to a serious challenge and gave rise to a photo examination of the whole problem. At the outcome of the discussion, it became clear, however, that this argument could not be upheld. In fact, in the consideration of the problem, it was essential to take into account the relationship between the rate of the clock and its position in a gravitational field when known from the redshift formula. In this discussion, concentrated on the possible application of an apparatus incorporating Einstein device and drone to the eight. So this is born 1949 rendering of the survey of it. So what board did he better describe the experimental setup as it's clear from the figure. So the box official section is shown in order to exhibit its interior is suspended in a spring balance and is furnished with a pointer to read its position on a scale fixed to the balance support. The weighing of the box made us to perform with any given accuracy and by adjusting the balance to zero position my mean of a suitable law of suitable loads. So on the left here what you see is the mathematical mathematical derivation of words reply. And for the experiment what he did is simply that. So, the way it proceeds that we require the box and the clock to move in a gravitational field, and for says according to general theory of relativity. A clock when it's placed in the direction of the gravitational for which force would change its fate. So we need to conclude that the use of apparatus at the mean of accurate measuring the energy of the photon will prevent the strong control in the moment of escape. So here we have Einstein presenting a code experiment, which reveals which whose which output is in contradicts science will concentrate principle and work in the next day it says no you should. So the theory of relativity in order to understand how, how you should, how the clock behaves, and then it's consistent see vanishes. So how we should analyze this. So I argue that we should analyze how to experiment to give us an inconsistency, the nature of that inconsistency, and the role of the content of for the experiment scenario. So that I'll analyze pieces, mainly his elimination pieces, and I'll criticize the letter one, partly by drawing on 1973 article by Sheldon Grimsky, where he distinguished between internal and external inconsistencies. But before so let us look at northern argument view. And his first paper, he characterizes so experiment as follows, so they are argument with a positive hypothetical or contractual state of affairs, and they invoke particular irrelevant to the generality of the conclusion. So that second point bug me since the beginning and I try to understand it better. And here's what I understood at the end, that it's big in northern proposal. And here's why. So first northern tell us that to recover sufficient so this this characterization is only necessary and he says to recover sufficient condition for the whole experiment from this characterization, the nature of the particulars in two would have to be specified more closely. They must be of a type sufficient to guarantee the appropriate experimental character to the argument. So what does that mean before getting back to this recently so in 2018 bundle identified so five different thesis in northern view. So we have the identity thesis so put experiment are type and that the kill with argument. We have the reconstruction thesis with tell us that thought experiment can be constructed as argument with premises that refer to particulars. You have the reliability thesis that the semi-curiality of thought experiment coincide with that of arguments, and you have the elimination thesis which tell us any conclusions reached by identified with experiment. I'll come back to the elimination thesis more in a bit. And we have the empirical psychological thesis with the actual conduct of the thought experiment consists in the, in the execution of an argument. So, first, it's mainly in the northern account focuses more on the form, not the content. So we have the thought experiment which could be reduced to an argument, and in order to see if this conclusion is justified when you look at the form as a justified in kids. And you don't care about the content and this is very, and this is very clear in his not very clear in his elimination thesis is what tell us. The lesser extent and the identity thesis, this functional role of the content is fully considered. So I analyze this. So the green that's what I will be doing. So I analyze this by carefully looking at the nature of the inconsistency revealed by experiment. The content is also taken to be represented purely propositionally in Norton's empirical psychological thesis remember this tells you that the actual conduct of the thought experiment is the performance of an argument. And this is criticized heavily in the literature, for example in the mental model accounts may not tell us according to these account with content of the experiment is a mental kind that's not easily reduced the process a guy that contemplation often was an experiential character in which to think and manipulate a mental model in a specified way so as to produce. So my account will be pluralist concerning this cognitive process is you could you could you could manipulate proposition you couldn't manipulate manipulate a mental model you could imagine something and then see how it unfolds. So different people will do different things and this is irrelevant to Maya. Okay, so let's get back to this relevant part of Norton so what does he mean by party. So, and again in 1991 he tells us that the presence of these particulars. So, is what makes thought experiment experiment. So in one version of the thought experiment in which Einstein thought to demonstrate that the effect of acceleration moment those of gravitation so this is Einstein elevated experiment. He asked us to imagine a physicist observer who has been drugged and be awakened in the box. So that there is an observer that the observer is a physicist that the physicist has been drug that he is enclosed within a box. All these are particular which are relevant to the generator of the conclusion, which Einstein seeks to grow. Without particular such ideas, however, thought experiment would not have that experimental appearance. So now we can understand better what you mean by the elimination pieces, we have to eliminate all these particulars. And it's clear. So, this how he formulated thought experiments are argument which contains particulars irrelevant to the generality of the conclusion, thus any conclusions reached by a good thought experiment will also be followed by an argument, which does not contain the particular and therefore is not a thought experiment. So there are two steps here first you have the reconstruction pieces that any thought experiment could be reconstructed as an argument so let us call this a DE argument because it contains premises that refer to particulars. And the second one we could in principles. So the elimination thesis tells us that we can be able to transform the key argument into a non te argument that is an argument that does not refer to particular questions. There are two readings in the literature so this elimination thesis you have to be just claimed that you can eliminate some details and change other, but still keeping some experimental details. So put differently this reading is about the product of the thought experiment the conclusion is general, it's particularly free. It's however not about the process that leads to that conclusion. The strong reading tells us that even the process is particularly free the particular are eliminated in the non te argument that should replace the thought experiment. There are two different places where several places were not in as arguing for the weaker reading so it does that as a particular might be involved in a counter example to inner universally quantified assertion through which contradiction the conclusion is produced. And then in 2014 he says, if all that is required to be experiment, like the thought experiment describe an imaginary experiment and even racist execution, then that can be done by an argument. So I take it that some particulars in the imaginary experiments remain here. The stronger reading is also defended in 1991 for example he says, so Einstein black body radiation until doctor thought experiment, the conclusion follow from the premises. Thus we could find another argument which is not the thought experiment, but which still take us from premise to the conclusion. And this is the latest elimination pieces again. So the argument may well even be a reduction argument but not one of an experimental character. It's clear that such an argument alternative argument would be sufficient to find difficult to find because, because of the great complexity of some cases at least, maybe many cases. Okay, so what's the problem with the elimination pieces. So let's look at that. Let us, let's look at Trimsky's two notion of inconsistencies. So the context is proper criticism of body reply to Einstein photon box, so to expect on the one that we just saw. So proper rejects board appeal to attack and see a general activity to save the first theory quantum mechanics from the consistency of quantum mechanics, thanks for the box. He argued that this amounts to the strangest version that quantum mechanics mechanics Newton generated Newton gravitational theory. And for that, Trimsky replies that no wait a minute you have two different inconsistencies here. So, an internal inconsistency is a is when you have a set of theoretical statement let's say statement from quantum mechanics and Newton gravitational theory, they are internally inconsistent when we can purely, when we have a purely formal or logical inconsistency derived