Seeing as your responses have degenerated into hostile retorts, I don't know if it is worth continuing this conversation. But I'll give it another try.

We require reasons and explanations for everything. We are not satisfied with brute facts. Things lacking an explanation are unintelligible to us. — SophistiCat

And yet you don't seem to be able to explain how reason is "not at all like this" or give an example of some reasoning which is not like this. So why should I not believe you are indulging in bare assertion? — Janus

As I said, I discussed this in my preceding posts. The context in which the "rationality" of the world or the acceptability and intelligibility of brute facts show up is pretty much limited to a line of philosophical questioning in the mode of the PSR - and here, of course, opinions differ. By contrast, in our ordinary and scientific reasoning such questions are largely irrelevant. We deal with a world that is partially intelligible, as far as we are concerned, we deal with it piecemeal, and we seem to do fine that way. Our inquiries seek to illuminate some regularities and connections, which abut on assumptions and probabilities that are not themselves accounted for within the context of the inquiry. Any such inquiry leaves out of its scope the vast majority of the world, which, for all it matters, could be shrouded in darkness. And this limited comprehension is what we usually understand by explaining, finding causes and reasons. We do not require the world to be totally rational and noncontingent before we can say that we understand something about it.

My conclusion is that the PSR cannot claim to be a phenomenological principle that faithfully captures the way we actually reason.

Your allusions to the existence of more exhaustive accounts or counterexamples do not help me; It would be far more helpful if you actually gave some more exhaustive account or counterexample of your own. — Janus

I wasn't alluding to counterexamples. My point was that words such as "reason," "cause" or "explanation" are too controversial to be employed in a thesis without unpacking their meaning. I have discussed the way I believe we actually reason, but I am not the one advancing a PSR thesis. It is up to a PSR proponent to explain what they mean, and why.

I have pointed out how our actual reasoning is not nearly as comprehensive as an unrestricted PSR suggests. Another important question to consider is how subjective it is: how much of the perceived "rationality" of the world is in our heads, vs. being a direct impression of the way the world actually is. I think there is some of both. On the PSR-friendly side of the dilemma, our very existence and our rational faculties seem to require an objectively regular environment. But on the other side, the multiplicity of working accounts of the world casts doubt on the idea that there must be a unique, objective and comprehensive Reason for everything.

Just one small but illustrative example: anthropic explanations in fundamental physics and cosmology. Briefly, the trajectory of physical and cosmological theories typically leads scientists towards mathematical models that are themselves taken to be the brute facts of reality - albeit with a hope held out for their reduction to an even more accurate and comprehensive system of mathematical structures and constants as science progresses. However, a radically different explanatory terminus has been suggested in the latter half of the last century (if not earlier): our very existence as "observers," living creatures with the ability to make observations and come up with such theories - a Cartesian turn, if you like. (Fred Hoyle's prediction of a hitherto unknown quantum state in carbon-12 is often cited as an example of anthropic reasoning, although this interpretation is disputed.) You may have also heard about so-called fine-tuning of the fundamental constants: the constants "had to be" within such-and such narrow range in order for the universe to be able to produce and support living creatures like us. Not everyone likes this anthropocentric framing, but it does have some appeal, even if we are trying to be objective about it: after all, our own existence is the one thing that we can believe with more confidence than anything else! Why not this as at least one of the reasons?

an omnipresent being, is naturally indivisible — ShowOfForce

Why? Your only stated reason is that it just can't be. Something that is present in some, but not all places can be divisible, presumably. Why not something that is present everywhere?

Now, since this entity is everywhere, undivided, where could another entity, possibly be located. That there, would be a division of being, within an indivisible consciousness. — ShowOfForce

Non sequitur. What does divisibility have to do with sharing space with something else?

No, the fallacy is the argument itself; in this case of the form: Trump made an assertion therefore the assertion is false. — Baden

That would not be a fallacy of reasoning, assuming my assessment of Trump's character as a liar and bullshitter is correct.

That's what I said, no? I don't really know what sort of an entity an omnipresent consciousness would be - but that's all the more reason for doubting pronouncements about it being possible or impossible for such an entity to be collocated with other entities.

