Philosophy Discussion Forums

Andlan wrote: (Nested quote removed.)


Yes - I'm probably going to show my ignorance again here, but I thought angular momentum requires a force e.g. the spokes of a bicycle wheel direct a force into the center. Kinetic (e.g. Kepler) theories are explained by dynamic (e.g. Newton) ones are they not? This I guess is related to Steve's point about Einstein: (Nested quote removed.)

Yes, you would have to explain why objects fall more slowly at the equator than at the poles. I still think it strange that we will almost accept a spinning earth as irrefutable, but an orbiting earth as merely a point of view.

Andlan:

I thought angular momentum requires a force e.g. the spokes of a bicycle wheel direct a force into the center. Kinetic (e.g. Kepler) theories are explained by dynamic (e.g. Newton) ones are they not? This I guess is related to Steve's point about Einstein

I think, in Newtonian mechanics, angular momentum means rotation, and rotation means acceleration towards the centre of that rotation. And that means centripetal force. My understanding is that the Coriolis force can be understood (in Newtonian mechanics terms) in terms of conservation of angular momentum. The standard example of which being the speeding up of the rate of rotation of the ice-skater when she pulls in her arms.

The atmosphere is rotating with the Earth. When air at the equator moves towards the poles it moves closer to the Earth's axis of rotation (like the ice-skater pulling in her arms). That makes it speed up in its journey around that axis. So it "overtakes" the air that is now at the equator. So you get a circulation effect - cyclones and anticyclones.

The "Coriolis Force" is the same kind of thing as "Centrifugal Force". It is a "fictitious" force which appears when you place yourself in the rotating reference frame of the Earth. If you want to regard that rotating reference frame as the rest frame, you need to see these fictitious forces in the context of General Relativity - i.e. as Gravitational forces. My very rough understanding of that was what I said above.

Thanks for that clarification Steve - you plainly understand this a lot better than I do. So we need to explain these extra inertial forces in a geocentric universe, but that can perhaps be done (albeit with extreme difficulty)?

More simply, we can also treat this as a multi-body problem, in which the sun and the earth rotate about their common center of mass, but this is so close to the sun that it can be ignored forall intents and purposes. If we are trying to get to Mars perhaps it matters, but we should still tell our kids that earth goes round the sun, in case they are tempted by the alternative geocentric (perhaps more common sensical) model. If we increase the complexity and introduce the gravitational effect of other stars and galaxies and try to model the motion on a computer, I still doubt that any generated model will have the sun rotating around the earth.

One implication of saying that one model is equally as good as another seems to be that Ptolomeic epicycles should not have been thrown out completely after Galileo's observation of the phases of Venus. Perhaps we can agree that one model seems to be as good as another at describing (although perhaps not explaining or predicting - see Keen's comments?) what we observe. Perhaps we are also getting diverted by the assumption that the observations are fixed or just simply accumulating i.e. empiricism. You rightly noted that new evidence can lead to a radical overhaul of our theories, but it is also surely the case that what we observe (or focus on) is prompted by our theories. Priestley's observations conformed to his theory of phlogiston, and Lavoisier's to oxygen; but we could say that, in the end, oxygen conforms better with 'reality' since we would not now see phlogiston as an acceptable or useful model. Could this be a valid analogy to the centricism debate? If not, why not?

Andlan:

One implication of saying that one model is equally as good as another seems to be that Ptolomeic epicycles should not have been thrown out completely after Galileo's observation of the phases of Venus. Perhaps we can agree that one model seems to be as good as another at describing (although perhaps not explaining or predicting - see Keen's comments?) what we observe.

Yes, I don't think I would say one model is as good as the other. I think this more an exercise in what is possible, rather than what is preferable.

but it is also surely the case that what we observe (or focus on) is prompted by our theories.

Yes. Good point. We don't just "observe". We choose something to observe. How do we choose?