exclusively from the axiomatics of the theory. And then we have external inconsistencies. And here we have a set theory of theoretical statement is externally inconsistent. When it is applied to an experimental arrangement where upon a statement is implied which is logically inconsistent with one or more statement. So for external inconsistency, you need some particulars you need some content in order to apply your theories. And then Trimsky conclude there's nothing to do with the more if you take the, the, the thought experiment reveals an externally inconsistency because it's not at all strange that quantum mechanics and Newton gravitational theory be externally inconsistent with a drag to some experimental arrangement. But indeed it's strange if we see it as an internal inconsistency. And this would be the case under the strong reading of the elimination pieces where the experimental details are eliminated in order to transform both experimental and non theoretical. At North and seems to agree with the week of reading so in the lying to Bishop and this is this takes us to the identity ceases a bit. I think it decides Norton on on on the grounds of his identity first that the Einstein board of experiments are type. You should be could not be identified with arguments and northern do so I won't go into the details for lack of time and noted reply so I thought I'm bored to have two different but similar for the experiments and they correspond to do a different but similar arguments. They convert the experiment to one by ignoring the different space times of each, the different state time setting are then responsible for the different outcomes. If that is admissible, then the same strategy more for the arguments, ignoring premises pertaining to the space time setting the two argument profile proceed from the same experimental premises. They arrive at different results only because the difference in the presence pertaining to space time setting. So that is strange so how does that work, and what is left from the content of the resulting comment to the experiment. So it was experiment content only about the experimental arrangement. And this is even more perplexing, seeing that these details and not the theoretical statement unusually ignored in the elimination pieces. So the way I think is that you have one one thought experiment so I understand the design consistency and offer a resolution but more on that later in the account. It's been what 15 minutes I'm talking. Yeah, it's a bit more but you can, you have more than half presentation still. Okay. Let's let's look at another example to see to see a bit better this this idea. So here we have Paulie thought experiment that started with against board theory of the atom. So, this taken from because book 2013. Paulie considered the higher hydrogen atom with electric and magnetic field coming from same direction as in figure eight. So this gave this gave third. This gave certain allowed orbits deciding decided by given giving the appropriate values for the quantum numbers and kms and the quantum condition. So Paulie considered an adiabatic change to the system rotating the electric and magnetic field in opposite direction, as I figured you follow and following the rule of the diabetic principle. It turned out that by doing this a system could be achieved theoretically for which the magnetic quantum number m was equal to zero. But I'm different zero was stipulated as a necessary feature of the quantum condition. Clearly, I thought experiment that is aimed at revealing an external inconsistency in quantum quantum theory. So Paulie is applying general principle to the quantum condition and the adiabatic principle to describe an experimental arrangement traces execution. So the hydrogen atom with E and B fields. So the quantum condition allowed certain orbit, orbit to the initial system. And then the system is rotated following the rule of the adiabatic principle and we arrived at. So we're doing this we arrived at the system theoretical system with a magnetic quantum number and zero, and this directly interpret is directly interpreted as contradicting a necessary feature of quantum condition. So why, why is it external because we have hundreds of ways which we might apply electric and magnetic field to a hydrogen atom and then consider a possible adiabatic transformation without having amic will be zero. This is considered as an attempt to reveal an inconsistency in both theory. So for instance, when it's argued at the same time. So at the same period that Paulie thought experiment that was argued that the quantum condition that was it only discrete energy level directly contradicts theoretical statement from classical electrodynamics example which was a continuity of energy. And you get the sense that's different between internal and external so the internal inconsistency is in the second arguments and the internal role in the in Paulie thought experiment. So what about the resolution. Historically it wasn't followed because Heisman matrix mechanics and study their wave mechanics were changing the scientific landscape and we didn't need to provide changes to both quantum theory. So the idea is here that northern could defend his stronger reading if we can always be assured that we can transform an internal inconsistent in the internal one and northern things we can, but he doesn't provide any argument for that. So let's talk for now so what's what I've been arguing for is that northern strong reading of the elimination thesis but not, could not be kept. And in fact, more than argument view comes out stronger with the weaker reading, and I see no different element experimental character of thought experiment and northern sometimes alluding to. The liability season remain consistent with the weaker reading is just says that the argument can refer to premises that contain particulars. So granted that some particulars are not eliminated. Eliminable, then what are their functions that are several one of them. To me is most important. So these particular serve. They provide a way to group and apply theoretical statements, especially when this. So they come from theories with different scope, let's say thermodynamics and general activity and quantum mechanics. In order to describe an experimental arrangement races execution and the truth and interpreted speeds up. So how to, so how they do this. We passed to the positive course. So how to experiment with this. Well, I, I, I argued that they, they have this following common structure. So first you have the target question to scientist and identify a target question and use the sort of experiment to answer. For that he imagines a scenario unfolds that arrive at the result, which I labeled the OU, which one interpreted reveals an inconsistency, which then calls for a resolution. So not precisely the scenario you have the following element, you have the theoretical and that particular statement, either quantified or not depending on the problems of the science. You have experimental arrangement involving objects and things that happen to under perform my dumb. And you have the description also of the behavior of the theoretically under described part of the experimental arrangement. And the third part are like theoretically under described and then remain so in the scenario of the foot experiment. So how they behave is provided by the foot experiment and experimented by the author, and not by some theoretical statement or that described the behavior. So, and then we unfold the scenario. What we do here is we apply the theoretical statement into a, and the description and to see of the theoretically under described parts in order to describe and place the execution of the experimental arrangement in TV. So some clarifications here. So how we apply theoretical statement from a to describe and raise the execution of this imaginary experimental setup is case subject and context dependent. So different people will do different things in different cases and different historical periods. And as as Vendil put it. So there are some posterior acquire truth that function as implicit knowledge background knowledge enabling us to come to a relatively quick decision and the evaluation of a total experiment. And we'll see that this in the future and in the upcoming case studies, but we can always make these premises explicit by reconstructing the thought experiment as an argument. And this is useful, for example, when we are skeptical about the possibility of foot experiment. So this means that the reliability pieces could remain the ultimate by without committing us to the strong reading of the elimination pieces, nor to the identity pieces, nor to the empirical psychological pieces, and which bring me to my second. So that the to see in my structure is meant to capture the following. So not every detail of the experimental arrangement is, or even could be theoretically or empirically describe and paste. So the experiment we seem to go beyond to a to a other theoretical description. And this is something that's meant to capture by to see to see this so consider Maxwell's original demon you, he says also imagine a vessel divided and to with gas inside it, and then you have a demon who can see the individual molecules open and close this hole so as to allow only the fastest rifter molecules to pass from a to B, and the slower one from B to a. He will thus without extend his offer contradict the second law of thermodynamics. So then, how I understood the debate between northern and, and let's say the mental model accounts is concerning this. It's concerning this empirical psychological pieces. So, here are we entertaining the proposition so imagine suppose that the demon could measure molecules, molecules feed and manipulate the master's