For example, to dismiss something Trump says as false simply on the basis that he's a pathological liar is fallacious even if it's understandable. — Baden

To dismiss Trump's argument on the basis of his character would be a fallacy. But since Trump doesn't present arguments, that is rather a moot point. On the other hand, when Trump simply asserts something as true or false, you can reasonably and confidently dismiss that.

Good questions, and relevant to the OP, because they address communication in the context of an internet forum. — Galuchat

These are all good points, and of course, I agree, there are important differences between in-person communication and other forms. But such differences do not warrant totally discounting and disparaging communication on the internet as being of no value or importance. Also, it should be noted that internet communication is no different in this respect from old-fashioned letters or print publications. Talking on the phone features more non-verbal signaling than writing, but less than talking face-to-face.

Yes, the format provides a cloak of anonymity. Two things: the "cloaking feature" fades over time, over many interactions. "Real people" emerge from anonymity after a time. Some people here have been interacting for 10 years. The anonymity feature protects forum users from the ill-intentioned visitor, or the snoop. True, we don't list our actual names, addresses, telephone numbers, places of employment, and so forth. But if Tiff or T. Clark wanted to visit me, I'd hand over the information to them. — Bitter Crank

The anonymity of Internet forums is much exaggerated. So, you don't know my legal name. It's not like you know legal names of everyone you interact with face-to-face. And why is it important anyway? Does it matter to you whether you discuss free will or Aristotelian metaphysics with a John Doe or a Joe Q. Public?

And other than their legal names and appearances, forum members are not all that anonymous, as BC notes - in some ways they are less anonymous than people you know in "real life." Just as you recognize people by their appearance or voice every time you meet them, here you can always recognize them by their handles. And in all cases your impression of other people is formed by successive interactions with them. But whereas in other contexts you have to rely on your often faulty memory, here the complete record of everything anyone ever said is permanently on display! How is that for anonymity?

The main thing that makes Internet and other written communication more anonymous and impersonal is the absence of audio-visual impressions, which are important in themselves, and which I think make it easier to form and retain the impression of a person than just a name.

One of the problems with answering this question, using science, is the connected to the philosophy of science. As an example, say I had a dream. I relate my dream details to a group of scientists. My account would never be accepted as fact, even if I am honest and accurate, since my dream violates the philosophy of science. There is no way to verify my claims, nor is there any way for others to reproduce my dream, for verification. Yet, paradoxically, we have all had dreams and can understand that my claims are not out of the realm of possibility. However, it violates the philosophy. — wellwisher

That is factually incorrect. Dreams are a subject for science - and I don't just mean "objective" measures like REM observations, brain imaging, etc. - dream reports are in fact used in psychology and cognitive science. Similarly, religious scriptures and other historical documents of dubious factual value are used by historians. You just need to know how to work with your source material.

Fact is: nobody is truly (or genuinely) here. Hello! It's an internet forum; where usually the only thing you learn from other members is:
1) Who they want you to think they are, and
2) What kind of games they like to play under a cloak of anonymity. — Galuchat

And this is different from "real life" (or whatever you want to call it)... how?

This is such a last-century attitude towards communication on the Internet! For some reason it is taken as something less than real, something that cannot be taken seriously on pain of being mercilessly ridiculed by some dick. I could never really understand this. If you cannot see my face, or if you don't know my legal name, or if the interaction is mediated via digital rather than analog channels, then it is all so different? Why?

Or is your position that unless an interaction can result in physical violence, it cannot be taken seriously?

An omnipresent entity leaves no room for individuals, or fragmentation of any kind, because multiple beings can’t occupy the same space and remain separate. — ShowOfForce

Why? This is not true even about ordinary things - why should this be true about a hypothetical supernatural thing?

Well, in my opinion the PSR is wrong-headed, but specific criticisms need specific examples to which to address them. I don't want to dive into Spinoza, Heidegger or other historical works though, which is why I don't comment on them. I am more interested in live ideas than in philology.

If the PSR is not taken as a Kantian type insight into the fact that objects of knowledge must conform to human reason, then how should it be taken? — Janus

That's not much of an insight. Of course objects of knowledge conform to human reason - they wouldn't be objects of knowledge otherwise.

If you wanted to argue for the ontological provenance of the PSR, how else would you go about it other than in some variation of a Hegelian/ Spinozist or a Phenomenological/ Heideggerian mode of thought? In other words to merge the epistemological with the ontological or both with the phenomenological. Or some kind of theology perhaps? — Janus

Well, let's see how the slogan "Everything must have a sufficient reason" could be cached out.

