# My philosophy teacher

Pythagorean
Gold Member
What's "the scientific realism debate"?
Scientific realism is central to the philosophy of science. Spend some time on google.

atyy
Hehe. You're the first in this thread who's made that assertion. In what sense is it not valid?
Newton's law of gravity has been falsified by classical GR.

Classical GR is not consistent with QM, so the theory is not even wrong.

Maybe she was talking about string theory?

One thing we know for sure that will remain valid in a 100 years is the TOE - because if it isn't, it's not the TOE! Caveat - unless time exists only up till 99 years from now. The other possible attack on the teacher's statement is the assumption that probability exists - is she a frequentist or a Bayesian?

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Scientific realism is central to the philosophy of science. Spend some time on google.
I'm not interested in anything called "The Philosophy of Science". I like science because it makes engineering hella easier.

Newton's law of gravity has been falsified by classical GR.
I've never heard this asserted. What I hear is more along these lines:

General relativity reduces to Newtonian gravity in the limit of small potential and low velocities, so Newton's law of gravitation is often said to be the low-gravity limit of general relativity.
http://en.wikipedia.org/wiki/Newton's_law_of_universal_gravitation

Pythagorean
Gold Member
I'm not interested in anything called "The Philosophy of Science".
I can tell by the way you avoided spending time/energy in this thread

I can tell by the way you avoided spending time/energy in this thread
I enjoy rigorous logic. "Philosophy" is when you smoke some hash with your buddy, look at the stars and proclaim "Dude! Do you realize that in 10,000 years the law of Universal Gravitation might not be valid?"

"WHOAA! Shut up man! That's TOOO heavy!"

atyy
I've never heard this asserted. What I hear is more along these lines:

http://en.wikipedia.org/wiki/Newton's_law_of_universal_gravitation
That Newton's gravity is only the weak field slow motion limit of GR means that Newton's gravity has been falsified (doesn't have to be that strong - Newtonian gravity already gets mercury wrong, while GR gets it right).

General relativity reduces to Newtonian gravity in the limit of small potential and low velocities, so Newton's law of gravitation is often said to be the low-gravity limit of general relativity.
In other words, Newton is wrong in all gravity fields. The lower the gravity, the less wrong.

Actually, that's a wiki quote, not a zooby quote.

I'm not interested in anything called "The Philosophy of Science". I like science because it makes engineering hella easier.
You have company.
R. Feynman said:
Philosophy of science is about as useful to scientists as ornithology is to birds.
wikiquote (and therefor unreliable)

In other words, Newton is wrong in all gravity fields. The lower the gravity, the less wrong.
I don't completely get this. Newton set out to prove gravity was universal: that all heavenly bodies had gravity. This, he did, by a mountain of geometric proofs that showed that, if they did, we'd see the orbits we actually do see (he didn't know about Mercury, and I don't see how his failure to predict the Mercury thingy invalidates the theory that all heavenly bodies have gravity.) To say he's wrong or has been falsified should mean we've found some masses out there that don't have gravity.

Einstein was in a position to formulate a much more "meta" conception of gravity, but I don't see it as 'invalidating' Newton. "Superseding" Newton, is acceptible:

Newton's law has since been superseded by Einstein's theory of general relativity, but it continues to be used as an excellent approximation of the effects of gravity. Relativity is required only when there is a need for extreme precision, or when dealing with gravitation for extremely massive and dense objects.
http://en.wikipedia.org/wiki/Newton's_law_of_universal_gravitation

To say he's been "falsified" or 'invalidated" seems to misunderstand the point of his theory.

“If you thought that science was certain - well, that is just an error on your part." R.Feynman
To every purpose, there is a Feynman quote.

To every purpose, there is a Feynman quote.

I think you are misunderstanding what people are saying to you in this thread(incl. the philosophy teacher, who i don't perceive as attacking valid scientific inferences, but mistaking tentative but valid to the best of our knowledge conclusions for all encompassing truths). DaveC makes good points(as ever)

Newton proposed three postulates. Using those postulates, he makes numerical predictions on the outcomes of experiments. The numbers don't match experiment. What more do you want to falsify a theory?

