Davy_Jones

Coulda swore you're the fella that told us (in another thread) that science doesn't deal in metaphysical hokum like truth and reality. But getting back on point . . . my first thought would be that neither the concept SCIENCE nor PHILOSOPHY can be captured in a definition. (following standard practice, DOG (in caps) denotes a concept; dog denotes a hairy animal ) "My concept of philosphy today is embodied in the idea of . . . " - @studiot Some of you may be aware of recent work in the study of concepts. Treating a concept as a definition is known as the "classical theory of concepts" (CTC). On this understanding, a concept is linguistic in nature, encoded as necessary and sufficient conditions (presumably in the brain somewhere). Take, for example, the concept BIRD. The classical theory would have us believe that this concept is encapsulated by a definition such as "feathered biped"; anything satisfying the definition falls under the BIRD concept. And that's that! CTC has fallen on hard times in recent years. Among other fairly catastrophic problems, it fails to account for what are known as "typicality effects". That is to say, and continuing with BIRD as our example, people do not treat all birds as equally bird-like. A sparrow, say, rates far more highly as a respectable card-carrying BIRD than does an cassowary, say. Moreover, subjects will assent far more quickly to a sparrow being granted BIRD status than an ostrich or a turkey. A cassowary, it would appear, is indeed a BIRD, just not a very good one. Contra the classical theory, it would appear that that is not that after all. There is more to being a BIRD concept than simply satisfying a definition.

Well, there's a rotten apple in every basket, eh?

Cough, cough. Trivia time, folks: Can you name a scientist who threw a party to celebrate when his life's work was flushed down the toilet? I take it on trust that prof Krauss is outstanding in his field (not unlike the scarecrow who won a Nobel prize). When he steps back from his own area of expertise, though, and gets philosophical about science, well . . . without meaning to be rude, it's almost painful to have to listen to. Personally, I see it as regrettable that certain scientists are not only ignorant of, but hostile to, philosophy. - Gerald Holton, "The Advancement of Science and its Burdens", p122

The Guardian says otherwise . . . "If you think religion belongs to the past and we live in a new age of reason, you need to check out the facts: 84% of the world’s population identifies with a religious group." https://www.theguardian.com/news/2018/aug/27/religion-why-is-faith-growing-and-what-happens-next

Well, not entirely. Any young Turk entering a lecture course on free will, say, or the mind-body problem, and expecting to come away with the answer (perhaps written on the back of a postage stamp), is in for a rude awakening. That's not to say his Anatolian time has been wasted, though. A great deal can still be learned. E.g. 1. What some of the greatest thinkers have had to say about these things. 2. A better appreciation of the complexities involved can be achieved. E.g. When you hear a Daniel Dennett or a Steven Pinker (both compatibilists) tell you that free will is real, they have something quite different in mind from a John Searle, say. So, I'm genuinely grateful to all who have contributed. Next time my children (if I ever have any) ask "Daddy, is gravity a force?" I'll tell them "Shut up and do your homework" . . . er, I mean, I'll tell them "Ah, it's not a simple question, son, but I can tell you what some very clever people have to say about this". Point well taken. Obviously when Professor Lincoln, say, is delivering a series of lectures to a lay audience he will not be speaking the same way as he he does when talking to his peers. If he did, I'd demand a refund.

Thanks again, @Markus Hanke Perhaps a little off-topic, but I'm genuinely curious . . . This calls to mind the position known as conventionalism, associated particularly with Henri Poincaré. We see this kind of thing, for example, in the so-called "units of selection" brouhaha in evolutionary biology. There are those who hold that there is a fact of the matter as to what is being selected (individual orgamisms, groups of organisms, genes, etc.); others claim this is simply a matter of convenience or convention -- pragmatics, if you like. More pertinent to general relativity, Poincaré maintained that there is no fact of the matter as to whether space is Euclidean or not. Again, which system we choose to adopt is purely a matter of pragmatics, simplicity, convenience, convention . . . https://en.wikipedia.org/wiki/Henri_Poincaré Is this a position you subscribe to yourself? Or do you believe there is a fact of the matter as to the geometry of physical space? How about other physicists?