1. Is it an observation about human reasoning?

1a. We seek reasons and explanations for everything. True, but obvious.

1b. "Objects of knowledge conform to human reason." Not sure what this is doing here, but again, a truism.

1c. We require reasons and explanations for everything. We are not satisfied with brute facts. Things lacking an explanation are unintelligible to us. This, I think, is closer to what some proponents of the PSR say, but as I argued previously, this is not true. The way we actually reason is not at all like this.

2. Is it a regulative principle?

2a. We should seek reasons and explanations for everything. This is a banality.

2b. Objects of knowledge must conform to human reason. Well, they already do.

2c. We must have reasons and explanations for everything. Brute facts are incoherent and unacceptable as objects of knowledge. This is closely related to 1c. Again, I think this is what some proponents of the PSR would say, but I do not agree with this.

3. Is it an ontological principle?

The only ontological formulation that I can think of is something along these lines:

3*. The world is "rational" (perhaps necessarily so): it is such that everything is amenable to explanation. Or, in a more standard form: Nothing can exist unless it has sufficient reasons for its existence and for the way it is.

This can also be seen as a prerequisite for (2c), because without accepting this principle, holding (2c) would be obviously irrational.

Here we should pay closer attention to what is meant by (sufficient) reason, cause or explanation (and the possible differences between these concepts). This is a huge topic, but it cannot be sidestepped in this discussion, because a lot depends on it.

And of course with the ontological formulation, more than with the other two, the obvious question is: Why believe this? Our experience strongly suggests that the world is a pretty orderly place, at least that part of it with which we are familiar. But that observation alone is far too banal to call it a Principle; on the other hand, stronger commitments seem both unwarranted and unnecessary.

I don't think it matters to the argument whether the PSR is present, as a formulated principle, in the minds of everyday people and scientists; the important point is whether they operate on the implicit understanding that everyday events and the objects of scientific study are capable of explanation. And I think the answer to that question is very obviously 'yes'. — Janus

As I said earlier, this modest observation that we do in fact look for explanations (in the broadest sense of the world) for things is not much of an insight. I mean, what else could we do? How else would we employ our reasoning faculties? It's a banality not worth even talking about, let alone calling it a Principle. And that's not what is usually meant by the PSR.

Posty operates under the misapprehension of the "Many Worlds" interpretation of QM as some some sort of anything-goes modal realism.

Lewisian modal realism dissolves the PSR, in the same way that the guillotine cures a headache. You can no longer demand an explanation for why A rather than B, since you've already assumed A and B (and C and D...)

Sorry, you'll have to direct this question to someone who knows more about Hume.

But Spinoza does allow for self-causing substance. In fact according to Spinoza all causation finds its ultimate terminus is "God or Nature" (deus sive natura). — Janus

Yes, the "ultimate terminus" is the Achilles hill of the unrestricted PSR, and philosophers have tied themselves into knots wrangling with concepts like causa sui. Although I think that being more critical and broadminded about the concepts of cause and explanation would be helpful here (and this goes for the Agrippa's Trilemma as well).

The weakness of this argument lies in the assumption that when people think of events as "unexplained or chancy", they are believing that the events are utterly random in the sense of having no cause at all. No one, if they thought about it, would deny that when the die is tossed, it interacts with the air and the surface it lands upon in ways which determine what face will show up. Events are only chancy for us insofar as we cannot predict outcomes, because we have no way of predicting the future, given that we only have a minimal grasp of all the determining factors. — Janus

What conclusions people reach when they specifically question things that they previously treated as "unexplained or chancy" will vary depending on the situation, available information and background beliefs. But this is not what I wanted to address in this argument. What I wanted to address was the notion that a PSR of some sort is indispensable to our everyday thinking (basic principles of thought @frank) and to science. I argue the opposite. Both everyday thought and science are oblivious to the PSR, unless they specifically focus on the question.