I think that's why I reckon that science starts with, or is related to, common sense. There seems to be a continuous iterative process of theory, or conjecture, following observation, following more conjecture. I think it's a kind of chicken and egg situation, going right back to childhood, both of the human race and of the individual human.

It seems to me that, from early childhood, we're doing experiments (though we wouldn't see it like that) to figure out how the world works. Obviously we don't all, or even mostly, go on to do formal science. But I still think formal science is a natural evolution from the continuous process of experimenting and learning (a.k.a. playing) that we've done since birth.

What do you reckon?

Yes, it is an ordinary choice in that sense. Science began when an solitary soul focussed their pure attention on the external world.

In the sense that it is a leap of the imagination, it is not ordinary - and as you acknowledged, Newton was a genius.

Andlan:

Yes I think the essence of Newton's genius (in the context of Gravity) was in recognizing a pattern, or a symmetry, between two superficially completely unrelated phenomena. (Orbits and falling objects).

Teh:

You believe something false: that there is a process of induction that works.

Popper, and other[s], have provided several definitive proofs that induction is false.

Steve3007:

Could you explain more? Please explain the definition of the word "works" in this context.

I'm still waiting for an answer.

Popper (it could be argued) simply renamed Induction. He did not remove it. He called it "corroboration". He (and Hume) pointed out that Induction cannot be logically justified. I.e. they pointed out that it cannot be logically deduced from more axiomatic principles. He then stuffed it into a box called "psychology" and pointed out that there are also lots of other ways that people dream up conjectures which have no obvious rational basis. They are often referred to by words like "inspiration".

But whether you call it "induction" or "corroboration" or "the tendancy to patterns in Nature" doesn't alter its utility; it doesn't stop it from working. A rose by any other name would smell as sweet.

Popper didn't refute induction. He simply hid it with awkward terminology.

Are you willing to discuss this, or will you just make another one-sentence assertion?

Steve3007 wrote:But whether you call it "induction" or "corroboration" or "the tendancy to patterns in Nature" doesn't alter its utility; it doesn't stop it from working. A rose by any other name would smell as sweet.

Popper didn't refute induction. He simply hid it with awkward terminology.

Are you willing to discuss this, or will you just make another one-sentence assertion?

I wasn't sure if induction was really within the terms of the OP - or should we just forget about that seeing as it's author has not made any recent comments?

I don't think it is a clear-cut case: induction or no induction. As a logical method, it seems to be disproved by black swans or turkeys at Xmas (can we not find some better examples?), but as intuitive pattern reading I believe it has merit as a way of describing how we come up with theories. As always, when you try to objectify human attributes such as intuition, you get into trouble. It is fashionable to assume that induction is sufficient to describe the scientifc method and go on to assert that it also justifies scientific theories via statistics and probability; something I think is profoundly misguided and damaging to the credibility of science. Science surely has a more determinate basis than this. If a doctor tells me I have a 75% chance of developing cancer based on historical case analysis, in reality I either have it or I don't, so it is fairly meaningless as a description of reality - although I don't deny it that it can give comfort to the patient to look at it like that.

You're right. Induction is probably not stictly relevant to this thread. I've noticed before that, for any given subject, there's usually a previous thread where it's already been discussed in at least some form. So that's probably true this time too. I'll go have a look and perhaps revive one from the dead!

---

I found one and revived it.

But, by way of finishing off, I'll just answer your point here:

It is fashionable to assume that induction is sufficient to describe the scientifc method and go on to assert that it also justifies scientific theories via statistics and probability; something I think is profoundly misguided and damaging to the credibility of science.

I have to admit that I have generally thought of induction as central to the process of manufacturing scientific theories and not really considered it to be damaging to the credibility of science. I always thought that the claim to have disposed of it was one of Popper's weakest and least convincing.

But I suppose I have always thought it must be obvious that generalisations are not certainties. Given the concerns that some other posters on this forum have about the thing they call "Scientism", if those concerns are justified, maybe it isn't that obvious after all.

Teh wrote: (Nested quote removed.)


