There are relativists of all kinds in philosophy, thoughts I do think they’re generally wrong and counter to the spirit of philosophy itself.

Relativity in physics though is not relativist in that sense. There is still an objective reality, it’s just that certain facets of it are relative to other things. It’s like how realizing that the world is round means that “down” is relative, but it doesn’t mean there are no objective directions at all. Relativity in physics is like that: lengths and durations and so on vary from observer to observer, but there are still objective physical realities underlying those things, which all observers can agree upon.

Indeed, the Principle of Relativity has more general application. It says simply that the laws of physics are the same for all observers. In other words, and contrary to popular simplifications, it says that what is true will be true for all observers.

Going on past experience, that comment will help this thread get at least another fifty posts, perhaps more.

You're welcome.

In other words, and contrary to popular simplifications, it says that what is true will be true for all observers. — Banno

So much so that Einstein thought he should have named the theory of relativity the theory of invariance instead.

As for the OP: there is no such thing as 'general philosophy', and even if there was, what reason would there be that SR would contradict it?

what is true will be true for all observers — Banno

The length of a moving rod? The time on a clock? The velocity of a moving body? These are all observables; they are not invariant.

Invariant laws of physics was the project of relativity (the second postulate being an ought) and this led to a weakening of what was thought invariant (in terms of categories... obviously a strengthening in terms of robustness of theory). Energy is no longer invariant, but (energy, momentum) is. Charge is no longer invariant but (charge, current) is. But these are counterintuitive as observables.

Relativity is specific to laws of physics in the same way that natural selection is specific to terrestrial biology. The important thing about both is that, in science at least, they destroyed our reliance on intuitions, on biases toward imposing on the world the character of our own evolved cognitive frameworks.

It is counterintuitive that there is no special frame which pins down the chronology of two distant events just as it is counterintuitive that death creates species. Nonetheless these are true, and they act as a lesson to be aware of the sources of our assumptions and to avoid the trap of valuing the attractiveness of an idea. The judge here is empirical evidence, and that evidence demands that we forego our intuitions and proclivities.

Philosophy is not empirical and has no such judge. If Platonism appeals to you, be a Platonist. If dualism appeals to you, be a dualist. This frees up philosophy somewhat but also confines it. Our intuitions and proclivities are not demolished, and we're doomed to make the same errors of bias as ever.

What philosophy could learn from relativity is not to impose human psychological frameworks for understanding the world on the world itself, that the ways we think and what we think important are not objectively useful. It should learn that what is true for me is not necessarily true for you, that while there might be a direct map from my experience to yours, one is not necessarily true and the other false.

This should be especially considered when dealing with concepts that are clearly cultural, i.e. localised.

The length of a moving rod? The time on a clock? The velocity of a moving body? These are all observables; they are not invariant. — Kenosha Kid

You know the answer to that. Observer A will see a rod of length l. Observer B will see a rod of length l'. But observer A will also see that observer B will see a rod of length l'; and observer B will see that observer A will see a rod of length l. They do not disagree as to the facts.

For the rest, yes.

Well said.

Philosophical versions of invariate truth are inevitably introduced as "There is an invariate truth", and equally inevitably appended later with "...and whatever seems to me to be the case is what it is".

That there exists an invariate state of affairs is a matter of interest almost solely to physics and this is entirely because theories like general relativity show that whatever such invariate truth actually is, our intuitive beliefs are almost certainly not it.

Observer A will see a rod of length l. Observer B will see a rod of length l'. But observer A will also see that observer B will see a rod of length l'; and observer B will see that observer A will see a rod of length l. They do not disagree as to the facts. — Banno

Only if they've been previously apprised of relativity theory. Otherwise A is more likely to consider B to be lying, mistaken, defective and vice versa.

Yep. And A would be wrong.

invariance — StreetlightX

...now look what you have done, introducing that word...

Yep. And A wold be wrong. — Banno

Your assertion was that they wouldn't disagree as to the facts, not that neither of them would be wrong. A would indeed be wrong, but only by virtue of accepting that something seeming to them to be the case (no matter how strongly so) is no indicator that it actually is the case. The whole project of relativism in philosophy in a nutshell.

...that they wouldn't disagree as to the facts, — Isaac

No, I said

what is true will be true for all observers. — Banno

What they agree or disagree to is irrelevant.