I don't think anyone genuinely believes that any event lacks an ultimate explanation. It is the very idea that any event could have no ultimate explanation that is inconceivable. — Janus

Well, this is not so much a philosophical question as a sociological one, and I believe you are very much mistaken in thinking that everyone is a causal determinist and believes in an unrestricted PSR. I know I don't. Della Rocca (PSR) bemoans the current low standing of the PSR among philosophers and scientists alike:

It sometimes seems as though, over the last, say, 271 years, a great deal of the best efforts of the best philosophers have been devoted to a direct frontal assault on the PSR. Despite their obvious and profound differences, Hume and Kant, for example, made it their mission to articulate and argue for a world-view structured around the claim that the PSR is simply false. Such attacks have been enormously influential to the point that they are simply taken for granted and philosophers now tend to presuppose — un-self-consciously operate under the assumption — that the PSR is false[...] And, perhaps even worser, there has been the testimony of contemporary physics which, in the eyes of many, tells directly and empirically against the PSR: for isn’t it a hallmark of contemporary physics that there can be certain facts without explanation? — Michael Della Rocca

ETA: The cosmologist Sean Carroll is one of those philosophically-minded scientists who rejects the PSR, for example in his recent article Why Is There Something, Rather Than Nothing?:

It seems natural to ask why the universe exists at all. Modern physics suggests that the universe can exist all by itself as a self-contained system, without anything external to create or sustain it. But there might not be an absolute answer to why it exists. I argue that any attempt to account for the existence of something rather than nothing must ultimately bottom out in a set of brute facts; the universe simply is, without ultimate cause or explanation. — Sean M. Carroll

ETA2: For fairness's sake, Paul Davies is another cosmologist who takes the opposite view, e.g. in this OpEd.

If you're thinking that defiance of the PSR can be found in cases of just not knowing the cause of X while accepting that there is some cause: no, that's not how it works. — frank

No, I agree, most typically the PSR implies the existence of a cause, whether known or not. My point when talking about our common-sense reasoning is that we do not, in fact, always assume the existence of a cause. Things that we (however fleetingly) take for granted are causeless in effect: the existence or absence of a cause makes no difference to our reasoning.

The same is true for scientific explanations: once we adopt some theory as our explanatory framework, it does not matter for us whether the theory and it posits can be further reduced to a causeless ground of all being or some such; giving account of phenomena in terms of the theory counts as providing an explanation regardless.

Suppose we find it reasonable to conclude that the Big Bang was causeless. The PSR doesn't say that we're unable to conceive the bang in some way. We can be fully confident that we're onto a brute fact. The PSR notes that the causeless part is inconceivable. Inconceivable doesn't mean nonexistent. It means beyond our ability to model in thought. — frank

So in terms of Frank's 'Big Bang' example, it could be, as he says a brute fact, and will remain so for us, even though it could alternatively be a self-caused, and thus in principle, self-explanatory, event. But confirmation of the latter possibility would seem to be closed to us; we cannot tell whether it is simply a brute fact, is self-caused or even caused by some other set of unknowable conditions. — Janus

Traditional proponents of the PSR, such as Spinoza and Leibnitz, as well as modern proponents like Della Rocca(1), Pruss(2) and Feser(3), do not accept brute facts. As Spinoza put it,

For each thing there must be assigned a cause, or reason, both for its existence and for its nonexistence. — Spinoza

Or,

There is a sufficient reason or adequate necessary objective explanation for the being of whatever is and for all attributes of any being. — Dictionary of Scholastic Philosophy

Even in his proposed weakened form of the PSR Pruss requires an account for at least the possibility of every contingent truth.

So whatever you two are arguing for, it does not look like familiar forms of the PSR, although there seems to be a strain of rationalism that is recognizable.

Moreover, when you say that some fact or state of affairs that lacks an explanation is "inconceivable" or "unintelligible" you don't seem to mean anything other than it does indeed lack an explanation, so you are not really saying anything at all - you are just restating the premise.

Or do really mean to say that something that lacks an ultimate explanation is inconceivable?



But that is nonsense. If we can describe and discuss something, then surely it is at least conceivable. As I argued earlier, we can and do conceive of things, without at the same time being aware of their causes or explanations. We do so all the time: in our everyday reasoning we always take some things for granted. When the need arises, we can put to question what was previously an assumption, but at the moment when we make use of the assumption, it does not matter whether it is necessary or contingent, and whether if it is contingent it has an explanation. Likewise, when we flip a coin, or when something happens "by chance," it does not matter to us whether the event was really, ontologically random or not - for all practical purposes, there was no explanation for why that event happened instead of one of its possible alternatives. We wouldn't think of it as random otherwise.