Just a couple of thoughts for all to ponder for now . . . Can you bear one more Einstein quote? Just one last time, I promise. What Einstein is telling us here, and as is well known to philosophers and historians of science, is that scientists--with the best of intentions--frequently misdescribe what it is that they are doing. If it's any consolation, don't feel too bad; everybody else in the human race does it too, at least from time to time. I very humbly and respectfully suggest that's what's been happening here, at least to some extent. Whenever some annoying philosophical asshole (e.g. me LOL) gatecrashes the physicists party and asks questions about truth and reality, what we hear is something like the following (paraphrased with elements picked from various comments throughout the thread, either explicitly stated or implicitly implied): "Oh, don't be silly. You obviously know nothing about physics. We just construct models which can be regarded as simply tools, and describe behavior. We don't use words like truth and reality and belief, or if we do, we hedge them with 'scare quotes'. Our models (which we prefer to the word theory) are simply instruments, not the kinds of things that can even be true or false. Science does not address questions such as "What is the fundamental nature of gravity? or the fundamental nature of anything else; we leave that to metaphysicians and philosophers and other degenerates. We simply describe behavior; physics is not in the business of going behind the scenes and offering explanations to 'why' questions." (Having fun here, folks. Don't take this too seriously ) But, but . . . after that annoying philosophical asshole has been given a good beating and ignominiously thrown out the door head first, the physicists crawl out their shells again, look around nervously, and revert to their normal modes of speech. Now, I've only been up for an hour or so this morning. Over a nice breakfast and a mug of coffee I enjoyed Prof. Don Lincoln's (see earlier in thread) lecture 18, "The Case for Cosmic Inflation". Prof. Lincoln ends the lecture with this: "Ok, so that's the story of inflation which is most certainly not a theory that you should believe outright. But it's a theory that is a very good candidate to explain the observed uniformity of matter in the universe and the flatness of space. It might be true, and if it is, it will definitely make the news." After that, I had a quick browse through your wonderful forums here. First thing to catch my beady reptilian eye was a passage from Wiki which @TheVat posted a few hours ago in the thread "Why does it seem to us that the universe is expanding where there is no gravity" . . . "Since the 1990s, dark energy has been the most accepted premise to account for the accelerated expansion. As of 2021, there are active areas of cosmology research aimed at understanding the fundamental nature of dark energy..." Conclusion: I very humbly (grovel, grovel) suggest that comments such as those above are perfectly typical of the way physicists speak . . . when pests like me aren't around LOL.

I don't see the problem myself. If the thread offends you, can't you just ignore it? And I've no objection at all to the mods relocating the thread if they feel it's misplaced here. I just felt if I was going to get some intelligent input to my question it would most likely come from physicists. That's all. Not meant that way at all. Hey, it was you guys that came up with the phrase.

See OP. I invited the mods to locate the thread as they saw fit.

Almost certainly not. But hey, we might learn something along our merry meanderings.

@Markus Hanke Thanks once more for the response. It seems to me that by using the term "formalism" here you may be guilty of begging the question, presupposing that which we are supposed to be examining (i.e. "Can GR be given a realistic interpretation?"). By speaking of formalism, is it not the case that you've already assumed the answer is no? That is to say, "formalism", at least as I understand the term, implies precisely a mere mathematical structure or framework; a skeleton, if you like, bereft of any ontological commitments. Consider, for example, this remark from Murray Gell-Mann: "Quantum mechanics is not a theory, but rather a framework within which we believe any correct theory must fit" "Framework" here seems to me pretty much synonymous with "formalism". Does that sound reasonable to you? And indeed, under the orthodox Copenhagen antirealist-instrumentalist view, at least as far as I understand, the formalism is all there is to it. Don't ask what's going on behind the scenes. Don't ask what's happening when no one is looking. Don't ask what it all means. Shut up and calculate. Etc., etc. Of course, not everyone is satisfied with such a purely instrumentalist understanding of QM. Attempts have been made to give it a realist spin (David Bohm, multiple universes, etc), to put some meat on the skeleton, so to speak. Now, back to GR, is it not the case that the same applies? Yes, it can be treated as simply a mathetical device--as you're doing--prescinding from any ontological affiliation. On the other hand, Einstein's (the later Einstein) realist position, in this regard, is so well documented as to hardly need rehearsing. But oh, let's give Arthur Fine another twirl . . "In particular, following his conversion [from antirealism to realism], Einstein wanted to claim genuine reality for the central theoretical entities of his general theory, the four-dimensional space-time manifold, and associated tensor fields. This is a serious business for if we grant his claim, then not only do space and time cease to be real, but so do virtually all of the usual dynamical qualities." (I keep repeating Fine because it's the only quote I have at hand LOL. Whole books have been written on Einstein's mature realism, though.) Now, given that Einstein (just to name one) clearly was able to construe GR as a (or an attempted) representation of how the universe really is, on what grounds do you base your claim that it cannot be read any other way but instrumentally? -- unless, of course, this has already been presupposed to begin with.

