Sorry for abandoning the conversation, was suddenly quite busy for a while.
Thank you for the explanation, that’s very interesting. I have heard about many of those concepts before but not described using the term ontology. Relational ontology specifically seems to be a bit more systematic and probably contains some further insight than my vague notion of “the past is a different country”. Maybe I will look into it. Back in the day, one of the four subjects I thought about studying in Uni was history, which is of course its own thing, but strongly tied to the question of how to view and understand the past as well.
As a physicist, I am perfectly happy to admit that most systems studied in other subjects are more complex. In fact, one might say that’s the point of physics - it is an attempt to find the simplest possible models describing specific aspects of the natural world. Traditionally this has taken the form of a reductionist project in which phenomena are analyzed and split into constituent parts which can be individually understood, hopefully leading to the discovery of universal laws. Once the individual parts are understood an attempt to reconstruct more complicated phenomena from these “simple” theories is made. Because the basic constituents are isolated and simple the level of description can be much more thorough than for a more complex system. This is why physics seems very complex, with lots of complicated mathematics, in some sense, it is only possible to have such a complex (seemingly correct!) mathematical description because the underlying system is so simple. Going back to some of the stuff I touched upon in my initial post, an important concept in physics is emergence and universality. It can be shown that many-body systems will have various emergent properties due to interactions between particles that cannot be understood by analyzing each particle individually. Crucially one can still use the underlying simple microscopic theory to derive these emergent properties (for cases we can actually solve, large many-body systems quickly become intractable). Some of these emergent macroscopic properties display universality in the sense that the details of the microscopic model are unimportant. We also see that there are certain structures that seem to be universal across multiple energy-scales, despite having different microscopic constituents.
So even in physics more is different and the reductionist program can only go so far. Although, as good physicists, we of course attempt to bridge the gap between the two as best we can. It’s always satisfying to explain a complex emergent phenomenon in terms of a microscopic model. However, for very complex systems, such as biology, societies, and economics finding microscopic models that correspond to the macroscopic phenomena might be a fool’s errand due to the sheer complexity. Of course, any attempt at this would have to define the relevant degrees of freedom which in this case is decidedly not atoms or quantum mechanics. When physicists describe an atom they don’t really care about what’s inside the neutrons and protons (quarks) for example, because it is irrelevant at the considered energy scale.
Of course, the analogy only goes so far, I’m not a proponent of the mathematization of social science in general and I think there have been some embarrassing examples of physics imperialism in some past attempts. That is not to say that I don’t think mathematics can ever be a useful tool, just that one has to be very careful about its application. I think that economics in particular as a field has suffered from the illusion that having a nice mathematical framework makes models more “true”. It is of course nice to have a useful mathematical framework, but it doesn’t inherently tell you anything about the correctness of your model. I still think mathematics has a very important role to play in economics and in the last few years I have become somewhat interested in the subject of ecological economics which is an attempt at rethinking economics as a subsystem of the ecosystem rather than as its own isolated thing. In biology, mathematical theories have made some really cool strides in the last couple of decades, but similarly, I think that one has to be rather careful with the application.
The world of quantum research is relatively small I guess, Christopher Fuchs came here for a conference once. He gave a pretty entertaining talk going through some various interpretations of quantum mechanics (a bullshit of interpretations as he deemed the appropriate phrase for a multitude in that context). He also talked about some “real” physics and quantum computation, I talked with him at dinner, he seemed like a pretty cool guy.
For other people, as I alluded to above I think it is fair to say that many working physicists are somewhat skeptical about the utility of quantum foundations. It is seen as speculative and usually more of a philosophical debate about interpretation than a physical debate as these interpretations don’t generally have different experimental predictions, since they are all trying to interpret the same basic mathematical theory which we know gives very accurate predictions. At the same time, some people think we have moved forward somewhat in our understanding, with emerging fields such as quantum information giving some surprisingly simple insights that hadn’t been thought of previously. However, the argument tends to be that these insights were due to people working on concrete problems and experimental progress that has allowed us to probe and control isolated quantum systems in ways that were not possible in the past, not from people arguing over interpretations.
So discussions of topics like the measurement problem usually happen after a few beers at the conference dinner, not as the main topic of scientific discussion. Of course, there are exceptions, but it is usually well-established people and I think there is a sense of “They paid their dues and have done real physics, so now they are allowed to speculate”. Maybe we need an anthropologist to study the scientific community. :p
@yeso I think this might also somewhat answer your question. Most physicists don’t consider that QM has fundamentally made the world less objective. In fact, one very quick way to make most quantum physicists very annoyed is by suggesting that quantum mechanics is some magical, mysterious thing (it is a very precise theory that makes very accurate predictions). Even using QM to lend support to idealist interpretations of the world is somewhat frowned upon, perhaps because of the association with the former in many people’s minds.
I would like to expand slightly on the realism vs instrumentalism distinction I mentioned in my last post as it relates to your question of whether or not we could simply build a huge microscope. Because the thing is, on some level we already have. Nowadays there are multiple experiments in which we can image individual atoms. However, the problem is that any such microscope is extremely theory-laden (and always will be, by necessity). What this means is that in order to get the data, i.e. the image, there is a whole set of physical theories that are required to be correct. In fact, one could go so far as to say that there is no such thing as pure data/measurements in the absence of a theoretical framework in which to understand them. When we measure anything it always relies on some physical theory for understanding the measurement. For simple things such as measuring a macroscopic mass, the required theories are much less complex, but for difficult measurements, such as imaging very small objects more theory is required. Of course, one generally relies on very well-established theory which has been shown to work in many different contexts, but nontheless our measurements are part of a complex set of theories. Luckily we mostly find that once a theory has been well-established and is consistent with data in one area, it is also consistent with other applications and the data obtained in that area.
In the realist view the specific objects of the theory, say electrons, neutrons, protons, etc. (or certain gauge fields and symmetries if one is more fancy like @compositehiggs mentioned) are real elements of nature, while an instrumentalist would say that it doesn’t matter, these objects are simply theoretical constituents that make up a theory which is consistent with the maximum number of “experimental data” and therefore “true” in the sense that it makes good predictions. Historically certain objects that were thought to be “real” (such as caloric) are now thought of as constituents of a wrong theory and therefore not real. However, it gave correct predictions within certain limitations and in the instrumentalist view, it was therefore a perfectly good theory until a better one came along. In the same way, we might find a better theory in the future where the objects are different from those of the current theory. Instrumentalism is therefore rather flexible, but it has the obvious disadvantage that taken to its logical conclusion it gives up any pretense of real explanatory power, as any theory which is consistent with data is fine. This is why I think most physicists fall somewhere in the middle, often giving the impression of being realists, but reverting to a more instrumentalist position when pushed. One important thing to note is that instrumentalists don’t claim that there is no external world, there is definitely something out there that provides us with “data” when we interact with it, its just that they aren’t married to the reality of any given particular model.
Very briefly, because I am going to bed. When people talk about a GUT what they generally mean is unifying the electromagnetic, weak, and strong forces at large energies such that they are all aspects of one fundamental symmetry group. What exactly this means is slightly complicated to explain and I will not attempt it now (it is also completely unrelated to my field of research in quantum mechanics). It doesn’t have any particular relation to determinism though.