So psychologically, unexplained and chancy things are very much conceivable, and commonplace. Appealing to our psychological intuitions and using words like "inconceivable" and "unintelligible" rhetorically does not work in favor of the PSR.

The same goes for explanations. Proponents of the PSR, such as Feser, argue that an explanation that only goes so far as reducing one contingent thing to another contingent thing is not really an explanation. But that appeals to some contrived and question-begging notion of explanation, which is at odds with the way we actually employ the concept of explanation in our everyday life and in science.

(1) Michael Della Rocca: PSR (Philosopher’s Imprint, 2010)

(2) Alexander Pruss: A restricted Principle of Sufficient Reason and the cosmological argument (Religious Studies, 2004)

(3) Edward Feser: Can we make sense of the world? (2011)

I obviously wasn't talking about this "causeless ground of being." Whatever that is, I don't think it is required to conceive of brute facts and chances, as I explained above.

You might have a special ability to conceive the causeless. Just put that to the side if you dip into Leibniz or Schopenhauer. They had more trouble with it than you have. — frank

I don't think it takes any special ability. We naturally think in terms of chance and contingency.

In our ordinary thinking we hold some things as given (at least until we decide to hold them up for scrutiny) - those are brute facts. Other things are unknown, though they may be subject to some constraints (at least until we learn something new or recall something we had left out of the consideration) - those are chances. So we live and think as if there were brute facts and chances - whether this is in fact the case (and whether the question even makes sense) is another matter, but this reasoning scheme is natural to us.

The same has always been the case in science*. In any given scientific framework or theory some things (the assumptions and posits of the theory) are taken as brute facts, and depending on the theory, there may be chancy things as well.

It takes a philosopher of a certain bent to say: Wait a minute, these are not real chances, they only seem chancy to us due to our ignorance. And these facts that we take as brute must have some explanation.

* The special focus on quantum mechanics when it comes to chanciness is a result of reductionist thinking, where it is assumed that quantum mechanics reveals the true workings of the world, while all those other "special" theories, such as classical statistical mechanics or the theory of evolution in biology are only half-truths, convenient approximations.

No, when I say "chance" I mean absence of reason or cause. You can use a different word if you like.

We certainly seem to have reason-seeking instincts, but I wouldn't go so far as to say that we cannot help it. Chance, brute facts - these remain conceivable concepts, even if some would like to deny their actuality.

If the only thing in nature that is naturally reasonable is man, then what right do we have to declare that the rest of nature must follow along and be reasonable? We know a very little of what is in nature, maybe there are areas in nature where the PSR does not hold, how would or could we know, unless we say reality must conform to our understanding. — Cavacava

If we just say "reason" and leave it at that, then either we are making PSR an epistemological principle, or we are making some rather extravagant claims about the world somehow being imbued with "reason" (well, perhaps not so extravagant if you are a deist or a pan-psychist of some sort).

The trouble with a purely epistemological, regulative PSR is that it can easily dissolve into a banality. "We should always be looking for reasons, always try to make sense of the world" - well, who is going to argue with that?

PSR only really gets its teeth when it acquires some metaphysical commitments, as when "reasons" are cached out in terms of causes or entailments (@MetaphysicsNow).

Oh, I am not faulting you for not laying out an entire epistemology right here and now. My point is that historically* the PSR has meant something stronger and more specific than just having some reasons or motives or inclinations for believing this or that. Why even talk about some capital-P Principle if it is something so broad and vague?

* and contemporaneously, although it seems that the PSR, at least its less restricted versions, has rather fallen out of favor outside the circle of Christian theologians.

What usually distinguishes a PSR from any old belief system are more stringent requirements for sufficient reasons. You cannot just give a half-arsed excuse or say "Screw it, that's good enough reason for me!" You are supposed to doggedly pursue the chain of reasoning until some satisfactory resolution - a necessary state of affairs in the strongest formulations of the PSR.

The PSR, as I understand it, covers both causes and reasons. — Janus

First, we shouldn't be talking about "the" PSR without further qualifications. The SEP entry that Posty linked has a good intro chapter that classifies the various ways in which a PSR can be formulated and analyzed.

One important question that can be asked of a PSR is what constitutes a sufficient reason. You seem to make your requirements so loose that your PSR becomes nothing more than a requirement for having a sound epistemology, good reasons for belief (where what constitutes good reasons is left unspecified).