@Markus Hanke @Markus Thanks so much for taking the time to share that thoughtful post under trying circumstances (= Thai Telecom lol). Before proceeding any further, though, I think we all need to get clear on a few essentials here. At certain times, indeed most of the time, I've been getting the impression that we're talking somewhat at cross purposes, probably due to our respective disciplinary backgrounds or interests (simply an uncredentialed philosophical dilettante myself), and perhaps the way certain terms (e.g. realism, observability) are used differently in different domains. @TheVat is the only contributor who I feel is, if not always in agreement, at least perfectly clear on what I'm saying. And yes, I do appreciate and acknowledge that I'm the philosophical Blood on physicist Crip turf. Don't shoot! I'm unarmed! 1. You say above ". . . since both A and B are descriptions of reality, but not reality itself. Like maps of a territory." Other members have said similar things (e.g. "the model is not the reality" - MigL) earlier in the thread. Surely this does not even have to be said. Regardless of whether we use the term theory or model or whatever, surely no one confuses a painting of sunflowers with actual sunflowers, no one mistakes a book about Van Gogh for Van Gogh, and no one thinks a model Boeing 747 is a Boeing 747. The salient question, rather, is whether or not physical theories or models accurately represent reality, or at least endeavor to do so. 2. The view has been expressed in the thread that physics does not, or does not try to, represent reality. I'd been assuming that we all tacitly understand this to mean unobservable reality, but I'm beginning to have my doubts. Where I come from at least (Blood territory), everyone accepts that physics describes observable reality, indeed describes it very well. Fire a cannonball, say, and physicists will tell you what trajectory it will follow. The dispute between the scientific realists and antirealists, rather, is whether science can or should do more, can or should science try to go behind the scenes, so to speak, can science "lift a corner of the veil" (Einstein's phrase), should science settle for "saving the appearances" (e.g. simply describe the trajectory of the cannonball) or go further and provide us with a causal-explanatory account of why the cannonball does what it does? And as we've seen, even in physics, universal consensus by no means obtains on these matters. Antirealism ("Don't even ask what's going on backstage. Just shut up and calculate") does appear to be the prevalent position, though, as I've shown, I hope, Einstein and Weinberg constitute two very notable exceptions. It strains credulity to suggest that the realist camp consists of precisely two members; there are surely others of similar persuasion. So to your post . . . "So, asking whether gravity “really is” A or B, or whether A or B are “true” is fairly meaningless, since both A and B are descriptions of reality, but not reality itself. Like maps of a territory." - Markus If one assumes an instrumentalist (a form of antirealism) position on these matters then it is indeed meaningless to ask whether A or B is true. The instrumentalist--and you sound like one--holds that scientific theories/models are not even candidates for truth or falsity . . . not unlike a hammer or a screwdriver or an adjustable spanner (er, that's a monkey wrench to my American brethren). It makes no sense to ask whether a hammer is true or not. But, as I've tried to point out in the thread, not all scientists, indeed not even all physicists, are instrumentalists. There are scientists, I suspect the vast majority (physics being the exception), who do feel that the predicates true and false are applicable to scientific theories. E.g. - Einstein, essay "On the Generalized Theory of Gravitation" - Steven Weinberg, "The Science Wars", p220

Do you have a Swahili version?

Re above: That looks like one for the physicists (isn't it?). I'll keep my trap shut for now. But your logic seems impeccable. If one can exist in the absence of the other then they are not identical. Thanks for the tips on quoting, etc. (Though it's awfully tempting to invoke Saul Kripke's "modal argument" which purportedly refutes the psycho-physical identity theory. Aaaaarrrrgggghhhhhh!!!!!!) Edit: Oh, what the heck, let's just throw Kripke in here and see what happens LOL. There are those who claim that mental states are identical with physical states. This is the so-called psycho-physical identity theory. Pain, for example, is sometimes claimed to be identical with a particular brain state, which we'll simplistically call C-fiber firings. Kripke demurs: 1. If pain is identical with C-fiber firings, given that the two terms are rigid designators (i.e., designate the same thing in all possible worlds), then they would have to be necessarily identical, identical in all possible worlds. 2. Pain and C-fiber firings are not identical in all possible worlds (we can conceive of pain without C-fiber firings) 3. Pain and C-fiber firings are not necessarily identical. Conclusion: They are not identical. Now, even supposing this works for psycho-physical identity, would it work for gravity being a force of a certain kind? Edit #2 : Hmm, on second thoughts I don't suppose this is relevant. Seems we're only interested in whether gravity is a force in this world, i.e., contingently identical.