door. Or are we more in line with the mental model view when we perform the food experiment we really imagine. Objectually, magically imagine, at least not non propositionally a demon and then we picture in our mind how he behaves how he takes molecules, and how he opens and closes a master's door so only has to allow fast molecules to pass to one side and the slow on to the other. And so, I claim that neither is important, you could be pluralist different people could could unfold the scenario differently. And Cooper in 2005 argues, not for the same thing but in this quote she does so whether the experiment reason through the situation we are manipulating a set of the position or a mental picture makes no difference. So, let's get that theoretical question, you have the scenario with a theoretical statement with the experimental attainment the description of the theoretically under the right parts, the idealization abstraction and then you unfold this you follow you run this experiment in your mind being the propositions or mental images or what. And from that you arrive at the following to arrive at an output of the output, so that's the result in a way. So if the unfolding of the scenario is correctly done you arrive at the output which is a proposition, it's crucial to distinguish the result of such unfolding from the propositions, so step five and six. So step five is you have an inconsistency revealed by interpreting the output, and at the end of those experiments offer a way out inconsistency revealed in the form of a conjecture a hypothesis that might have further to be further explored and tested by future theoretical development and empirical confirmation. I think I said no so some of the clarifications to step four to six so the OU is propositional and it's analog to an empirically obtained observational statement that constitute the result of some real experiment, let's say. And it's in conflict with one more theoretical statement. This is why when you interpret it you get an inconsistency, and it calls for a resolution. Yeah, could you finish in five minutes. In five minutes. How much do you need, but we don't have. Okay, so let me skip the case studies. Or maybe one. Can I turn in the discussion of the questions about this. Okay. Okay, let me let me just one. Analyze one case study and then jump. So, I lost my train of thought. So the photo book photo experiment was was against the consistency of quantum mechanics. Here we have another photo book experiment which is aimed against the completeness of the theory. So how does it tell us, so how it tells us where we analyze Einstein that the complete theory assigns one and only one theoretical state to each state of a physical system. But in EPR type experiment involving spatio temporarily separated by previously interactive systems and be quantum mechanics assigned different theoretical state, different three functions to one and the same real state of a say depending upon the, upon the kind of measurement of the three hands quantum mechanics is incomplete and how I said the crucial step here is involved with proof that system a possesses only one and one real state. And this is just to follow from the conjunction of two principles locality and separability. Separability say that facial temporary separated object possess well defined real state locality say that such real state is unaffected by events and region separated in state time. Okay, so the third experiment is the following. You have an experimenter with various measuring instrument rides on a moving photon box which later come to rest. Now as before a particle escape through a shutter with a clockwork mechanism. However, now that experimenter will do one of two things. He can either do a precise measurement of the box position and does a prediction of the exact time when the emitted photon will be received at some distance location as, or he can make a new measurement of the books equal to the time at which case he or he or she can predict exactly the energy of it for them. And how it goes and this scenario as follows, so this is a letter to Ed Stein. So as soon as it has left the box, the light quantum represent a certain deal state of affairs about whose nature we must take your construct and interpretation, which is naturally in a certain sense arbitrary. This is essentially about the question should we assume that the solution subsequent measurement we made on be physically influence the fleeing light quantum. That is to say the real state of affairs characterized by the light quantum, where that kind of physical effect from the on the fleeing light quantum to occur it would be an action at a distance that propagate with superluminal velocity. Such an assumption is of course logically possible, but it's so reponent to my physical and that I'm not in a position to take it seriously. So in a different to put differently, both separability and locality here are used to interpret the fleeting light quantum separability as a state with it and independently state of affairs from the moment it leaves the box and locality negates as a separate sequence measurement made on the box could physically influence the fleeing light quantum. And then you conclude that quantum mechanics is incomplete. So in my structure it will be something like the following so just steps 456. So for remember the output of this unfolding so the result of the scenario. So we can in principle determine either the exact time or the exact energy of the emitted foot on depending on the measurement done on the box, however after the separation of the particle. And this is the, this reveals an inconsistency for Einstein so it's logically possible for Einstein but it's the point into his physical instance. That is for quantum mechanics to offer a complete description, either locality or separability or both should be given up. That is a different term, the thought experiment bring the light and it's learning consistency between locality separability on one hand and completeness on another. So Einstein resolves this inconsistency by saying quantum mechanics is incomplete and we have different resolution and the literature in the physics literature, which maintains completeness completeness and reject locality separability. Okay, so let me jump very fast. I wanted to just to show this so in a different photo books. So, you have a simple scenario and then when physicists try to elaborate how, how the experiment should be unfolded you have like eight equations, in order to arrive at the output. And this is why I'm saying so different people could unfold the scenario in a different way. It depends how, how much they understood the theory and how much they grasped it, and how they can apply it without explicit mathematical derivations. Okay, another case that I thought I had one hour sorry. If I'm not going to, to, if I want to remain pluralist concerning this different cognitive process and how different people could unfold the scenario differently. And then how to experiment are reliable. Well, I say that they are the reliability of experiment would should lie in that replicability by the stomach community so I'm a physicist I have the experiment that contradicts quantum mechanics. I put it out and then different people will try to see if really the, the unfolding is correctly done. So, let me jump this this is on step six. So, this just say that it's conjectural and how you pursue to resolve a given inconsistency is not linear but depends on many things and So, so I have the experiment I put it out. And then it contradicts from the mechanics and I say something. So the systemic committee want to assess it. They have different strategies so the first is worse strategy so the theoretical statement into a should be different here would tell us that that's not quantum mechanics. It's a new to generate it that should be used in order to understand how the clocks behave, but generate it. Remember, this is a man and the clock is not in front of us so we cannot see how it behaves so the dynamics of the clock let's say, will depend upon our theoretical knowledge. This will. This is the thing that will permit us to unfold the scenario. We could also so the second one would be to reject the behavior that the behavior of some experimental arrangement could remain on the describe so the history of Maxwell's demon on today, tried to naturalize the demonic process, either as a mechanical or a computer channel measure measuring and the raising device. However, I should say here that these naturalize both experiment are relevant relevant for Maxwell's original demon and its conclusion but this is another story, maybe that plus demon fits better here. So the third strategy would be to argue that the theoretical statements, not I, they shouldn't be changed, but they are not correctly applied. So it'd be so I didn't talk about this. I'm not talking about long ventrin, for example. Longva argue that by correctly by by correctly applying special relativity only one of the traveling twin will be younger than his brother. So in all these steps, the output of the unfolding no longer follows. You could also reject the idealization. So the Aristotelian could reject the idealizations and Galileo for him buddy. Northern analyze analysis of this version of Maxwell demon is falls under this one. And finally so if you agree to 1234, and you don't want to accept the conclusion scientists has also one remaining. Sorry, should be five strategies what remaining strategy so they bite the bullet they accept that there's an inconsistency. However, they provide a different resolution. Remember the resolution is only conjectural so Einstein thought that quantum mechanics isn't complete different scientists throughout localities availability and try to do other