Physics eventually gets down to assumption and acceptance

[Aquagem]

Well put, Lee.

 

Sanctus, I guess I didn't really take you up on the real issue here, either. You actually ask two things:

 

1) Is everything we know based on assumptions and acceptance of these assumtions?

 

2) Can we ever know anything about why things happen?

 

To me these are related but we should try to define an angle of attack because they can also be discussed separately.

 

Sanctus, it seems to me that you are defining "assumption" as anything we accept as (conditionally) true. I would add a few more distinctions. "Assumptions" are more or less arbitrary notions about what, how, or why something occurs. They are like "ad hoc" explanations - "well, it might've happened because..." - for which creationism is famous. "Estimates" are similar, except that they are based on prior experience, and thus are not assumptions, pe se. Our experience may be incomplete or flawed, leading to incorrect conclusions and faulty estimation, but they are not arbitrary. "Theory" in the scientific sense may trace to one or more root assumptions, e.g., "The laws of nature are everywhere the same," allowing us to infer something about the distance to the Adromeda Galaxy by the similarity of variable stars. But scientific theory is radically distinguished from "wild" or "mere" theories prevalent on the street and in the church because of a vital hedge between them and their assumptions, ad hoc hypotheses, and tradition alone -- and that vital hedge is that scientific theories are compared against what we assume is an external reality. If they don't pass that test, it's mutation time, or extinction time, for the theory. So, between "assumption" and "acceptance", there are other steps that must be taken, "testing and evaluation" being chief among them.

 

This process of testing and evaluating assumptions creates a tough cord of phylogenetic descent for theories. That doesn't mean they are "right", "complete", or in any way "ultimate". It just means they lead from tentative to more stable knowledge, which then allows us to predict a wide variety of phenomena accurately, like getting a space probe to Mars.

 

To say that all of physics is only observation is therefore incorrect -- or incomplete. Science is importantly bound to test its hypotheses against observations, but it's really the THEORY that is being tested. Postmodernists would have you believe that all theories are equally valid (which means, invalid) and that stable knowledge is an impossibility. But science, alone among arbitrary belief systems, is channeled and guided by its requirement for verification against the natural world.

 

Much to say about that later, since, of course, our ability to know the "natural world" is never perfect, either.

[sanctus]

Welcome to the forum Aquagem.

 

Very nice post, I agree Ididn't write well some things.

 

About your first paragraphe:

Ok, there is a difference between estimates and assumptions; by saying assumptions I actually meant an explanation to a phenomena based on something which is logic from a scientific point of view (what should let creationists away), but there is no fundamental reason to it. For example,in particle phisics one assumes that an electron is point-like, this assumption is made on logical thinking (nothing has shown us the contrary yet), but why is it point-like? There is no fundamental answer to that, therefore we still assume or if you want estimate it to be such.

When I talked about acceptance I implicitly thought that there is experimenting in between, so I completely agree with you on that.

 

Second paragrpahe:

Yes, it seems to me that Einstein said while introducing his special theory of relativity, that he presents just an preciser approximation of reality than Newton.

 

Third paragraphe:

 

How can we test a theory? I mean we can never know that it's right everywhere, we can just see to where it applies.

[Doctordick]

Hi sanctus! I was just poking around trying to see what kinds of thoughts had been propagating around this forum when I happened to run into your post.

 

It seems to me that all physics is only descriptive and in addition there is no explication which doesn't start from assumptions.

This is an absolutely valid observation. It is a direct consequence of the way science is done and is very much a detail of the boundary on what is usually called “compartmentalized thinking”. Assumptions are made as to what is and what is not known (thus establishing the boundary of the “compartment” within which one is to think): i.e., the facts which bound what one is attempting to explain.

 

Take for example all the electrodynamics, it starts from the assumption that there is an electric charge and then makes up the model which describes the phenomenas.

Exactly correct. What people like Rade cannot comprehend is that the things he refers to as “facts” are assumptions that his world view is valid. Qfwfq is much in the same circumstance though for a very different reason. He is educated in physics and, as such, he has been trained to think in “compartmentalized” ways. He does not comprehend that his fundamental view is a religious conviction (created by his training) that these boundaries of his thinking are reasonable and sufficient. Exactly the same presumption made by the religionists of the dark ages. My comments concerning his “bringing of excess baggage" to the arguments have invariantly fallen upon deaf ears. He has utterly no idea that he is making assumptions in all of his complaints.

