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Physicists and Philosophers Debate the Boundaries of Science

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Re: Physicists and Philosophers Debate the Boundaries of Science

#101

Earlier quoted context omitted.

I didn't claim it did - all I said is that this gives Occams Razor as an asymptotic law. Intuitively, I'm claiming: Lim_{complexity -> infinity} P(theory having fixed complexity) = 0 Stated more precisely, fix a prior distribution, then for any epsilon > 0, I can find a complexity cutoff C (which depends on the prior) so that P(any theory with complexity > C being true) This doesn't mean that P(theory|complexity) is…

Here's an argument that runs completely parallel: jwmerrill's razor: points in the plane should be considered to be close to the origin unless there is evidence otherwise. Is this a reasonable law? As reasonable as Occam's razor? I think probably not, but I don't have a strong opinion. One interesting thing to note is that the law doesn't say where the origin is (similarly, Occam's razor is vague about what exactly i…

A better statement of jwmerril's razor: points drawn from a probability distribution have a higher likelihood than points coming from far away.

I don't really know why you don't think that the asymptotic forms are evidence in favor of this - a prototypical probability distribution on the real line is a bump somewhere with a decaying tail. And that "somewhere" is far closer to the origin than points out in some arbitrarily distant tail.

Now obviously if you want to make stronger claims about a specific origin, you'll need to specify a particular probability distribution, and justify why that's the right one. I agree that a non-asymptotic Occams razor is an additional assumption.

But you also get pretty far with the asymptotic theory. Consider a theory of "green" as compared to a theory of "bleen" (namely that green turns to blue after some time T). You have a prior with some probability that only green exists (say 50%), and also a 50% chance that green turns to blue after some time T. But now you have a continuous distribution over T.

Now suppose you want to make a prediction - e.g., H = "the grass will be green, not blue, at t=50". When you compute a posterior, you reject all values of T 50 actually yield the same prediction as "only green exists". So the only way you can get a prediction of blue at time 50 is if 0 I do in fact hold the view that Bayesian probability is a consistent theory of the scientific method, and also of how humans should update their beliefs when new evidence is gathered.

(Minor nit: your continuous asymptotic form isn't slightly wrong for this purpose, f(x) need not approach zero. Counterexample: f(x) = 1 for x \in [1, 1+2^{-1}], [2, 2+2^{-2}], etc, f(x) = 0 elsewhere. That integrates out to 1/2 + 1/4 + ... = 1, but lim_{x -> \infty} f(x) doesn't exist.)

[I'm also a bit surprised you are being so heavily downvoted. I don't think you are right, but you are hardly so crazily wrong that you should be greyed out.]

Re: Physicists and Philosophers Debate the Boundaries of Science

#102
post #73

Earlier quoted context omitted.

What does physics have to do with Cantor.

To get to Cantor's theories you have to accept his concept of a "completed infinity". This implies that infinity is a metaphysical concept, i.e. that infinity really exists in the universe. For example, do you believe that black holes are really infinite density or does an infinite property indicate a breakdown in the equations or theory, i.e. infinity is an epistemological concept. Modern physics is not consistent o…

> i.e. that infinity really exists in the universe.

I don't see why this has to follow.

Re: Physicists and Philosophers Debate the Boundaries of Science

#103
post #30
post #15

Physics used to be "hard science" - if it wasn't testable, it wasn't meaningful. Physicists used to look down on other sciences for that reason. This article shows how much worse things have become. Nobody can figure out a way to test string theory. In cosmology, you can only observe, not experiment. As the article points out, the big questions are out of reach for scaling reasons. Trying to fix the problem through w…

> Physics used to be "hard science" - Physics is still a hard science. However, the edges of physics are difficult to test. > In cosmology, you can only observe, not experiment Saying that is like saying "we don't know evolution is true, because we don't see new species evolve every day". It's a naive approach to science. In both cases, you can use theories to make predictions about new things to look for. e.g. http:…

There are two types of science that are fundamentally very different to each other; observation science and experimental science. The base thinking of the two types of science are very different and even the people drawn to each type are quite different.