things. The paper I defended a new account of those experiment which characterize them as inconsistency the dealers and denominators. I provided the common structure, and I remain silent concerning the cognitive process that each and every one of us are going to employ in order to unfold a given scenario. I analyze the nature of the consistency reveal and the conjectural character of its resolution, and the natural question that follows that do also experiments and, at least in physics, maybe beyond share this analysis. And for that we should inquire of this. I think that if the inconsistency readings that is present in all the food experiment, and if yes, what the balance and if you know what the balance as well. Thank you. Thank you very much for that. For an interesting talk. We are sure that you have a lot to say if anybody has questions, because you have so many material. It's up to you. Yeah. Well, in principle, you should be able to mention in the chat whether you have a question by raising your hand. Yeah, and I see that Pierre has a question so please begin and the others, please raise your hand there. What was the chance that you have a question, and in total we will have 15 to 20 minutes. Okay. So please begin. Yeah, thanks. Thanks a lot. Thanks. It's also very nice to see you. Thank you so much for this. It's just a question about the, the last step, the resolution of its consistency. It's just a basic observation that usually when you have any consistency logically, there are several ways to resolve the inconsistencies you can give up several segments. And here you say that so I thought that your account, but maybe it's from memory that the first version of your account that I read or was presented to us, you stop at the inconsistency revealer. And I want you have you have this extra step of like resolving the inconsistency. And I'm curious about what is, what is the element in the, in the thought experiment that drives towards one particular way to resolve the inconsistency is the inconsistency, as opposed to the others. And the second question is, are there any ways to have any ideas about the reliability of this choice. You mentioned that the resolution is contextual at the end, but do you have any, any way to evaluate the reliability of this choice. I hope they make sense. So no, from. I think from the beginning I had this resolution step. Okay, good. I don't think the thought experiment could provide any rule that as to what to give up, but pragmatic choice from made by the author. So, take shorter EPR to experiment Einstein wanted to. So prefer to maintain locality and separability because it coheres better with his theoretical beliefs, while the evolution of physics, lots of people tried to get rid of locality or separability and keep completeness. So, I think, what's the second question. So, the second is, if there's, if there's one possibility that is that this is selected or like that is made more intuitive by the thought experiment, why is it reliable but you should tell me that the thought experiment does not by itself drive you towards one particular way to. Perhaps the second question doesn't arise. No, no, so the reliability is more focused on the consistency revealing step. The resolution is always conjectural and you can, most of the time you have separate resolution at hand. And this is what I skipped from the presentation. I would not like to more but this is enough for my character question and the other questions so I will leave it there. Thank you. Thanks a lot for what was it was good to see you. Yeah, you too. It's been a while. Thank you for this exchange. Does anyone else have a question. I don't know. Please write this in the chat or raise your hand. First, how it happens that I defended the page this is with Alexander G on the topic of how too much surrogacy costimeters with empirical symmetries and the empirical symmetries are actually what most of them were or still are sort of experiments. So it's a question like how to match the costimeters with some experiments or past previously. What was previously so to experiment. I have two questions on this. First, I saw you had a couple of slides towards the end about Einstein's elevator as this is one of the empirical symmetries on according to my topic I am very curious about what you have to say about this case in particular. So this is first, and second, I have another sort of another empirical symmetry which is also a sort of experiment, which is a modification of double slit experiment. So it observably you have what you have there is some equipment and an interference pattern. As an outcome of the experiment, but if you place a small man inside the experiment, then you will see how phases of two beams, which are passed, which passes through the slits, get affected by some the addition of some device. So there is a huge difference between the observable side of it, and the unobservable side, and the fact that you have a sort of experiment is what allows you to put someone in and imagine what this person would see if it was a small person and so on. So you were speaking about this in your presentation. So there's this crucial difference, which suggests that eliminating the thought experiment character of this happening is really changing the situation. And you were discussing cases like you eliminated this is still the same experiments I'm, I'm, it was not your position but I'm doubtful about this position. So please tell about this and about Einstein and a better case. And the second question I'm so I don't know the thought experiment in order to say more about it and I didn't really quite understand understand your brief summary of it. So, let me let me let me jump to the first one. So the first one if I understood correctly, you're labeling the equivalence in Einstein elevator the symmetry as an as an as empirical. Classified as an empirical symmetry because it could take place in the world. Okay. So this is how I understand this thought experiment. So, at the time that Einstein thought about the third experiment, we only had special relativity. And so he thought okay, let the guy be at the empty space, pulled by demon. Could he tell the difference between gravity and acceleration. So they all and then you have to two observers of the inside and the outside one. And the inside will tell you will say no I'm in a gravitational field object behave as if I'm on earth. And the outside observer will say no he should be an absolute motion. So, why does the outside observer says that he's an absolute motion because he's relying on special relativity or Newton mechanics in order to analyze the behavior of these objects, let's say. So, seeing that this is a thought experiment the imagined events are placed using our theoretical and empirical knowledge. So that shows Einstein that you have an inconsistency between this observational equivalence between the what the inside observer sees and the theoretical difference that the outside observer is applying to the scenario. How can I say this better. Put it out, I think it's better if we hear it from Einstein. So, the man and the, so the output of this thought experiment will be the following the man in the chest and the elevator will conclude that he's in a gravitation. And then in consistency that this output is inconsistent with Newton mechanics and special relativity, because in these theories we ought to conclude that the man is in his conclusion, and the only possible description that the man should say in the physicist and the lift is that he's an absolute acceleration. And I don't know if this answers your question I went a bit away from from the snow. It looks like you answered to the second question by using the first question. So you do say that there is a difference between what's going on inside which is observational and like the theoretical explanation of this which takes into account what goes outside as well. That's how I understood you. No, so the outside observer is relying on special relativity and Newtonian mechanics in order to say that the inside observer should judge that he's an absolute motion. For Einstein, this, this is absurd because the inside observer could perfectly say that he's an aggravitational field and this is a very consistent thing to say for right. That shows him that the notion of absolute. The notion is of absolute acceleration should be eliminated from our theories. That is the purpose of the third experiment. And then he resolved this inconsistency by postulating the equivalence principle. But I'm not sure if the third experiment can can force this conclusion is it. I think I'm talking more about the review the inconsistency revealed and you want to know more about the resolution step. But cannot we you are speaking about the subjection which, which is made by someone who is outside the elevator and who is using special relativity and so on. But if, if the resolution is as Einstein proposes, then couldn't we also imagine another outside observer who relies on Einstein theory and who sees the elevator being in the in the field of some massive body and then the explanation still works. So it seems like the objection goes only it can come from two sources either from the theory you use. So is this special or general. And secondly, from what you see outside so these are two unrelated things because if you see that the elevator is actually accelerated by some mechanism when you see that from outside then you say it's accelerated when you see that in the, that it is in the field of some massive in the proximity of some massive bodies and you say it's the gravity. So this is, this could be explained as the values of the outside of the elevator, independently of the theory use and as I asked this explanation which is formulated within the elevator