A bigger way to think about it is ... is the a universe like a movie where each still image lasts a Planck-time (or some other smaller chunk)? Is the entire state of the universe encoded in stasis for that instant, and then boom ... it's time for the next "Planck frame".
It's really hard to resolve that kind of universal time chunkiness with the ordinary time dilation effects that can be observed at relativistic energies. Whose frame of reference counts? We do know that space-time can be warped ... it's harder to imagine that this kind of warping and curving is discrete. That's one reason why many believe it's a smooth flow.
To say that time is "really" continuous under such circumstances seems like a weird philosophical claim.
And inversely, science is not just measuring -- that's the naive positivist (and later Popperian) view of what scientists do.
For example:
As Thomas Kuhn (1961) argues, scientific theories are usually accepted long before quantitative methods for testing them become available. The reliability of newly introduced measurement methods is typically tested against the predictions of the theory rather than the other way around. In Kuhn’s words, “The road from scientific law to scientific measurement can rarely be traveled in the reverse direction” (1961: 189). For example, Dalton’s Law, which states that the weights of elements in a chemical compound are related to each other in whole-number proportions, initially conflicted with some of the best known measurements of such proportions. It is only by assuming Dalton’s Law that subsequent experimental chemists were able to correct and improve their measurement techniques (1961: 173).
https://plato.stanford.edu/entries/measurement-science/#EpiM...
It's possible the Uncertainty Principle is wrong. One can come up with theories that it is wrong. And what sorts of observations might hypothetically observe or refute them. As far as I know, there is no serious science doubting HUP at present. (Which doesn't prove it's right, it's just the current state of things).
But simply speculating about what things might exist that current scientific understanding says scientific laws would prevent us from observing or measuring or seeing any effects of whatsoever -- is still not science. It's not that you can't have a scientific theory which current measurements seem to refute and still press for it (your Dalton's law example). It's that you can't have a scientific theory with no even theoretical way to refute or confirm it by observation. That's not a scientific theory.
Ok, enlighten me. I've read philosophical works where that certainly seemed to be the case. There's also this weird thing where only a specific lineage of schools of thought and certain ancient Western philosophers are "real philosophy" and others (e.g. anyone with a non-Anglo last name) are "not real philosophers". No True Scotsman at its finest.
>And inversely, science is not just measuring -- that's the naive positivist (and later Popperian) view of what scientists do.
In graduate school, I worked at a lab in Stanford (I didn't attend there, but was fortunate to have spent some time there). Your statement would certainly be news to the PI I worked for, who was a heavy Popperian. You can't falsify the existence of sub-Planck lengths or times, that's for sure. Science was absolutely nothing more than that to him. And while you can certainly claim an Appeal to Authority fallacy, Stanford, at least, considered my PI competent enough to award him a PhD in a scientific discipline, so I'm not sure how much I can agree with your post.
This is not to suggest that we should not inquire on these topics, but rather that they should fall under some other umbrella besides Science.
[0] Or whatever is left of it at this point.
It's that science itself as a process is not Popperian (and of course modern epistemology has moved from the times of Popper).
Actually what you say is the weird philosophical claim.
It's like saying Australia didn't really exist when we couldn't observe it (or see any effects from it reach us).
The thing is, to say it could be continuous even if that's not observable might be wrong. But not because it can't be both continuous and not observable: just because it can also be discreet and not observable, and we can't tell which of two it is for sure.
Whether we (or any observer imaginable) can observe effects or not, doesn't mean it's not one or the other.
This is a straw man, and I think you know that. It's more like saying Atlantis doesn't exist, and, well, to the best of our knowledge - it doesn't. I'd be happy to re-evaluate upon receiving evidence that Atlantis may have existed, just as QM physicists should be happy to re-evaluate when sub-Planck-scale phenomena can possibly be observed using a theory which is also consistent with the rest of our observations of the world.
Oh and an even better analogy than Atlantis - it's like someone saying Australia didn't really exist when we couldn't observe it, and claiming they would prove it by sailing from Chile to Africa without encountering any large land masses.
So no, he's not making any weird philosophical claim at all.
