Davy_Jones

Quite so, Mr Vat, There are certain statements that scientists make, or theoretical entities posited, which are obviously not meant to be taken literally. Swansont mentioned red quarks or something (can't remember exactly). Or consider point masses and ideal gases, perhaps. Anyone who takes these things literally is . . . well, missing the point . . . massively. Duh! But it's not always so obvious how a statement or a theory is to be interpreted . . .

Einstein's views on these matters are well documented, sir. Would you like me to recommend some reading? I'm not being sarcastic. Gripping stuff indeed. Or at least I thought so.

No, that's not my goal. You've been telling us (and I quote) "we know physics isn't trying to describe reality" What I've been showing is certain of your peers, including some of the finest (Einstein, Weinberg . . ), apparently didn't receive the memo; they don't "know" what you (plural) "know".

The obvious problem with simplistic comments such as these is that scientists themselves disagree over how scientific theories or statements ought to be understood. Contrast, for example, Duhem and Einstein's radically opposed understanding of scientific theories (near the bottom of page 2). Indeed, the very same scientist may not be consistent in his interpretation of statements or theories. If you'd asked the Mach-influenced Einstein circa 1920, perhaps, how his general theory of relativity ought to be understood, you'd likely have been told something like this: "It's a mathematical instrument, not to be taken at face value, not to be read literally." Twenty years later, you'd have heard something quite different. Perhaps . . . "My theory is to be understood as a representation of reality. It should be read literally." Our old pal Arthur Fine again . . .

Ok, thanks for explaining that.

Well, you're the scientist and I'm here to learn. Is there a universally agreed upon definition of force in science at present? One thing we can say, I think, is that these things do tend to change, even in science. If I'm not mistaken, Newton's action-at-a-distance concept of force was fiercely resisted for quite some time, especially on the continent. "You call THAT a force!!??" - the French Correct me if I'm butchering the history.

Ok. Still listening . . .

Fine. Go on . . . Quite so. I edited my previous post before seeing this. I changed "their belief in the aether" to "their beliefs about the aether". Not all scientists believed in it, but they all (the ones relevant to us) had beliefs about it.

Of course it has. But note: what affected people was their beliefs about the aether, not the aether. On the assumption (current scientific orthodoxy, I believe) that the aether does not exist (i.e. is not real) then it never affected anyone.

Ok, how about the luminiferous aether? Hmm, the history of science also has no shortage of concepts which turned out to refer to nothing.

Your reasoning above is a bit like saying many people have been affected by the Fountain of Youth. Ponce de Leon (was that his name?) squandered years searching for it. Said Fountain, as far as we can tell, does not exist; it is not real. But Ponce de Leon believed it existed. It was his belief doing the causal work. I'm using the term belief in the everyday sense.

I've added numbers to your points above for convenience. 1. Ok. I hereby offer Harry Potter (Doubtless there are lots of people named Harry Potter out there. I mean the fictional character we both have in mind right now.) 2. We might conduct a search. Pretty sure we'd never find him, though. 3. I don't think so 4. No (but see 1 above) 5. Many people have been affected by their beliefs about Harry Potter. Said belief corresponds to nothing in reality. I throw these answers out--somewhat diffidently (lol)--to see what happens next. What do you think?

To the contrary, I suspect Dawkins would throw a fit. If truth is subjective then the Creationists' truth is just as good as his own. It's all relative, eh? Bring two guns "Gravity is not a version of the truth. It is the truth. Anyone who doubts it is invited to jump out a tenth-storey window." - R. Dawkins (It's a very silly comment, but gives you some idea what he thinks of truth) Well, as I hinted at in the OP, I'm not sure it's possible to examine a question of this type without delving into a li'l philosophy. And I'm very grateful for it, sir. (your own emphasis) And your point is? Did you notice the bit about "describing the physical world"? Read that as "describing reality".

There are also people (known as instrumentalists) who feel that scientific theories are nothing more than a tool, or a model, or an instrument for calculation, not subject to the predicates true and false. But if you think all scientists subscribe to instrumentalism, think again. Try asking Richard Dawkins, say, whether he thinks the theory of evolution is merely a tool with no bearing on the way things really are. You might wanna bring a gun. We touched on this earlier in the thread. Now, if you are treating the two theories as mere instruments (as described above), there is no problem. On the other hand, if you are presenting the two theories realistically--as the way things really are--then, assuming that the curvature of spacetime is not a force, you would be making two inconsistent statements. You would be contradicting yourself.