would still be correct in one of these cases. Of course, but I thought the explanation just applied to the inside observer this is why the chest is a back and the observer inside cannot see the outside. Yes, so the inside is what prompts Einstein's explanation and the outside is what adjudicates between the two options, but both options are possible outside so the explanation which was formulated inside is not ruled out just because we go outside. It can be ruled out occasionally in the cases where the elevator is really accelerated, which you can see from the outside, but it's not ruled out in principle because you have these other gravitational cases with some massive budget present outside. But what is ruled out I thought that it was the notion of absolute acceleration that special relativity and Newtonian mechanics would give you and if you are the outside and you see that the elevator is accelerated because there is some mechanism say it's not an elevator it's a rocket and you see some fire going on from the back and then you see you say yeah it's still accelerated it's not like it's falling under the influence of their massive bodies but the notion is of absolute acceleration. Yeah maybe absolute is problem I don't know what you mean by absolute. Well absolute like absolute time, Newtonian absolute acceleration this is what Einstein was arguing for so at the end of the total experiment he said that the ghost of absolute motion and the absolute acceleration could be spelled out from physics something like this. Yeah but things like absolute, really absolute acceleration like absolute time and so they are not even, they are not even observable so that's not something you should be able to rule out by just looking outside of anything. Well Newton thought differently you know with the bucket of experiment. Yeah yeah maybe with the bucket but with I mean with just this special special template information supply to the whole universe. This is something which does not give any observable result. So these are the kinds of cases where I was you have absolute space in time or not really does not manifest itself in any way. Maybe the bucket case is different, yeah but this case if absolute, if absolute acceleration is thought in the same way as space in time in this examples of limits and clock there by then, then it is not something which you would establish by any observation. Okay. Yes, thank you very much. So if anyone has a short question we still have time. Otherwise we can also move to the second talk. If it was if you, if you, if, if by the end, if towards the end of the meeting you have a new questions to both our speakers so to have added you're still welcome to ask them. But for now, thank you very much for the interesting talk and discussion. And now we will move to our second speaker today, which is contemporary young. So Kanta, thank you for being here. You can say something. Can you hear me. We can hear and see you very well. So, sorry for being so early for you. Thank you for being able to join. The next speaker is he made a PhD with a joint direction from a person at the University of France and from Alexander and all for the company as it is. And now can turn has just finished a postdoc in Mexico, and he will begin as this autumn and as a postdoc, which is also a prestigious my career. Thank you for the postdoc at the National at the Computing University of Madrid. So, now, try to share your screen. This is about proposing a kind of pragmatist methodology for advancing metaphysical debates. So the idea that there are various formulations of quantum mechanics. And there are various philosophical interpretations of quantum mechanics, and the aim of the article is to establish relations between the two between what I call interpret interpretive stance so it will be a bit more global than full blown interpretation but between interpretive stance and formulations and model building choices. And the more precise methodology is to connect to in to connect different types of modalities, in particular natural epistemic and conceptual modalities so possibilities to different roles that they could play that could play the sort of theoretical structure in model construction. And so by attributing different roles to this modality the idea that we could interpret the theory the structure in in model terms. So I will explain how this work and I will then I will examine examine two formulations of quantum mechanics, the standard wave function formulation and the consistent histories formulation. And I will associate them with two philosophical stances interpretive stances the object, what I call the objectivist and the perspective of stance. So first, let me present some general considerations about the framework about model building scientific representative representation and so on so. It's very unusual to consider theories as organized collections of models. I take a model to be a mathematical trigger, at least in physics a mathematical structure. For example, a state space with dynamical constraints and boundary and initial conditions. This is mapped to a theoretical vocabulary so basically part of the structure on have labels which correspond to measurable quantities or dynamical parameters. And models can be used by scientists to represent concrete or fictional systems. For example, if we want to represent a fluid, we'll have to use a model that uses Navier-Stokes equations. And then taking the structures of the interpret the model that is taking structures part of the model to denote relevant aspects of the model. And with this in place, we can use the model to make inferences about the target. So now, this is the general, well, the general presentation of what I take to be a model and what representation I take to be representation of concrete systems. Let's talk about modalities. So, first, we can note that the models of a theory are sometimes interpreted as a model structure. So the idea that each model represents a possible world allowed by the theory. And then some philosophers have this interpretation and then they say that theoretical laws, which are the statements that are true in all models correspond to nomological necessity, what is true in all the possible worlds allowed by the theory. So assuming the theory is true it would correspond to nomological necessity. I have a, I want to defend a different approach, which I think is more neutral. Because for three reasons. First, because models can be organized in families corresponding to various types of systems. So we have in general, we have a kind of hierarchy rather than a flat set of flat collection of models, then models generally represent bounded systems in particular context, and not the universe as a whole so it's an idealization to think that a model would represent a full universe, a full world, generally they use to represent a system with a particular, particular environmental constraints. And then third models are relatively autonomous from theories that generally they incorporate a doc assumption that are domain specific. So the two reasons are a bit related but the conclusion is that I think from a pragmatic point of view we should rather conceive of models as conceivable applications of the theory. So it's the conceptual modality. Each model is conceptually possible in the sense that it respects the concept of the theory, the laws and the so it's so and then given a specific target system and a specific purpose. I would say that a subset of all the models of the theory are relevant to represent the system for this purpose. And hopefully that they are accurate. So here we have a practical and epistemic motility the idea that we have empirical inputs about the target we know things about what we want to represent. So here we have the practical inputs we are interested in some properties and not others so some idealizations are acceptable for example. And then. So this allows us to build a model that is relevant. And that represents an epistemic possibility for what the, what the target is like. Okay, possibly we could have a more than one model, we could have some cases we could have a probabilistic moderation of waiting of different possible models for example if there is uncertainty on a model parameter. We could reconstruct this as the idea that we have several models, each with its own value for the parameter and that we don't, we're not sure which model is accurate to is the good, the right model to represent the target and then we have a probability distribution on on the possible models. So this is the idea of having models as epistemic possibilities. But then to continue with the topic of mobility we can also see that models often have an internal model structure. So in particular probabilistic models represent alternative possibilities for a given system, for example possible outcomes for the system. And this is what allows for causal reasoning for explanatory reasoning for counterfactual reason. If we didn't allow models to have this internal structure we could not account for this kind of inferences where we do counterfactual reason. And so, so this means that there are two distinct levels of mobility in representation. You have the one I mentioned before which is that each model is a possible means of representing a given target. And that only some of them are relevant or accurate representation so we have conceptual and epistemic possibilities. So we have a model from one model. And then we have the modality that are inside the models, a model represent various possibilities, for example, that possible measurement outcomes. And only some, and only some of them are relaxed so yes and this, well the, the more intuitive interpretation the more natural interpretation is in terms of natural possibilities. So this