Physics is a model of the way the universe works. There's no reason to be sure that it does work the way that we model it. Practically speaking though it doesn't really matter as long as the model gives us accurate predictions. At that point you are entering the realm of philosophy.
A model can become a cage. Although the QM "infinite trajectories" interpretation is fine at explaining what happens in a quantum system from the perspective of an observer. But it doesn't provide any intuition about how the systems really behave. There may be ways to get access to more realistic interpretations. If we had them they might help us work with quantum systems.
That's a fascinating philosophical presupposition you have there: That there is such a thing as a difference between the observable* behavior of a system and its real* behavior. I won't agree or disagree with you. Just pointing it out because it's really interesting to me.
*You used essentially those words ('observer', 'really'). I won't try to pin you down into a particular definition of them, but I'm guessing we at least approximately agree on what they mean.
You could make a similar but less controversial statement by substituting "low-fidelity observer" & "high-fidelity observer" for "observer" & "reality". I wonder if that's what you mean, or if you meant what you said?
Hm... I suppose this could be mathematically/logically equivalent, but the thing that bugs me in GP's answer (and the way I hear QM talked about in general) is the very concept of an observer. I've never heard a good explanation of why an observer would be a thing - I'm not sure if there could be, without creating some kind of magical realm for it to live in, detached from the rest of physics.
What "an observer" really means, in the context of QM, is a large, approximately classical system interacting weakly with the system being "observed" (such that the interaction can be modeled perturbatively). Humans "observe" photons, but so does a pail of water.
It's a way of framing certain classes of problems, not a distinct sort of entity.
We, humans, are limited in our understanding of the worlds by what we can perceive and conceive. What does it means to understand how a system really behave when we are so limited? That’s an interesting metaphysical question but we have left the realm of sciences by asking it. Sciences care about what can be experienced.
The aim of sciences is to accurately predict the results of experiments. A model doesn’t have to be simple or intuitive, just accurate.
Obviously everyone would like a simpler model predicting the same things but not because it would be more real, just because simpler is nicer.
Feynman's QED talks pretty extensively about this as well. An intuitive mental model that humans can picture in their heads is a nice to have, not a requirement. Understanding how a system "really works" is also not really a goal of physics - the science is about predicting physical phenomena - and we generally choose whatever is the simplest equation we have currently available that does that. If you want to define the bar for explaining how a "system really works" as being able to give you an intuitive human-centric mental model you can fully understand and capture in your head - well, you are moving the goal posts over what physics really is and quantum physics has already left you far behind.
> Understanding how a system "really works" is also not really a goal of physics - the science is about predicting physical phenomena
I have to point out the above is a rather strong and debatable claim. I think most people who study science do want to understand how things really work.
Even if we accept that physicists only want to predict phenomena as opposed to understanding them, the same can't be said of other sciences (let's say astronomy, or molecular genetics). Mathematicians seek almost exclusively to understand things rather than predict them. So the claim attributes a certain lack of curiosity specifically to physicists, that doesn't apply to biologists, mathematicians, etc. To me, that makes it even more peculiar. So I'm skeptical.
I put "really works" in quotes because the definition of how to get to the bottom of how something "really works" is up for debate itself. The original context for claiming something like path integrals can't be how the system "really works" because it is some combination of being too complex, lacking an intuitive mental model for how to conceptualize it, and invoking things that seem extraneous to the person making the claim (possible paths that aren't necessarily realized).
I would agree that physicists have the same, or perhaps even more, curiosity regarding discovery as other fields (partly why they are drawn to understanding the nature of the existence/universe itself) - but there is certainly an error with this narrow definition of "this can't be how it really works because X" is simply wrong - we choose the simplest explanation which meets the scientific criteria for the time, and up until something new is discovered - that is de facto how the system "really works".
Ultimately people have this assumption from classical mechanics that everything can neatly fit into intuitive thought experiments to understand the nature of reality, but quantum mechanics has not followed the same human-centric intuitive modeling. Does it mean we haven't figured out how the system "really works"? Ultimately, it's a philosophical question, not question directly related to physics which is showing the way through predictable repeatable science.
The path integral formulation doesn't sound that counterintuitive to me, though I don't know anything about it in terms of actually computing with it. Aren't there similar integrals in statistical thermodynamics, where what is "really going on" is random motion of molecules and the math has to consider every possible path, though in Euclidean space? I'd like to understand this stuff better someday. The "really going on" of quantum mechanics is perhaps more mysterious, but that doesn't mean physicists don't want to find it.
You mean you don't understand when you don't know something? If you had no problem reasoning about quantum physics, you wouldn't say it's a philosophical question.
My post is not a statement about animal sentience. Until we can have a discussion about empiricism with another kind of sentience, I think beginning sentences with "we, humans" will be fine. I would appreciate if you could go farm PC points somewhere else than in reply to my comments and kept condescending winks out of it.
Unless you are making a pun about AI bots and I’m just having a bad day, in which case, I will have to ask you to be kind enough to bear with my rudeness.
My comment was not motivated by any notion of politics. Notice I didn't say "organism", but something far more general. A galaxy is a subjective agent in the sense that experiences incident upon it are subjective in nature (localized in time and space vs its environment, subject to some notion of "interpretation", broadly defined, on the part of the receiver).
Besides, there is nothing about a public-facing forum that prohibits anyone commenting on your posts for whatever reason. Since you brought politics into this, I will just say we live in a society and you have to accept that if you are to avoid such unhealthy and reactionary outbursts in the future.
There is no politic in my post. You were literally trying to correct my use of language. My previous comment is a polite way to tell you it’s unwelcome.
> But it doesn't provide any intuition about how the systems really behave.
In physics, intuition is much more of a cage than the models.
In fact, I would argue that our intuition itself is such a model. It's just one that vertebrates evolved over 100s of millions of years that enabled their brains to optimize Darwinian fitness.
It has layers upon layers of simplifications and heuristics to reduce complexity to a levels it can use to compute viable behaviour.
Models answer the questions What? and How? They do not answer the question Why?
The simplest model explaining all observed behavior, and even better, making new predictions that are then confirmed, is the model we tend to call "reality." But it's just a model. When you step back to think about it - everything is a model: colors, sounds, the table you're sitting at, the chair you're sitting on. We've just become so accustomed to these models we think of them as "reality" and it's super convenient to do so. I think that's a big point the Buddha was trying to get across.
Such a "truest" formula doesn't really exist, or at least what you determine to be the truest is just a matter of definition and taste.
For any equation it's mathematically trivial to come up with a different set of equations that produce the same result, e.g. for example just via approximating the original function with some infinite series that is guaranteed to give back the original result in the limit.
But even beyond such trite examples, it's not unlikely that there will simply be multiple competing ways to model the same data that the equation takes in and spits out that are very different in form and function, and perhaps even in mathematically incompatible ways (this could happen if e.g. the equations model more than what exists in reality but all of reality is described by some subset of the parameters of these equations, like how gravity works for negative masses but such a thing does not exist from what we know).
You could then decide on some reasonable criteria which of all your models is the truest one, but the criteria themselves will be up for subjective debate.