I don't see much difference. If you're "happy to re-evaluate" (e.g. open to the possibility) then the answer (even re: Atlantis") is "I don't know if it exists", not "doesn't exist".
More than that. It simply doesn't exist in any meaningful sense and it's a waste of time to even think about it.
What cannot be observed in principle has exactly zero impact on the universe. That's pretty much a definiton of "not existing".
The irony is it's actually a philosophy (a philosophy of science among several in particular) saying the above.
It's not anything scientifically observed itself that says that when something can't be measured "it simply doesn't exist in any meaningful sense and it's a waste of time to even think about it".
EDIT: looking at this "axiom" from another angle. Imagine that I claim that atoms are really built out of Zeta faces, that are exactly like quarks, but have smily faces etched on them. I also claim that it's in principle impossible to tell a difference between a Zeta face and a quark (hypothetical quark, after all it's all Zeta faces). They just are there. At this point you could correctly observe that since the universe would look precisely no different whether or not there are smiley faces on quarks - there's not a bit of information distinguishing these two hypotheses - my claim is absolutely meaningless and a waste of time. This generalizes to all kinds of invisible, unmeasurable magic faries under the bed, etc.
(It's probably a well-trodden philosophical ground, but I don't know who to read to find a decent discussion of it.)
There are several logical holes in the axiom.
The first big one is that it implies logic is applicable to the universe, i.e. that the universe must abide by logical necessities (and even more so, by logical necessities the way we perceive them). Setting aside the fact that we cannot prove logic's applicability logically (it's itself an axiom), QM has given us many non-classical-logic compliant observations.
Then, there's the assumption that: "it exists <=> something would be different about the world if it didn't exist". That's again an assumption. I could just as well consider that (the fact of its existence turning from false to true aside) the world could be the same whether something exists or not.
This presupposes when it should instead prove: that existence necessitates difference in the world.
Third, "it's in principle observable (though its impact) <=> can be studied by science" -- whether something can be studied by science or not shouldn't be a criterion for its existence.
Black holes existed for billions of years before they could be "studied by science", or before science even had any understanding of them. Only in retrospect we say that they "can be studied by science". Did the not exist when we couldn't say that, and exist now?
Or they did exist and we only lately came to find out about them, and that we can actually study them? If it's the latter, why wouldn't that -- the possibility of existence- be the case for tons of others things (e.g. sub-plank length stuff)? Because our current theories say so? Or because we thing our current theories are the be-all end-all we'll come up with?
Fourth, one could argue that something could still exist, have impact, and not be observable. E.g. if it's impossible to make it not exist, or look at that level (so that we have no way to measure its impact). E.g. some entities or energies at the sub-Plank scale level could hold the universe together and be essential substrate. But we just have no way to know about it, because we can't look at that level (and our theories can't even go at that level).
>At this point you could correctly observe that since the universe would look precisely no different whether or not there are smiley faces on quarks - there's not a bit of information distinguishing these two hypotheses - my claim is absolutely meaningless and a waste of time.
The claim would be a waste of time to try to verify.
It could still very well be ontologically true -- which is what we're discussing.
That something that can't be verified in any way doesn't exist is a logical jump. What we can say for certain is that it could or could not exist, but we can't verify it.
We can't even say that it has no impact to us, because without being able to verify it, how can we be sure it has no impact? At best we can say "it has no impact as far as we can tell".
But it could still have a huge impact -- the same way the Quarks you've mentioned have a huge impact, had a huge impact even before we knew existed and before we could measure them, and would have have a huge impact even if we remained forever at the 15th century level of physical knowledge.
> that the universe must abide by logical necessities (and even more so, by logical necessities the way we perceive them)
This axiom can be defined better, to account for the fact that we only perceive the universe through our minds, and this opens a whole can of philosophical worms - but in practice, this axiom does hold, and if it didn't, we could only pack our bags and go back to caves, as nothing would make sense and there would be no point to thinking.
(I didn't dig too deep in that can of worms, but I vaguely suspect the justification for such axiom could be found in anthropic reasoning.)
> QM has given us many non-classical-logic compliant observations.