As an untrustworthy American, I say de-escalation is having NK stop threatening the US mainland. That kind of talk is bad joo joo for everybody. Trust me. — frank

So, deescalation means tampering down belligerent rhetoric for a while? That's a pretty low bar you are setting, but then chances are, based on past experience and other considerations, that that will indeed be the scope of achievement in the present iteration.

The pattern has been that NK ratchets up the threat level, then at the height of the confrontation it suddenly appears to back down and offers talks. Lots of pomp and ceremony follows; NK extracts temporary relief from its opponents in the form of lifted sanctions, aid and investment, in exchange for a temporary change of rhetoric, vague promises, and concessions that later turn out to be hollow or that it simply refuses to deliver.

NK is a survivor. It doesn't play a long game - it executes these political maneuvers in order to prolong its existence for a few more years. And I don't see anything in the present iteration that would seem to be any different from the past ones. There is no reason at all for NK to give up its highly successful nuclear program (successful politically, that is) and every reason for it to keep it up. As for the unification of Korea, that would entail a suicide for the present NK regime. If a unification ever happens, it obviously won't come about as a result of high-level negotiations with NK in its present state. Before a unification can happen, the regime will either have to be toppled or weakened to a great extent, or it will have to undergo extensive reforms.

I take the PSR to be an epistemological, not an ontological, principle. So Thorongil is right to say that it cannot be refuted, epistemologically and logically speaking at least, because to do so would be to find reason that the principle does not obtain: a performative contradiction. — Janus

How so?

First, as has been discussed here, the scope of the PSR may be limited to events or entities and not include "things" such as rules, principles, laws, etc.

But even if it did, the denial of the PSR would state that there is at least one thing that does not have a sufficient reason. That in no way contradicts the statement that there is one thing (the denial of the PSR) that does have a sufficient reason.

If there are natural events which are absolutely random, those events could never be anything for us — Janus

What do you mean?

Would you say yes or no to a prize for Trump? — frank

Why Trump? This whole Korean "rapprochement," for whatever it is worth, has been Kim's show from the beginning to the end. Trump just let it happen.

If you have been a Fox viewer of opinion shows like The Five, Outnumbered, Hannity, Carlson and The Greg Gutfeld show — ArguingWAristotleTiff

...then you are beyond all hope.

If there is objective morality, then equal interests per life time for each sentient being should be the aim to achieve. — Atheer

1. How do you define "objective morality," and why?

2. What does "equal interests per life time" mean?

Hey, you’re making a lot of the same points I would make if I held your view. What’s your background? — Fool

Oh, my educational background is nothing spectacular. As far as physics, I only have a BA and some graduate courses from many years ago. So don't take my pronouncements too seriously ;)

It’s smart to distinguish frequency shifting from different sources. It’s standardly used to measure front-back motion within our own solar system, where inflation is negligible. The flip side is that the mechanics describing motion throughout the galaxy will entail increasingly precise frequency shifts. — Fool

Yes, we can and do observe redshift from peculiar motions of objects within our cosmic neighborhood. But that doesn't help with detecting cosmological redshift - on the contrary. Even ignoring the other issue to which I'll return in a moment, all this back-and-forth motion creates a background from which it would problematic to extract a tiny effect, even if it actually was systematic. (How would you distinguish a tiny systematic bias in the data from noise? Noise doesn't have to be perfectly unbiased!) But more to the point, bodies within our galaxy are gravitationally bound, and their free-fall towards each other counteracts metric expansion of space.

Could there be other ways by which we could predict and perhaps even detect expansion of space? Well, as I mentioned earlier, expansion was in Einstein's equations - in their (arguably) simpler, more natural form - right from the beginning, so that in order to remove that expansion, a term had to be added. So perhaps even without any observations to prompt it, the hypothesis would have already been on the table. And whether it would have been dismissed, as Einstein did before Hubble's discovery, or taken seriously, is a matter of historical speculation. To take another example from recent history, there is a sizable group of physicists that take the theoretical prediction of quantum "many worlds" seriously - simply because they seem to be right there in the equations, and it takes additional, non-empirical postulations to get rid of them. Some empirically inaccessible predictions of cosmological theories, such as "bubble universes," are also justified by the fact that they are inevitable consequences of a theory that is, or might be otherwise well-supported by observation.