Er, that's my raison d'etre right now. Hoping for an answer to that question is the reason I started the thread. Edit: How do I remove unwanted items like vids or pics when quoting another member? Not wanting to hog the screen, I just wanted to quote your sentence at the end. Edit #2: Sorry, Studiot. I misread. Can you direct to the exact post you're referring to, please? I do read everything that's posted, even if I don't always respond . . . often because the more technical parts fly over my layman's head.

I'll check it out . . . just as soon as I'm allowed back in the library again. Grrr!

I'm a little disappointed myself at the paucity of responses to the above (from the previous page).

Oh, certainly true, at least some philosophers. The compatibilist notion of free will comes immediately to mind. Next up, the eliminativist stance towards consciousness (e.g. Daniel Dennett). Seems to me a copout. "It's a tough problem so let's just explain it away".

I'd say so. To have an effect on other things is to have causal powers, and to have causal powers seems to me a sufficient condition (though not a necessary condition - see * below) for being granted reality status. Conversely, that which does not exist (i.e., is not real) has no causal powers; can affect nothing. You may have noticed the brief ramble @studiot and myself took near the bottom of page 4 into the reality of Harry Potter and the luminiferous ether. Studiot, I think (correct me if I'm wrong), was suggesting that both Harry and the ether are somehow real, on the grounds that many people have been affected by them. What I said to that, perhaps naively, is that (as far as we can tell) neither exists, neither is real. And if that's so, no one has ever been affected by either inasmuch as non-existent entities have no causal powers. What has had a causal effect on people is their beliefs about these things. (As others have noted, it's mighty awkward to even discuss these matters without apparent contradictions arising; just to call them things seems to confer reality upon them.) * There is a position in the philosophy of mathematics known as Platonism (him again!) which holds that numbers are real, but they exist in some ethereal (that again!) Platonic realm. If true, this would be a case of something being real, though devoid of any causal powers. Philosopher of science Ian Hacking, meanwhile, defends scientific realism, unlike any other I know of, from the perspective of actual experimental practice in science, his maxim being "If you can spray them, they're real". More generally, we might say if you can manipulate these . . . um, thingies, or whatever you want to call them, then they're real. Ah, it's the old "Cloud of Theseus" conundrum all over again . . . https://en.wikipedia.org/wiki/Ship_of_Theseus Edit: The Ship of Theseus conundrum elicits different intuitions in different people as to whether it's the same ship. I don't think anyone denies, however, that both ships (or is it one ship?) are real. Same, presumably, applies to your clouds. The problem is one of individuation, not reality.

@joigus A very thoughtful post you've offered there with a great deal to ponder. As it happens, and for all it's worth, my own proclivities in these matters would be located somewhere towards the antirealist end of the spectrum, which would seem to put me in good company here. That said, the realists do have some pretty powerful arguments on their side that I think have to be acknowledged and addressed. So let me play devil's advocate here for a while. (Bliss on tap! Ooh ah!) Take a look, if you will, at the following list of subatomic particles which, we are told, have been discovered since the year 1800. https://en.wikipedia.org/wiki/Timeline_of_particle_discoveries Now, I assume the entities on the list, with the exception of any serendipitious discoveries (X-rays?) which just kinda popped up out of the blue prior to starring in any bright spark's PhD dissertation, were originally posited as theoretical entities, perhaps regarded as "useful fictions" to begin with, much as atoms were until roughly a century ago. We might have been told that to enquire into the existence of such spooks was to perpetrate the heinous sin of metaphysical speculation. Science can't answer questions like that. Just shut up and calculate, etc., etc. Given, however, that these spooks were subsequently "discovered" . . . well, to my untrained ears, discovery pretty much entails reality. And if they're real, is it not the case that physics is--at least to some degree--describing reality for us? Speaking as a physicist (I assume you are), do you consider the entities on the list to be real? If not, why not? If yes, how do you reconcile these additions to our ontological inventory with the passage of yours which I have quoted below?

The above was in response to my: QUOTE Near the end of Lecture 15, "The Awesome Evidence for General Relativity", at the 28:30 mark, Prof. Lincoln perorates: "I hope I've convinced you that there are very good reasons that general relativity has been very clearly validated. I mean I know that it's very weird to think of gravity as the bending of space and time, but it's just literally impossible to believe otherwise these days." So, pace other contributors to the thread--perfectly entitled to their opinions--who have told us that no one knows what gravity is, or science cannot answer questions such as what gravity is, clearly, Prof. Lincoln does not share your skepticism. The good professor is not only telling us what gravity is (It's the bending of space and time), but that to believe that gravity is anything other than the bending of space and time is not possible. A tad hyperbolic if you ask me, but hey, I toss it out here for consideration. UNQUOTE Since the professor is now with us, perhaps he'd be kind enough to expatiate. Am I reading too much into what you said, sir?