Physics is interesting in that both types of science are successful, where in say molecular biology or geology only one type dominates.

Re: Physicists and Philosophers Debate the Boundaries of Science

#104
post #82
post #34

We had a rush of scientific breakthroughs 100 years ago. I believe we will have more. That experimentation in physics has slowed down to 18th century levels doesn't mean science is over, it just means the low-hanging fruit is over and we will have to continue slogging through theory before we discover new experiments. Science has always relied on philosophy for its underlying direction, it's just obvious again. It to…

> It took 2040 years before science/math could answer Zeno's paradoxes. And that's only if we assume calculus answered them. Which is not the absolute consensus of logicians/mathematicians. Many seem to believe they are simply about limits and that's all, but they may also point to a more fundamental aspect of reality. E.g. from Wiki: A suggested problem with using calculus to try to solve Zeno's paradoxes is that th…

>Imagine that Achilles notes the position ... and so on

If in logic you assume/imagine something, and reach a contradiction, then your reaction should be to reject that assumption.

In this case we reach the conclusion that Achilles cannot note all the positions.

Re: Physicists and Philosophers Debate the Boundaries of Science

#105
post #73

Earlier quoted context omitted.

To get to Cantor's theories you have to accept his concept of a "completed infinity". This implies that infinity is a metaphysical concept, i.e. that infinity really exists in the universe. For example, do you believe that black holes are really infinite density or does an infinite property indicate a breakdown in the equations or theory, i.e. infinity is an epistemological concept. Modern physics is not consistent o…

> i.e. that infinity really exists in the universe. I don't see why this has to follow.

[deleted]

Re: Physicists and Philosophers Debate the Boundaries of Science

#106
post #48

This crisis in Physics makes me happier than anyone can know. It signals the end of the dominance of Kantian philosophy in Physics. Mach's principle (Einstein's polestar), Popperian falsifiability, Cantor's paradise of infinity (as described by Hilbert) and all other derivatives of Kant are the dead-end of a false metaphysics and epistemology. We do indeed, live in interesting (or depending on your worldview, dangero…

What's the (an) alternative?

Nothing I say will convince you.

Re: Physicists and Philosophers Debate the Boundaries of Science

#107
post #99
post #96

Earlier quoted context omitted.

Japan's surrender had absolutely nothing to do with the bomb. And why does everyone think that without Einstein we would somehow enter a 100 year long dark age?

> " And why does everyone think that without Einstein we would somehow enter a 100 year long dark age? " He said "without Einstein's theories ". Physics would probably have progressed about the same, albeit set back by a bit without the man himself, but all those technologies would still have been dependent on someone doing what Einstein did.

Like Hilbert.

Re: Physicists and Philosophers Debate the Boundaries of Science

#108
One of the things that has struck me for a long time about social sciences (and sciences where, in general, the evidence is based on stochastic processes) is that the underlying philosophy of logic is modern symbolic (aka Boolean).

The biggest problem there is that hypotheses have no underlying mechanism to make sure that the potential cause and effect are semantically related.

If p then q seems innocent enough. It probably seems even more innocent (or at least more simple) than All men are mortal Socrates is a man Socrates is therefore a mortal.

Because the required relationships in a syllogistic model can become a bit complicated.

I started off in this realm as a Philosophy major studying mostly Aristotelian models of deductive reasoning. It was mostly for kicks because I was a violinist at the time and needed a break from my music theory courses.

But when I got into the market research industry and started writing statistical software, I found serious problems with assumptions everywhere I looked. It seemed to me that there's a real problem with the way people with informal or introductory experience dealt with statistical results, with the relationship between null and alternative hypotheses, and with the evidence generated by sampling processes.

This is probably largely irrelevant to high-level Physicists, but I think it's at least partly relevant when we talk about what is and isn't falsifiable.

There's a comment in the piece where a guy says that Astrology is falsifiable, so we know that shouldn't be the only criteria for something to count as Science. I think he's on to something there because I think the fundamental hypothesis of Astrology is so far out of whack that it shouldn't have been considered.