Are there possible experimental ways of detecting metric expansion of space, other than through cosmological redshift? Perhaps you are right, and there could be alternative paths to discovery. But here I would rather defer to the experts. I don't think much about Krauss's philosophizing, but on this question he is undoubtedly an authority that ought to be taken seriously. He may be wrong, but it is far more likely for you or I to be wrong about this than it is for him.

So I'll meet you half-way: A civilization with no access to the same observations that we have might nevertheless entertain theories that predict those same observations, and might even in some cases find strong indirect support for such predictions. But this is by no means guaranteed. There is no good reason to think that scientific theories inevitably converge towards some fixed final shape. The less data we have in some area, the more uncertainty there is about theory choice. Moreover, observer selection effects can bias and lead us away from the "truth" (for lack of a better word).

I'm suggesting this evidence may not be necessary. Even if we had to rely on red or blue-shifted light, Doppler Effects within our own galaxy may compel the same hypothesis - not that I'm convinced we could only discover the expansion of space through shifted light. — Fool

The thing is, you need much larger scales in order to detect redshifting due to expanding space. On the scale of a galaxy gravitational attraction overcomes this effect. It's not just that the effect would be too minute to extract from the background (though it probably would), it is that gravity keeps objects within the galaxy together, so the effect is nonexistent.

The point is the mathematical nature of physics connects seemingly unrelated phenomena in unforeseeable ways, so it seems premature to rule out all possible evidence. — Fool

I think you are underestimating the underdetermination of theory by evidence in general, and the autonomy of physical theories at different scales/energies in particular.

From the perspective of theory, expanding space is just a parameter in Einstein's field equations. It is altogether absent in quantum physics, or any other theory that deals with scales much smaller than cosmological. Initially, when he didn't know any better, Einstein introduced his cosmological constant in order to make space static, rather than expanding. The constant was dropped, and then reintroduced again in response to further astronomical observations.

But what if such observations were not available? What form of the equations would we have ended up with? On the one hand, a static universe just seems like a simpler assumption. If it is not static, then is it expanding? Contracting? At what rate? On the other hand, equations would have been simpler without the constant. This dilemma aptly illustrates the difficulty of theory choice under insufficient evidence. Even if we are comfortable with using parsimony as a deciding factor, just how it should be applied isn't so obvious.

From the point of view of parsimony, we ended up with the worst of both worlds: we have the cosmological constant in the field equations, and the universe is expanding. Of course, plentiful evidence trumps parsimony, elegance, or any other such a priori considerations. But if we did not have this evidence, why would we have chosen such an inelegant, overcomplicated theory?

Our current theory of the fundamental forces tells us which structures/substances can exist, under what conditions they can come about and how long they would take to form. — Fool

Sure, theories at different scales (effective field theories) are not completely autonomous: they can constrain one another.

So no, the current situation (observable galaxies or not) isn't consistent with the universe coming about last Thursday. — Fool

Oh no, nothing can rule out Last Thursdayism :) This is where other, non-empirical considerations come in.

I heard Krauss say that, and it annoyed me. i’m sure they’ll eventually discover space is expanding and then put 2 and 2 together. — Fool

How would they figure that out? Expanding space is validated by precisely the sort of astronomical observations that would not be available in that hypothetical future.

Physics is so mathematical that laws governing nuclear chemistry have cosmological implications. — Fool

Oh no they don't. You can have all of nuclear chemistry and a static universe, no problem.

I have used this quote to argue with cosmologists over the years. We may live in a special time but how can you know if all the evidence of the universe's creation is still available? — Codger

The universe may have popped into existence last Thursday, complete with all of the evidence that points to a much greater age. How would you ever know that this is not the case?

This is not cosmology, this is just sophomoric philosophy.

As @LD Saunders notes, the quote has nothing to say about math. It is about empirical knowledge, which is in all cases circumscribed by available evidence. Here you have a rather dramatic example, but one can think of countless ordinary examples that illustrate the same point. How many coins do I have in my pockets right now? I can answer this question by taking them out and counting, while you have no way of knowing whether I even have pockets.