To that I can only offer the words of a very wise man . . . "Science without epistemology is -- insofar as it is thinkable at all -- primitive and muddled" -- Albert Einstein

I'd like to quote once more from Prof. Don Lincoln's marvellous lecture series (see above). Lecture 16, "The Hunt for Gravitational Waves", 5:50 mins . . . "Gone are the days of Newton's force of gravity. According to Einstein's equations, gravity is literally the bending of space" Two questions for Don and everyone else: It has been expressed in this thread that science cannot answer the question "What is gravity?" (on the grounds that it's metaphysical). Q1: Isn't Einstein doing exactly that? Isn't Einstein saying the answer to the question "What is gravity?" is "the bending of space"? (Even if the answer is wrong, he is still providing an answer.) It has also been expressed in this thread that no one knows what gravity is. Q2: If Einstein's theory is correct, is it not the case that lots of people know what gravity is? Namely, all those who believe his theory.

One can only wonder where you're typing that post from then And mind your own business. It's the job of philosophers to say things like "reality doesn't exist" LOL (I'm kidding)

@DrDon First and foremost, I'm thrilled you're able to join us. Why, I feel a little weak at the knees as I type this LOL. I've been thoroughly enjoying your Great Courses "The Evidence for Modern Physics" series . . . for the second time! Up to lecture 17 so far, but what the hell, since you're here I'm gonna watch the whole Megillah again and keep notes of stuff I'd like to ask you (er, do you charge?) . . . then mercilessly bleed ya dry! You have a wonderful delivery, moreover wit and self-effacing humor that is very endearing. It's just that Tom Cruise smile at the end of every lecture that needs a little work. Hahahaha! I'm in no position to question your expert knowledge in physics; happy enough just to drool in awe as @TheVat probably did over Isaac Asimov (he's such a name-dropper, eh?). Seriously, though, there are some things you say, e.g. regarding proof, confirmation, evidence, etc. (the bread and butter of the philosophy of science) that I think we might discuss productively. Alright, that's it for the phatic pleasantries. We'll get our hands dirty starting from next post. P.S. Any chance of a signed copy of that new book? Well, things are never quite that simple. When data sits uncomfortably with theory, one option is to declare the theory false like a well behaved Popperian and head off to the pub to drown your sorrows. There are, of course, other options. 1. Do nothing at all. Scratch your head and wonder why data is so recalcitrant. Or more commonly . . . 2. Declare the theory to be perfectly healthy and try to find some way to reconcile the awkward data/evidence with the theory. The problem does not necessarily lie with the theory; it may lie with the "auxiliary hypotheses", "background knowledge" or whatever you wanna call them. After all, when it was noticed circa 1850 or so that Uranus was not behaving in the manner Newtonian physics predicted (i.e. data/evidence clashed with theory) I doubt it crossed anyone's mind that Newtonian physics might be at fault. What they did instead was say "There must be something wrong with our background assumptions. Hmm, perhaps there's something out there that we're not seeing . . ." Enter Neptune. Can't resist getting started right away. This is exciting Well, first of all, "belief" is a scientific word; it's part of the standard ontology of psychology. More to the point, though, with regards your comments above, as I've cautioned other members, I'd be a little wary of speaking for all scientists. They're an eclectic mob, ya know. As for "consistent with all relevant known data" . . . do you know any theories like that? Steven Weinberg again: Steven Weinberg, "Dreams of a Final Theory", p93 Things are about to get a lot heavier . . . @DrDon, you tell us: " "Belief" to a scientist simply means in this context, that the theory is consistent with all relevant known data and we can take it as an approximation of the truth." and "Accordingly, I feel quite comfortable in saying that I believe in general relativity in the realm in which it is applicable. Similarly, I believe in Newtonian gravity in the realm in which it is applicable." Once again the fire-breathing dragon of consistency rears its ugly head. We're all agreed that both theories yield accurate predictions. That said, both theories are conceptually wildly at odds with one another. Both theories make logically incompatible claims. In other words, if one theory is true, or approximately so, it is not logically possible that the other is, or even approximately so. For example, if Theory A claims that space and time are absolute and uniform, Theory B claims that they are not, as a matter of simple logic, both cannot be true. - "On the Methods of Theoretical Physics", Albert Einstein,