Well, classical logic is pretty limited and it isn't be-all, end-all of logics, and not exactly what we use in daily reasoning anyway. I admit to not having much knowledge on the more complex types of logics, but the problems I recall seeing boil down to misapplying logic as an abstraction. For instance, I just stumbled upon the following example of "classical" vs. "resource-aware" logic:
"suppose you're standing at a vending machine that dispenses candy for a dollar and also dispenses coke for a dollar. You might write that as 1$⇒candy and 1$⇒coke. But then inferring that 1$⇒candy&coke is clearly wrong. The dollar gets "used up"."[0]. The post introduces resource-aware logic as a solution, but to me the problem seems to be modelling vending machines as (classical) logical implications; it's kind of dumb if you think about it.
(I'm also aware that probabilistic models are a better way to describe the observed world in practice than formal logic.)
> Then, there's the assumption that: "it exists <=> something would be different about the world if it didn't exist". That's again an assumption. I could just as well consider that (the fact of its existence turning from false to true aside) the world could be the same whether something exists or not.
I don't see how it could be any other way. Without asserting that there is a non-zero diff between universe with something and universe without something, "existence" is an empty label without meaning.
> This presupposes when it should instead prove: that existence necessitates difference in the world.
"Existence" is a term we define, and again, a different definition seems meaningless.
> whether something can be studied by science or not shouldn't be a criterion for its existence.
I didn't mean that current science defines what exists or not. I meant that existence of something has observable impact on universe. Observable in principle - not right now by us, but theoretically observable with sufficient knowledge and technology level. And if something is observable like this, then it falls into domain of science - it could be studied, and conclusions could be drawn. My point is that the set of things that exist is equal to the set of things that are of interest to science. This is not a time or technology-dependent claim.
> Fourth, one could argue that something could still exist, have impact, and not be observable.
How? "Have impact" is synonymous to "in principle observable".
> E.g. some entities or energies at the sub-Plank scale level could hold the universe together and be essential substrate. But we just have no way to know about it, because we can't look at that level (and our theories can't even go at that level).
I think you could only say such entities exist in a meaningful sense if their non-existence would make the universe look different. This way you could indirectly infer their existence through considering the things you've observed and not observed. If the sub-structure of the universe was completely screened away, so that whatever happens there, no bit of information reaches our universe, then I see no meaning in the question of whether or not that sub-structure, or entities inhabiting it, exists.
Again, by "observable" I at not point meant "observable by us, today". I meant "observable in principle".
--
Lemme try to answer those, as this is the core of the current disagreement I think.
Consider the case of parallel universes -- they are actively studied by scientists as a notion, and there's very much a question of whether they exist, while still "no bit of information reaches our universe" from them.
Does that preclude their existence, or makes such an inquiry into the possibility of their existence meaningless? Several physicists and cosmologists (even major ones) don't seem to think so.
And that Euclidean geometry itself is only one possible geometry, but took us several millennia (until e.g. Lobachevsky) to find out -- it was taken as a kind of axiom itself, like absolute time etc.
The cat before you observe is ... you never know. Observe change it.
Qm - I assume you mean wave functions and their collapse - are an explanatory mathematical abstraction, but they follow rules grounded in observational data. You don't say "wave function collapsed there, only it's impossible to measure it"; that's meaningless. We say that the wave function collapses when we find some observation changing from one state to another in a way that implies there were superpositions of state involved in the middle.
Does it mean that time does NOT progress in discrete chunks, or can not? I don't believe so.
Not sure
> It has since become clearer, however, that the uncertainty principle is inherent in the properties of all wave-like systems,[8] and that it arises in quantum mechanics simply due to the matter wave nature of all quantum objects. Thus, the uncertainty principle actually states a fundamental property of quantum systems and is not a statement about the observational success of current technology.[9] It must be emphasized that measurement does not mean only a process in which a physicist-observer takes part, but rather any interaction between classical and quantum objects regardless of any observer.[10][note 1]
Is this true? I didn't think there was any kind of consensus on this topic. I also thought some scientists believe the Planck time(/length) is the smallest unit of possible time i.e. they would say time is discrete