Speaking of cosmology and astronomy, our present situation is only relatively privileged. Yes, we can say with great confidence that there are other stars and galaxies and all sorts of other celestial bodies and structures. But as we probe further, our knowledge becomes less and less certain, until it dissolves into guessing. The large-scale topology of the universe; the universe "before" the Big Bang - we may never have more than speculative answers, and not because we are not clever enough, but because we just don't have the data necessary to test our theories.

Not, of course, that this in any way addresses the fact that it remains a case of appealing to the unexplained to explain the unexplained. — StreetlightX

P1. Quantum mechanics is mysterious.
P2. Consciousness is mysterious.
C. The two have to be related somehow.

You can't argue with the logic!

It's interesting to note though just how philosophical Einstein's thinking was throughout his work on relativity and quantum physics It wasn't just "let's find a mathematical model that fits the data better," which would have probably ended up with epicycles rather than with a radically new (and at the same time old as Galileo!) theory.

Fisrt up I want to talk about one role philosophy has in the progress of science - with a view to discovering others. — Kym

Well, I am still not seeing much of that in what you have posted. Unless you think that "Hey, here is a naive layman question about some complex science" constitutes an example of such a contribution. Those philosophers of science who are serious about their subject usually have a decent grasp on the science. If you are interested, I suggest you look at some actual examples. Perhaps flip through a philosophy of science journal, or look at some papers available online. Here is, for instance, a selection of philosophical papers about General Relativity on Philpapers.

I am not sure what it is that you want to talk about. Is it scientific puzzles and paradoxes in general? The three examples that you gave really don't have much in common, even under that broad topic.

Your black hole question most likely belongs to the category of layman misunderstandings of complex science. I am not saying this from a position of expertise - my own physics background is insufficient to answer your question - but from the position of common sense. An elementary question like that, if it was a genuine puzzle, surely wouldn't have gone unnoticed. Given your almost total ignorance of this difficult topic, the surest way to find an answer would be to learn more about it. Which is why you ought not assume right away that you have stumbled upon some paradigm-shattering paradox and, if investing years into the study of math and physics doesn't sound promising, at least go ask your question on a friendly science board, where someone might be able to give you a lies-for-children version of the answer.

Zeno's problems are more of a philosophical topic, and I encourage you to read the rest of the excellent SEP entry.

The Black Body Problem, aka the Ultraviolet Catastrophe doesn't really have much to do with Zeno. Whereas Zeno's problems, on their most generous reading, come down to the general metaphysical issue of super-tasks (performing an infinite number of actions in a finite interval of time), the black body problem was an indication of an inconsistency of a particular physical model. It did not go unnoticed and was not ignored. Physicists at the time recognized it as a genuine problem, but what no one realized was just how radical the resolution of the problem would be.

That's a fair point. I guess I am just not very serious about ontology: I am more interested to know what the world is like than what "stuff" it is made from or what "things" it ought to be parsed into - which puts me more on the side of instrumentalists and pragmatists. But I am also on the side of common sense and natural language in wanting to say that yes, there are chairs and cats and temperature and charge. That's just what "existence" means to us.

That seems question begging about how you would define "real" here. How does it not wind up sounding idealist or subjective - that is, anti-realist? — apokrisis

Well, I am not too concerned with how this sounds, but what question is being begged here?

And an even greater difficulty. The least action principle is an example of how science does appear to discover a unity, rather than a pluralism, at the deepest ontic level. — apokrisis

That to me suggests a structural relationship between theories. One is tempted to conclude that what accounts for this common trope is that in their different ways these theories all get a hold on the same truth. But one should always keep a bit of wary skepticism and not be totally seduced by theoretical elegance. That way lies dogmatism.

Science tends lead people to one of these views:

1. Reductionism: There is one true ontology (usually assumed to be something like that of the Standard Model of particle physics), while the ontologies of other sciences are useful fictions. This is mostly favored by physicists and others with "physics envy" (like chemists ;)).
2. Instrumentalism: All ontologies are useful fictions.

I would also add

3. Pluralism: Ontologies are dependent on theories that posit them, and they are all real just to the extent to which their respective theories are taken seriously.

I clicked on your thread, and spent maybe 10 minutes on the first page of Google results (most of which are this guy's sites or sites affiliated with him). That's about as much time as this crank warrants, sorry.

With titles like "Why materialism is baloney" I am not surprised that he is not taken seriously.

Yeah, sorry :blush: E. Nagel.