Yes, you would have to explain why objects fall more slowly at the equator than at the poles. I still think it strange that we will almost accept a spinning earth as irrefutable, but an orbiting earth as merely a point of view.

You could also say that the whole other cosmos is spinning around Earth. It would be the same as far as the description of the system is concerned.

Skakos wrote: (Nested quote removed.)


You could also say that the whole other cosmos is spinning around Earth. It would be the same as far as the description of the system is concerned.

And that is irrelevant. Science is about explanation, and it is not the same as far as explanation is concerned.

Teh wrote: (Nested quote removed.)


And that is irrelevant. Science is about explanation, and it is not the same as far as explanation is concerned.

Science is about describing. Not about explaining.

And why wouldn't you think that the Universe is spinning around the Earth?



Think of a rotating bucket.

Then Enter Mach. This is the second half of the 19th century, and Ernst Mach does not believe in Newton’s absolute space, but is a relativist (soon to influence Einstein and his relativity, according to some), following in the steps of another great relativist, Gottfried Wilhelm von Leibnitz, who was Newton’s contemporary. Mach thought, what if the bucket were placed away of all things with mass in the universe? What if the bucket were the only thing in the universe? Would it still rotate? But with respect to what?

Skakos wrote:
Science is about describing. Not about explaining.

You are quite wrong. Give it a moment's thought and you will realise that science actually has a tendency to explain the seen in terms of the unseen. Evolution explains how diversity may arise, it does not describe it, or any particular incidence of it. The explanation of how massless fundamental particles acquire mass, has been known for 40 years. The explanation was the existence of a field whose ground state was not zero. A consequence of that explanation was that there should be a particle associated with that field.

In fact most scientific theories are discarded because they are bad explanations. Take for example the discovery of the neutrino. Rival ideas were discarded because they were bad explanations (though they describe beta decay just as well).

And why wouldn't you think that the Universe is spinning around the Earth?



Think of a rotating bucket.

Then Enter Mach. This is the second half of the 19th century, and Ernst Mach does not believe in Newton’s absolute space, but is a relativist (soon to influence Einstein and his relativity, according to some), following in the steps of another great relativist, Gottfried Wilhelm von Leibnitz, who was Newton’s contemporary. Mach thought, what if the bucket were placed away of all things with mass in the universe? What if the bucket were the only thing in the universe? Would it still rotate? But with respect to what?

Allow me to quote some Mach:

“The theory of relativity is just as unacceptable to me as, say, the existence of the atom or other such dogmas.”

Teh wrote: Allow me to quote some Mach:

“The theory of relativity is just as unacceptable to me as, say, the existence of the atom or other such dogmas.”

So?

Skakos wrote: (Nested quote removed.)


So?

Mach was a fool. You support him. Or, should that be you use him for support.

Teh wrote:You are quite wrong. Give it a moment's thought and you will realise that science actually has a tendency to explain the seen in terms of the unseen. Evolution explains how diversity may arise, it does not describe it, or any particular incidence of it. The explanation of how massless fundamental particles acquire mass, has been known for 40 years. The explanation was the existence of a field whose ground state was not zero. A consequence of that explanation was that there should be a particle associated with that field.

In fact most scientific theories are discarded because they are bad explanations. Take for example the discovery of the neutrino. Rival ideas were discarded because they were bad explanations (though they describe beta decay just as well).

I don't know, are explanation and description really discrete categories? I mean sure, they have a different purpose, but it seems to me at their core, they are the same. If you describe something in full, you have also explained it. If you explain something, that explanation is also a description.

To put it in the context of scientific theories: Steve has already said that the simpler theory is usually regarded as "better". That is because the function of theories is usually to predict future, unknown events. The most complicated theory possible is a mere description. It is exactly as complex as the real world, and hence, can never predict anything, because any future event requires a change of the description. A simpler Theory is an explanation, because it can describe not only the current state, but also a finite number of future states.

So saying a mere description is not a theory, or in other words, a model, does not seem accurate. It is just a model with very limited uses.