Because whether or not physicists purport to describe reality is relevant to how we should read a statement such as "Gravity is a fundamental force" or "Gravity is the curvature of spacetime". Should such pronouncements be understood as a mere façon de parler, not to be taken at face value, or are we being told this the way things really are. And who has the final word on these things again?

Oh, I agree it's ludicrous nowadays to think that Newtonian physics describes reality. Times have moved on. But this is to miss the point that for two centuries or more, Newtonian physics might as well have been carved in stone. I daresay it was almost universally taken to be a faithful description of reality. In other words, a great many physicists (I'm tempted to say the vast majority) did not find it remotely ludicrous that physics--at least sometimes, at least physics at its very best--can describe reality. And I daresay many still do. Looking forward to hearing what @TheVat's pal Don Lincoln has to say on all this. Edit: What you seem to be saying, swansont, if I'm understanding you right (please correct me if I'm wrong), is that we should not believe anything physicists have to say about unobservable reality (quarks, bosons, and all the rest). After all, it's all--on your account-- just models, and "making up stuff", and "we know physics isn't trying to describe reality". Is this a fair representation of your position? If it's any consolation, it's a position I'm not unsympathetic to myself. I'm just afraid a riot might break out at any time.

Dude, antirealist is not a synonym for anti-science. Sigh! Many of the finest scientists have held antirealist views. Try this: https://plato.stanford.edu/entries/scientific-realism/ "All this [i.e. Kuhn's ideas] is wormwood to scientists like myself, who think the task of science is to bring us closer and closer to objective truth." - S Weinberg Physicists are not searching for truth, you say? Evidently, at least one is. You think he's the only one?

I repeat once more, you are perfectly entitled to your opinion that physics is not about describing reality. That is what you're saying, right? Indeed, in your antirealist corner stand some of the very finest physicists, including Niels Bohr whom you quoted earlier. My only animadversion is that every time you say such things, they are never qualified by a humble "in my opinion" or "of course not all physicists feel as I do". Rather, what we see instead is invariably an unqualified "Physics is not about describing reality" as if a statement of undisputed fact is being presented, as if there is an unspoken "and that's all there is to it!", as if to say "ask any sensible physicist and they'll tell you the same thing". (at least that's how your peremptory pronouncements strike my ears) This is what I find objectionable. Why, some of our more naive, wet-behind-the-ears members (if there are any) might even be beguiled into thinking that's the end of the story, there's nothing more to discuss. That, of course, is not the end of the story. It is not a fact that all physicists feel as you do, that physics has no business describing, or at least trying to describe, reality. Surely no one here needs reminding of Einstein's heroic realist stance against (what he saw as) the prevailing antirealist tyranny of Bohr, Heisenberg et al. But he's six feet (depending on your frame of reference) under, you might well retort. Among contemporary physicists, I can think of no more staunch realist than Steven Weinberg. One can barely turn the page of one of his popular expositions without tripping over antirealist bogeymen such as truth and reality. Here's a tantalizing teaser . . . - Steven Weinberg (from "Facing Up", essay 4, "Confronting O'Brien") - Steven Weinberg (from "Facing Up", essay 17, "The Non-Revolution of Thomas Kuhn") Clearly, not everyone shares your view that "we know physics isn't trying to describe reality". Pfft! That's nothing. I once met (while in your beautiful country) the keyboard player from Sparks. Remember? The dude that looks like Hitler. Edit P.S. Whoops! I just googled Steven Weinberg. Turns out he's six feet under too, as of a few weeks ago. RIP!

A slight correction. What I actually said was: "Given, however, that the two theories make logically incompatible claims, it is not possible that both are true" Of course, neither is believed to be true nowadays.

"Discover" is what they call a "success verb". If the top quark has indeed been discovered, then our understanding of reality just increased by one ontological unit. It's in the bank, so to speak. What a name-dropper! I mean yes pleeeeeeaaaaaase!!!!!