is possible, naturally possible for this target system, given natural constraints on phenomena and so on. Here is a summary of the of this idea so you have the older models of the theory, which are grouped into families which are relevant for possible applications. So, so which model is an epistemic possibility to represent the target system and then you have possibilities within models which are possibilities for the target system. So for example an electron in a magnetic fields must be represented by a model of a given family, which are the models that are relevant, and then can be uncertainty on the exact value for the strength of the magnetic fields, the question of accuracy of epistemic possibility and the, okay so there's something. Okay the bottom is missing the resulting when assigned probabilities to various possible trajectories and these are more naturally interpreted as natural possibilities. So if we accept this picture, we have a kind of criteria for deciding if a structure aesthetic structure correspond a structure of possibilities, if it correspond to epistemic conceptual or natural possibilities. The idea that some components are fixed within models, for example the value of the magnetic field. And these correspond to conditions of relevance or of accuracy, which mean that they correspond to epistemic or conceptual, what we could call mind dependent modalities. The idea that each model has a value and we might be uncertain about the right value but the value is fixed within the model. Because it's so it's a mind independent modality. And then other components are variable, such as possible outcomes and the correspond to natural contingencies represented possibilities which are relative to the fixed elements. So a few notes about this approach. So the idea is to associate fixed components, the components that are fixed within models with epistemic modalities and the components that are variables with natural modalities. Now, I don't take this association to be too strict, I think there's flexibility in the way we can use model to make inferences. And my approach is partly normative. So, the idea that represented when possibilities are represented within model, they naturally induce an interpretation in terms of natural modalities because typically the users of the model will make counterfactual inference and talk as if they were talking about real possibilities. So this requires specific qualifications to to defeat this natural interpretation, we should say, okay, here are represent possibilities but they're not natural possibilities and so on so but the natural interpretation is in terms of So it's partly a normative claim that it's so for this reason it's better to follow this norm for philosophical analysis. Having to say that I will show that it corresponds to how models are generally interpreted in science and philosophy. Then, another remark is that accepting this, this is not a metaphysical, this is a semantic issue that I'm proposing it's not a metaphysical issue, and in particular does not commit us to natural modalities. It only implies that a model skeptic should use models without internal possibilities, some someone who think that there are no possibilities in the world a human for example, well, he could decompose his, if a model as an internal structure, he could in principle, he or she could in principle decompose the model into more final structures and and say that these final structures are the real model, other real representations of what exists in the world, and that their combination in and their probabilistic waiting is just a degree of uncertainty or a degree of presence but which model actually represents the world. And this would be a more natural way of doing of doing or presenting things for philosophical analysis. So, yes, the point is that it doesn't commit us to natural possibility this way, this way of thinking. So now, the question is, is there a unique way of classifying the components of a theory into fixed and variable categories. So among all the components that are used to build models such as initial conditions are dynamical parameters and so on. Are they, can we say whether they are fixed or variables within model is it's always the same and then can we give this interpretation. Well, first it can depend on the level of abstraction of the model or on the activity. For example, if you want to make predictions. It's plausible that a scientist who want to make precision prediction will feel his mother with all the available information. A scientific who want to explain a phenomena might keep initial conditions variables in order to do counterfactual reasons because explanations often work with a counterfactual reason. So this would mean that there is not an objective fact of the matter to whether a structure should be interpreted as natural as natural model is he or a piston model. However, there might be a privilege level of attraction that's something that is defended by Gary who say that there is a hierarchy of models, which are more or less abstract and when you go down the year. In the hierarchy you make things more precise by filling in values and so on, but Gary say that there is a privilege level of abstractions. And he bases claim on cognitive cognitive science. And on research about concepts. So I think it makes sense to to ask to claim that there is this basic level of abstraction and that when we make prediction we're just using a model that has this privilege level of abstraction. And we use initial conditions to make inferences so it's a different level we use the model which is which at this privilege level, which might, for example, have several possible initial conditions. But we take an input to make inferences. Anyway, I would argue that even if we accept that there is some latency over how to build models. And I will take the case of quantum mechanics about which components are fixed within models of variables and that is deeply affects the structure of the models and their organization in the theory. And it corresponds to different interpretive stances towards the same theory. So I will take the case of quantum of non relativistic quantum mechanics. We can consider the following ingredients that are necessary to derive predictions. We need to use the typical interpretation on the table so we need an Hilbert space and an algebra of observables, or maybe a configuration space. But we take the case of the Hilbert space. And generally this is interpreted as corresponding is this map to certain type of systems with certain degrees of freedom. To give the dynamics of the system, which is could be interpreted as a certain physical configuration. And then we need to specify observables to make predictions, which are generally associated with measuring apparatus in a in a concrete experimental context. And then we need initial conditions that can take the form of density matrix or vector. And generally this is interpreted or mapped to a preparation procedural to the first measurement outcome. So all these ingredients of model buildings could be model in the sense that we could choose one algebra of observable or another. So there is a set of possibilities there is choice to make, we can choose one Hamiltonian or another we can choose one value for the some parameters of the Hamiltonians. Another we can choose one observables and or another to make predictions and so on. These are model structures, basically. And the question is then is which ingredients are fixed. So which correspond to the epistemic or conceptual modality, and which ingredients are viable, which correspond to the represented possibilities. So the Hilbert space and the algebra of observables are fixed, because they are necessary to build a model you cannot do anything with that. And it's about it's a matter of identifying the type of target it's not a matter of conceiving of possible ways the target couldn't be. And I think it makes sense to claim that the Hamiltonian is fixed as well, because without dynamical constraints, whether content of the model is not informative. There's not much to say, except in the case of static systems, but then it's as if they had an implicit time. And again, it's because it seems to be that the Hamiltonian is about identifying the system and not about representing a possibility for the identified system. And then there remain latency of observables and initial conditions. The question being should be, should they be part should be fixed within each model. Should each model incorporate an observable or initial conditions, or should they be variables. And this is where the objectivist and the perspective stance come into the picture. The objective stance can is the idea that the initial conditions of the system are fixed in a given model. So remember fixed can mean that we can have epistemic uncertainty about what the initial conditions are so we can, but this should be interpreted as a probabilistic waiting of possible models, but each possible model has fixed initial conditions. The idea is that they are about that, where the system has isn't an isn't an initial state, maybe we don't know which but it is an issue in its part of its identity somehow. So it should be represented within models. The observables could be considered as mere contingencies because this specific system could be measured in several possible ways. And it's a contingent matter doesn't have to do with with the identity of the system, it's possible ways the system could be measured. So this view this perspective this stance. Then it seemed that the model represents an observer independent objects that can be observed or measured in various ways. And it can be associated with an intuitive idea that that we often find in philosophy of science that perspective independence is