There's nothing behind astrology that's any better than a bad if p then q statement. But we have no way of evaluating these by form. One can simple say, "If the grass is green, then the moon is made of blue cheese." This is formally a valid statement.

The problem I encounter many times (anecdotally, of course) is that people don't treat this statement as a material implication. They treat it as a logical conjunct. So that seems somewhat safe in the grass/moon example. They make the mistake of thinking of it as simply as, "If the grass is green AND the moon is made of blue cheese . . ." Well, that's clearly false. So why bother?

But a material implication has consequences. You can flip it around and say (by axiom) that if p then q then !q implies !p. I can assert that green grass => blue cheese moon. And if you accept that as valid, you can likewise assert that !blue cheese moon => !green grass.

It's easy to see the flaws in this contrived example, but it's often very difficult to see these problems in realistic examples when you are looking at effect sizes in medicine, or changes in advertising techniques, or samples from thermometers, or the kinds of things that I have no knowledge of in theoretical Physics.

It's often very difficult to assess when a scientific study has any realistic relationship between a null and alternative hypothesis. It would be nice if it were all statistically about whether or not these two numbers are the same or different, but that's frequently not the case.

I think the idea is correct, that we do need Philosophers to come up with a better system. Even something as simple as "The subject of a material implication must be included in the predicate of the material implication." might be a good start. Although it's woefully naive.

It would be kind of interesting to see people testing hypothesis in the scientific world that were formulated as syllogisms.

i.e., based on studies x, y, and z we can make the following claims: all (or some--doesn't matter. Most "some" claims can be reduced to a subset of "all" claims) x are y This study shows that z is x Therefore z is y

Is it limiting and problematic? Of course. Where do new categories happen?

Well, there are negations. You can prove that phenomenon z is not a member of previously known phenomena and is therefore something else.

While I think a great many of people sort of feel this way about stuff, I think there's a reason to codify it formally. Because so many people don't think very clearly about these things in aggregate.

It seems kind of ugly. But it would be an improvement over what we have now, which is basically a free-for-all in certain realms of science, where any sufficiently complex idea is grounds for further research, even when the possibilities of proof are non-existent. I say that more to the social sciences than I do the theoretical physicists of the world, so perhaps I'm off point here.

But my general idea is that, yes, philosophy can and should step it up a bit.

Re: Physicists and Philosophers Debate the Boundaries of Science

#109

One of the things that has struck me for a long time about social sciences (and sciences where, in general, the evidence is based on stochastic processes) is that the underlying philosophy of logic is modern symbolic (aka Boolean). The biggest problem there is that hypotheses have no underlying mechanism to make sure that the potential cause and effect are semantically related. If p then q seems innocent enough. It p…

Just as a rough outline for how this could work, consider the following syllogism:

All possible interactions are explained by Einstein's Theory of Relativity.

This particular observation is not explained by Einstein.

Therefore this must have a different explanation.

This gives us a testable proposition by definition.

This gives us proposition 2 to focus on and rebut, if we can.

Generally, I think this is how good science works, but it's not codified. An additional benefit to this concept is that if stored in a central location, it gives us a graph network to deal with and search through.

And it gives us a tree to look at. So anything invalidated higher up in the tree invalidates all of its branches.

Which is also good.

Re: Physicists and Philosophers Debate the Boundaries of Science

#110
post #79
post #45

Earlier quoted context omitted.

Just shows how sad academia is. Wouldn't be the first time I'm seeing those guys ponder endlessly on something other people say or do without bothering to really understand what those others are thinking and trying to achieve. BTW, is astrology actually falsifiable? I'm under impression that astrologists deliberately strive for unfalsifiability exactly to avoid falsification which could cast doubt on their wisdom.

> BTW, is astrology actually falsifiable? I'm under impression that astrologists deliberately strive for unfalsifiability exactly to avoid falsification which could cast doubt on their wisdom. It is. Just do the following experiment: Find, say, ten persons and an (or many) astrologists and let them create a horoscope (say, either a prognosis for the future or description of character traits) for these 10 persons, whe…

Have you heard about the Forer Effect? Horoscopes are written to be convincing to gullible readers.

http://skepdic.com/forer.html

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