@swansont Re above You did say on the previous page . . . "I argue that would be physics, and the reason that we know physics isn't trying to describe reality is because physics itself admits that it's making stuff up to make good models. Nobody claims that electric field lines physically exist. Phonons are quantized vibrational modes of a structure - not physical particles that exist independent of that structure. Electron holes are the absence of electrons, not some particle that exists on its own. These things aren't real, physical entities. They are calculational and conceptual aids to modeling behavior." Given that--on your account-- "we know physics isn't trying to describe reality" and that physics "makes stuff up", how exactly are we to understand an announcement such as, say, "The top quark was discovered in 1995"? Something unreal was discovered? The top quark has been discovered by physicists dabbling in metaphysics on their day off? (I asked on the previous page. You didn't answer.) Now, if the top quark has indeed been discovered, and it is real, would it not be fair to say that physics has added to our knowledge of reality, we have a better understanding of reality now thanks to physics, our description of reality is more complete than it hitherto was, or some such locution?

"True" here means valid. i.e. we have confidence that the theory can be applied and give god answers. But it's still all about behavior and observation, and not about any underlying reality. So, just to be clear, what you're saying is that in your opinion scientific theories are not about any underlying reality, that's not the business/aim of science . . . though other scientists may have different ideas? Given that the final clause (in red) was presented as an unqualified blanket assertion (and not a personal opinion), I took it to be just that.

@studiot above Well, swansont and myself were talking about the aims of science. Swansont is telling us, it seems, that science does not try to get at underlying reality. Is that right, sir? Are you (or swansont) seriously suggesting that all scientists in all times and all places have exactly the same view about the aims of science? I've an idea: why don't we just ask them!

First quote I could find . . . [...] That phenomenon is conversion. Max Planck is often quoted to the effect that 'new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it'. A similar sentiment was expressed a half-century earlier Harvard's Professor Joseph Lovering, when he told his students that there are two theories of light, the wave and the corpuscular. Today, he is said to have remarked, everyone believes in the wave theory; the reason is that all those who believed in the corpuscular theory are dead. There is a measure of truth in such statements, as we all know, and yet a new scientific idea does win adherents, and even convinces some opponents, as has been seen in many examples throughout this book. - Revolution in Science, J. Bernard Cohen, pp 467-468 Don't make me go searching through the forums for members believing such-and-such a theory. Pleeeeeaaaase!! If no one believes these things are real, as you claim, why do I keep hearing--every few months or so it seems--that some new subatomic particle has been discovered? How can that which is not real be discovered? Prof. Lincoln again (our friend from above):

@swansont (Pardon my clumsiness with the quote function) "How do you empirically determine the "best" explanation without invoking philosophy or other assumptions?" - swansont You don't. The explanatory power (along with simplicity, etc.) of a theory is what's known as a non-empirical epistemic virtue. As I said earlier, strict empiricists will have no truck with this; the only epistemic virtue, on their account, is fit with the facts. (sounds a lot like you, sir) Now, you may or not like it yourself, but many scientists routinely invoke explanatory goodness as a reason for believing some theory or other. Try asking Richard Dawkins, say, why we should believe the theory of evolution. You're likely to hear something like this (and I paraphrase): "The theory of evolution provides the best explanation for all the empirical data we have. It provides a far better explanation than the theory of special creation." (and the tacit inference is: explanatory power confers epistemic warrant; explanatory goodness is a reason to believe a theory. Otherwise why mention it at all?) " "True" here means valid. i.e. we have confidence that the theory can be applied and give god answers. But it's still all about behavior and observation, and not about any underlying reality." - swansont Again, you continue to speak as if "Ask any scientist and they'll tell you the same thing". I repeat, scientists are a heterogeneous bunch; they say all manner of things about the aims of science. There are, of course, scientists who believe as you apparently do: science is not in the business of getting at an underlying reality; the job of science is to "save the appearances" and stop right there! E.g. - Pierre Duhem Meanwhile, in the red corner, here's another scientist who feels otherwise. The job of science, difficult though it may be, is to to go beyond mere appearances (the outside of the watch) and try to get at that underlying reality (the inner mechanism). - Albert Einstein