a guide to ontology this kind of the idea that variation what remains. So when we change observables in this case, when we change what is measured there's something that remains a constant and it would be a guide to what exists, what really exists. Okay, I will first change the order of my slide I will now present the perspective stance, which will be the idea that observables are fixed in a model. So it means that if we different observables correspond to different targets or different contexts, different things being represented, but initial conditions are contingencies. There are natural contingencies there are what possibilities for the same system the same target system. So if we add up this stance, it seems that a model no more represents an object that exists autonomously but rather a perspective on the world associated with something being measured. And that can this perspective can give rise to various out possible outcomes, and also possible initial conditions and all are represented as natural possibilities. So it's an intuitive idea that we have a functional mode, some kind that maps initial conditions and outcomes possible initial conditions possible outcomes. And that the object is no more identified by its intrinsic properties such as its initial state but rather relative to the observer, or to the environment that measures the system. Now, this two senses so correspond to different choices of what should be fixed in models and what should be variable, and I will show that it corresponds exactly to do two formulations of quantum mechanics. The first one is the standard textbook formulation. And the second one is a consistent histories approach. And, furthermore, the way these formulations are generally interpreted in the literature confirms the my approach and the idea of associating a variable parts with natural modalities and fixed parts with epistemic modalities, because precisely because the consistent histories formulation is generally interpreted as a perspective in terms of perspectives. And whereas the standard text with formation is generally interpreted in terms of objective states existing the word. So, you have around the table. Okay. So, not just to explain a bit in the standard textbooks, quantum mechanics, non relativistic quantum mechanics model is built by applying a law of evolution, using an Hamiltonian, applying them into Schrodinger's equation to an initial state. In the initial state we apply the law of evolution. And then we have a state for the system at any possible in a given time, which evolves continuously in time. Then measurement outcomes for given observable are determined probabilistically by the way function. So what we have here that initial conditions are fixed, because we need them to derive the whole way function, and all possible observable observables are compatible with the same way functions. So what is measured on the system correspond to external contingencies, and what naturally comes out of this stance, so then, what is interesting is that by adopting standard natural ontological choices that come out. In this case, we have a natural ontology of states evolving with time, according to deterministic close so the, this is because we need a state at every instant in time because we don't know when the system will be measured because precisely because measurements observables are contingencies. And this correspond to the objective stance. Then the consistent history approach. So, what is the idea. History is a sequence of projectors in Hilbert space. Roughly speaking, it correspond to an event instantiating a property for the system at a given at a precise time. And it's possibly a cost brains property doesn't need to be a perfectly fine grained property. So the set of possible history, and the framework, what, what is called a framework is a set of possible histories for the system. So, the idea that before building a model we should consider a set of possible histories. And this set must respect these conditions or histories must be orthogonal. Yeah, it's a tensor product of products to be to go with any technicalities and all this distance of products may be orthogonal which roughly means that the histories are mutually exclusive. But there's some to unity which mean that's at least exactly one of them must be realized by the system. And furthermore they satisfy consistency conditions, which depends on the dynamics of the system of the Hamiltonian. And this consistency conditions are an important aspect of the consistent history framework, they, they ensure that the normal probabilities, probability calculus can be applied so this is the way of avoiding all the weirdness of quantum mechanics. Framework, which it's, it's, it can be associated with the notion of the coherence. Well, the consistent histories approach was actually will play an important part for the development of the notion of the coherence in quantum mechanics which is now central in quantum mechanics. And so it's associated with this consistency conditions. So the framework is what we need to build a model. We need to specify what history, among the sets of mutually exclusive histories. No, we need to specify a set of mutually exclusive histories, that's something you need. And then we can build a model using the Hamiltonian. Yeah, it's on the slide after so given the framework and the Hamiltonian of the system we can compute conditional probabilities between any two projectors or any two events of the of the framework. So it's similar to transition probabilities in the, it's very similar to the path integral formulation. So it's kind of transition probabilities between events. And given that the framework satisfies the consistency conditions, we are sure that the model will respect standard probability calculates. And roughly the model could be analyzed as a kind of causal network between events if we, if we have a counterfactual theory of causation for example it's can straightforwardly be analyzed as a causal network of events. And, okay, and so just to go back to the slide before we have the one framework for which is important is the idea that when we do counterfactual reasoning, we should do this within the framework we cannot do that with outside between we can not switch framework so otherwise we will get logical inconsistencies. So the idea that changing the framework is changing the model is changing what we're talking about change the target system. Now, we can see that this is exactly what I call the perspective stance observables are fixed in the model because they currently giving a set of histories. So changing the framework is roughly equivalent to giving a, a finite set of observables at, at distinct times. And the initial state is not given. So the model the final model of a constant history does not give us probabilities for history. For this we need another input such as initial conditions but they're not given in the model. All we have is transition probabilities between events but we don't have a specification of which initial event is more probable than the other. So the initial state is not given it's contingent. And this corresponds to the consistent history is formulation. And what is what is interesting that we get a completely different ontology out of this like naturally we get an ontology of possible events and causal network. So here's a summary the so the objective stance observables are variable initial conditions are fixed, and we get an ontology of states and evolution laws, and the identity of systems is intrinsic. Observables are fixed initial positions are viable and we get an ontology of events, and the causal relations and the identity is relational identity of the system is relational because it's relative to what is measured on the system so sweet. Okay, and then it's in this seems to correspond to the way. This formulation of quantum mechanicals interpreted so generally. So Griffiths who proposed the consistent histories approach is a physicist who first proposed this approach. He assumed the prospectivist stance so he says that the choice of framework is a matter of adopting a perspective on system and so on he also say that initial conditions and outcomes are contingencies and natural contingencies. And that corresponds exactly to what the approach I propose would predict. And then scientific really is typically use the standard way function formulation, and they, they think of the way function representing objective states for systems. There is even a theorem that that prove that the way function cannot be interpreted as an epistemic entity. And one, maybe one notable exception seems to be the Copenhagen interpretation of quantum mechanics because it's just, it's expressed in the standard textbook formulation the way function formulation. But it's not very realistic as instrumentalist flavors. However, even in this interpretation talk talk of evolving states is pervasive. Furthermore this formulation seems incomplete. Because the notion of measurement is left and analyzed. I think Griffiths say that the consistent history is nothing but Copenhagen don't write. So, the idea that if really want to accept the Copenhagen interpretation you should put the observables in the framework so that you should use them to build your model. So, this seems to vindicate the approach, the methodology I am adopting. And I think just to finish to conclude I think that an interest of this methodology of associating interpretive stances with formulations with model choices. And that maybe we could assess the different interpretive stances on the basis of the fruitfulness of their of the models that are built using these stances so it gives us, it might give us tools to assess pragmatic to assess pragmatically which interpretive stances works better. I don't