I think you are misunderstanding what people are saying to you in this thread(incl. the philosophy teacher, who i don't perceive as attacking valid scientific inferences, but mistaking tentative but valid to the best of our knowledge conclusions for all encompassing truths). DaveC makes good points(as ever)
It's perfectly OK with me to suggest I'm mistaken, but explain what you think Dave is saying that I don't understand, and rephrase what you said about what the teacher is saying. I couldn't make heads or tails of it the way you put it.

Newton proposed three postulates. Using those postulates, he makes numerical predictions on the outcomes of experiments. The numbers don't match experiment. What more do you want to falsify a theory?
I would want it not to constitute" an excellent approximation of the effects of gravity". That would make it much clearer.

I would want it not to constitute" an excellent approximation of the effects of gravity". That would make it much clearer.
Have you seen that video of Feynman where he sweeps his hands as if calling a runner out at home plate?

chiro
I think noting the point that science is largely an inductive endeavor is important.

It has worked for us in great ways like with gravity and electro-magnetism and maybe for this reason it has created a dangerous precedent to use induction without necessary caution.

None the less, if we take philosophers advice but maintain a low kind of 'philosophic paranoia' then I think the scientists will still do the amazing things they do and still minimize overconfidence and arrogance.

Have you seen that video of Feynman where he sweeps his hands as if calling a runner out at home plate?
No, I saw the one where he sweeps equal areas in equal times.

If we don't know gravity (or anything at the same fundamental level) is going to be valid in 10,000 years, then we don't know it will be valid in 10 minutes, either. Strictly speaking, we don't.

It's always easier to predict outcomes that lie 10 min from now than ones that lie 10 000 years away. The latter would be definitely more tentative and much more likely to be wrong in so many ways. You seem to extrapolating scientific conclusions to truths and extending them unreasonably far, which is what the teacher appears to be fighting against.

Not wishing to be a science zealot I can, therefore, recommend this teacher jump off a cliff at the first opportunity. Because I take her point: I have no definite means of knowing if gravity will be valid when she does.

That's not her point, you are arguing against your own interpretation of her words. Both scientific overconfidence and arrogance and its philosophical counterpart - "it's just a theory" are signs of immaturity(IMO).

We don't know if the law of universal gravity holds. We assume it does(we don't have the means to verify in all corners of the universe, but only make limited observations and reach conclusions based on the observations and the part of the visible universe in question)

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No, I saw the one where he sweeps equal areas in equal times.
R. Feynman said:
If it disagrees with experiment, it's wrong. That's all there is to it.
If your theory makes both correct predictions and incorrect ones, then it's just as falsified as if it only made incorrect ones. This principle has been applied to the phlogiston theory which also got some things right.

In practical terms, I think scientists would be reluctant to abandon a falsified theory if there were no better theory to take its place. However, this is not the case with Newton. Whenever Newton gets it right, so does Einstein. But when Newton gets it wrong, Einstein gets it right. Game over. The only thing left is to speculate whether in the future, Einstein may in his turn be falsified. In addition to philosophical reasons, I think there are theoretical reasons to expect it may. As I said before, there is currently no consistent theory including both gravity and quantum physics. Something's gotta give.

Pythagorean
Gold Member
I enjoy rigorous logic. "Philosophy" is when you smoke some hash with your buddy, look at the stars and proclaim "Dude! Do you realize that in 10,000 years the law of Universal Gravitation might not be valid?"

"WHOAA! Shut up man! That's TOOO heavy!"
Arrogance...

chiro
Arrogance...
While he clearly is making a mockery, some philosophers can be too far out there to be practical (they might actually be technically correct or make a good point, but again its what I refer to as 'too much paranoia').

If you end up getting stuck in an 'analysis paralysis' then that doesn't do anyone any good. Finding the sweet spot between 'arrogance' and 'analysis paralysis' is something that will probably be debated for a very long time.

Pythagorean
Gold Member
Some (enter group here) can always be too far out.

fuzzyfelt
Gold Member
One thing we know for sure that will remain valid in a 100 years is the TOE - because if it isn't, it's not the TOE! Caveat - unless time exists only up till 99 years from now. The other possible attack on the teacher's statement is the assumption that probability exists - is she a frequentist or a Bayesian?
Interesting!

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