But then, you think truth and belief are the very same, so I can see why this is a problem for you. :razz:

What they agree or disagree to is irrelevant. — Banno

What they agree or disagree to is the entirety of human belief, it's the most relevant, and arguably, the only, subject matter in philosophy. As I said, the invariate truth of a physical reality is a subject for physics and rarely coincides with the beliefs we discuss as matters of philosophy - morality, conceptual schemes, meaning, ontological commitments...

You may well baulk at a conflation of truth and belief (notwithstanding that your caricature is, obviously, oversimplified), but the point I'm making here is that your notion of 'truth' as being that which is invariate between observers is disingenuous relative to your actual use of the word (which invariably means 'that we really strongly seems to me to be the case').

Have what is 'true' mean 'that which is invariate between observers' if you like, I'm cosmopolitan about language, just accept that you can then cannot make use of it in virtually all the cases you'd normally do so.

"Is it true that the length of this rod is five metres?"

"No, it's only true that it appears to me at my momentum to be five metres but to a different observer it would appear a different length"

Good luck with that.

What philosophy could learn from relativity is not to impose human psychological frameworks for understanding the world on the world itself, that the ways we think and what we think important are not objectively useful. It should learn that what is true for me is not necessarily true for you, that while there might be a direct map from my experience to yours, one is not necessarily true and the other false. — Kenosha Kid

This wording is not great, I apologise. Obviously tons of philosophers have greked this, and some well before physicists did (e.g. Kant). What I meant was that, in the sciences, paradigm shifts like Darwinism and relativity a) can't be ignored (empiricism), and b) seed new ways of thinking in other fields. Darwinism, for instance, has had a huge impact on cosmology despite having little in common.

Whereas frameworks that precede these seem to have a longer shelf-life in philosophy. For instance, I think that most physicists would probably reject moral objectivism, whereas most philosophers I've spoken to believe it is true, and I do think that relativity, while having nothing to do with morality, did impact how we think generally about objective frameworks. Like I say, philosophers got there first, but the effects seem less pervasive.

Wait till I say that this is an objective relativism.




Now enjoy the show.

@SophistiCat gave me this reference in a thread a while ago. It talks about what philosophy can learn from special relativity.

I don't think that's entirely true. One book on philosophy, actually critical thinking but critical thinking is the meat-and-potatoes of philosophy, I read went out of its way to point out that looking at issues from all sides - all perspectives - will give a more complete, truer, picture of reality. That's relativity, right?

That said, philosophy has the notion of objective truth, truth that doesn't, shouldn't, change with perspective and oddly, many of these objective truths are intimately tied to physical properties like mass and spatial extension which, Einstein's theory demonstrates, are relative. It looks like philosophical objectivity, if the best examples of it are the physical properties mass and spatial extension, is nothing more than a fairy tale.

Then there's the matter of personal bias. Bringing your own personal perspective makes for a fine contribution in a group discussion but what we have to watch out for is biases/prejudices which will, according to the experts, distort the truth in such a way that it seems pleasing to your eyes but you know for a fact, all that glitters is not gold. Objectivity then is a way of avoiding this pitfall that waits with infinite patience for the unwary traveler. If by relativity in philosophy you mean to include even ]personal bias then it's something undesirable and thus must be steered clear off.

For instance, I think that most physicists would probably reject moral objectivism, whereas most philosophers I've spoken to believe it is true, and I do think that relativity, while having nothing to do with morality, did impact how we think generally about objective frameworks. — Kenosha Kid

Crazy religious nuts object to relativity in physics because they think it will lead to moral relativism. Don’t give them any ammo.

Crazy religious nuts object to relativity in physics because they think it will lead to moral relativism. Don’t give them any ammo. — Pfhorrest

It's just an impression. I've had a hard time finding any data on this at all. I guess it's an odd question to ask someone.

Relativity (and quantum observtion) is fully compatible with Aristotle's understanding of reality. He tells us that continuous quantity is measurable., and that time is the measure of change according to before and after. Because quantity is measurable, quantitative reality not an actual number pre-existing measurement, but something a measuring process can be applied to, to produce an actual number. If we use a different measuring process, say measuring in a different frame of reference, then we have every reason to think we will get a different measure number.

The same applies to quantum measurements. Their results do not pre-exist the measuring process either, but are the result of the interaction between the system we are measuring, and our measuring apparatus.