know if I have time to present this. Not very much. Okay, we have 15. One minute. Sorry, one minute. Okay, I will. Well, so basically why we just say about, we just put the last slide then. Well, just rapidly. So, I think that the way the standard way function formation has a lot of problems. So, as is well known, the bone rule is external to the model so it's data season clear. Well, there's no locality problem and so on. There is no straightforward ontology so you have a lot of programs of completing the, the theory with primitive ontologies. And you have problems of causality causation so the relation with high level theories is unclear. The consistent history is a way of avoiding all these problems. So basically the bone rule is built into the model so you status is clear, probability that we behave. The causal network is local, it's perfectly local correlations are always explained by common causes. And the ontology comes out quite naturally and it's directly associated with our measurements so there is interpretation is straightforward. So, in my opinion, the scope is only the relativity to a framework, which is a weird object, but I want to discard this because it can, it will lead us too far. But I think that one way to assess these two stances be beyond what I've just said is to examine the virtues, the virtues of the models produced. Well, explanatory powers generally considered an important aim for science. And it's often analyzed in counterfactual terms, so giving an explanation is giving, for example, or causal terms, giving an explanation saying, well, if this would not have happened, etc. And it's also often recognized that explanations are contextual there is a sensitive to properties of interest so for example we can explain a car accident either by referring to the, to a problem in the, in the engine or to, to the architecture the urban architecture of the road and all explanations are valid depending on what we're interested in. Whether it's a driver or whatever. So, and all this makes more sense. If we fix observables, observables corresponding to the properties of interest and if we let initial conditions vary for explanatory purpose. So it seems, I would say that the models of consistent histories are more directly explanatory. They fit better with explanations in science in general. This is the example of the explanation of the spectrum from the boss model of the atom. Well, in general the observable is implicitly fixed and there is an implicit application of bone rule, because we're interested in emitted frequencies so we're interested in one observable energy with not interesting position, the position of the electron in the spectrum. And, but the initial state of the atom is not fixed. Because it must vary. If we want to account for all possible spectral rights. And of course, in general the explanation given classes is based on way functions. So this, I would say that maybe this is because what I saw remarks as I gave before that there is kind of flexibility anyway in the in the use of models so we can do counterfactual reasoning on initial states even if they are not fixed models so the association I propose is not, it's not strict because in any case, models are rather flexible it's more like it has a normative components, the best the best way to present the models should follow the more natural interpretation of the model. So, in this case I would say is that for explanatory purpose, we should, maybe to know that if they we should. We should use consistent systems. And here it is. So basically the general idea was to make associations between modeling choices. Interpretive stances to other theories by using the role modality to play in the model structure play model construction. And this gives us two main stances objectivist and prospective stance. Thank you for your attention. For every interesting talk. We are happy to have heard it, and we still have some time for questions. So, I see people applauding but please also I see you happy if you have any question. In the meantime, maybe I can ask one lady. And how do you have anything to say about other interpretations of quantum mechanics, and do you have anything to say about. Sorry, so you, you have talked about ordinary quantum mechanics and about the consistent histories approach, but of course there are also other interpretations of quantum mechanics like. Whatever. So do you have anything to say about this interpretation. And also, there is a high center picture of quantum mechanics of which I'm not a specialist, but it looks like they are observables evolve and wave functions stay fixed while in the quantum mechanics wave actions evolve and observe what they fix. So do you have anything to say about this high center picture. Okay, so. So basically, the article was more frame like, like the proposal of a methodology, rather than. So, the idea was to to to to apply this methodology to a few cases and of course it would be nice to extend it to to other interpretations as a formulations, but I didn't do that. So if you're interested in the article there are a few notes on the mechanics, a few, a few footnotes. Because bombing mechanics fixes the positions of it's it's like it's as if a preferred observable was fixed at the theory level. Not even at the level of models but even at the theory level the position measurements. This this wouldn't yet. So this would. I think it corresponds to it. There's a way of interpreting it with my approach. And for the Eisenberg picture I haven't thought about it. But it's, it's, it's an interesting question so I will think about it. And then analyze analysis and I couldn't do it like right now but it's interesting. Thank you. Is general. Would you say that. Would you say that there could be like middle cases between the two you are presented. Because you presented the extreme cases where as all observable suffix and all initial conditions are not all the other way around but in principles and we couldn't have been middle cases. Well, some reviewers, whether it's quite complex, some reviewers told me that in some theories in some models, the initial conditions are fixed, but the Hamiltonian of the system is not fixed. So it's more, it's a bit more complex that what I presented. Because in scattering theories. So you have this kind of models where boundary conditions and initial conditions in the far past are fixed, but the Hamiltonian remains a variable. So it's a bit more complicated and it would require more final analysis to a case by case basis. Okay, thank you for your advice. I have a question for you. Thanks. I thanks a lot for this great talk from the very interesting and inspiring, but I have a question for clarification. Could you show your slides again and go back to the next two lost slide I think the one of these three points there. You say so it makes more sense to fix observables and that initial conditions vary for explanatory purposes. I don't really see how that follows from the first and the second points. So could you just reformulate. Okay. So the idea that if we want to use a model, a scientific model to produce an explanation for some phenomena. And I think it would make more sense in the case of quantum mechanics to fix the observables in the model, because when we provide an explanation in general we're interested in particular properties. We don't need to keep the observable variable. So the, the example I gave at the explanation of spectrum of the emission absorption spectrum of atoms from the model of atoms. So the roughly the explanation is that electrons can go from one energy state to another and when they do so they emit, they meet photons chorus and the frequency of photons correspond to the difference in energy states. So you have a model with all the possible energy states and the transitions between energy states produce spectral rays. In this case the observable is fixed is implicitly fixed by the for the explanatory purpose we're interested in in the energy in the energy state of the electron and not at all in its position. And, but for the another another aspect. So this is a sensitivity. This is a second point sensitivity of interest. The first point is that in general, when explanations are often analyzing counterfactual terms. So and counter the counterfactual generally works on something that is similar to initial conditions. So if I want to say to explain the fire, I will say there was a spark, if there hadn't been this part there wouldn't be a fire. And so I have like a counterfactual on initial conditions a spark a spark or no spark, which produce fire or no fire. And, and so it makes more sense if we want to use a model to explain makes more sense to have all the possible initial conditions represented within the model. I see it better now, but the woodwork aspect is just that it's counterfactual or also the interventionist aspect of it. And I still don't see why the causal body word causal terms is there. Well, you can just keep counterfactual if you want causal is just, it's just that it's just that the models of consistent histories can be interpreted I think they can be naturally interpreted as being causal. If not for the perspective aspect which clashes with the usual ways of considering of causality but it's like, it's like a well behaved probabilistic structure of transitions of local and it's local and so on so it's quite easy to have a counterfactual analysis of causation in this case. But, and then some people say that explanations are causal that explaining something is giving a cause for phenomena so again it would be, it would make sense. Okay, thank you. Okay, thank you for this discussion. Now we have to finish. Thanks to both our speakers. Thanks to all the persons who are in the public and the special so just missing you.