 

I think it has to be so, because there is no way to know that a theory is the ultimate one, but I think it's anyway very surprising: we never know real reason for any phenomena.

That is indeed a very real issue to be kept in mind at every step; however, the more one is convinced that their world view is valid, the more difficult it is to maintain such an objective perspective. Particularly if one's income depends upon the validity of their beliefs. :lol: :lol: :lol: :lol:

 

 

Have fun -- Dick

[Rade]

... What people like Rade cannot comprehend is that the things he refers to as “facts” are assumptions that his world view is valid. Dick...

 

Hi DD, so, it is your assumption derived from your world view that:

 

facts ---> are assumptions of a correct world view.

 

I have a few questions.

 

1. How exactly did you reach the conclusion that I do not comprehend this ?

 

2. For you to claim that a fact is an assumption indicates to me you have no idea at all what I comprehend and what I do not comprehend.

 

So, just so you finally understand what I do and do not comprehend about the word "fact", here is how I define the word:

 

fact = confirmed observation.

[Ken]

This is called the Incompleteness theorem and was proved by Goedel a long time ago. :P

 

 

An unfortunate choice of a word. B)

 

"Proof" has too many different meanings. It leads to more confusion here.

 

To say that Goedal "proved" something you really need to specify the variant of "proof" that you are using. It's true that he offered a Mathematical, or Logical, proof but the term has no meaning in the probabilistic universe of Science. The very base of the Theory of Incompleteness argues that "proof" within Science is impossible.

 

Broadly speaking Science is one of several Methods of Inquiry. Science uses the Scientific Method to generate explanatory statements about observed physical events, and then testing those explanations through prediction-testing observations, i.e., experiments. Thus "certainty" or proof is always dependent on the completeness of observations - an impossible criterion to meet since there ae always an infinte number of possible observations.

 

In terms of the thread title Physics, like any other Science, rests on assumptions (Theories) and acceptance is based on how close to probable certainty the assumptions manage to achieve through repeated prediction-testing.

 

 

:)

[Ken]

Yes, no, well, this is only partially true. We can say that science is based on empirical data, i.e. since something happened one way yesterday, we will expect it to happen the same way tomorrow.

 

 

However, we cannot prove that it will. We can only prove the likelyhood that it will happen the same way (ie, the probability). You can never have a 100% probability for anything in the physical world.

 

 

So a prediction is only that, a forecast based on a certain probability.

 

 

It's like the coin toss thing - toss a coin and there's a 50% chance that it will turn up heads. But flip it 10 times and I'll bet you it doesn't show heads 5 times. However, the more your throw it, the closer to 50% you will get. That is why science needs to test, retest, retest, etc ad naseum...because we need to verify that our predictions are based on the correct probability.

 

 

This forum needs a "thumbs-up" emoticon. B)

[Ken]

Tormod. Maybe you guys are stull confusing chaos theory with randomness. Probability is based on randomness, which means we don't have control over, or know all the variables. If we did, there would be no need for probability and statistics. In every observable case, however, cause and effect is the rule. That means, with perfect knowledge, every event is predictable. In a closed system, such as, for example, computer programs, the outcome will always be the same given the identical input. Randomness may not even exist within quantum reality. Determinism wil stand until someone can prove an uncaused event has ever occured. (My challenge, several times in these forums.) Linda

 

 

Determinism is a useful model.

 

However your statement: "Determinism will stand until someone can prove an uncaused event has ever occured" appears to me to suffer from several problems. First I suggest that you substitute the word "demonstrates" for "prove". To "prove the occurrence of "an uncaused event" would require an infinite historical observation.

 

Second in macro-physics cause and effect hold up to testing quite well - the probability of it being "true" is pretty close to that elusive P=1.0. On the micro level it doesn't seem to hold up nearly as well. Quantum emission at very low energy levels gives every appearance of being random. Raise the energy level and the increased number of random emissions starts to look pretty non-random. (At least that's the way it was explained in the 1960s when I was in graduate school).

 

That, and recent reports on the activity of sub-sub-atomic particles B) suggests that your challenge has been met and bested.

 

By the way, where can I buy one of those non-random computers? I've never had one that wasn't possessed by a poltergeist or two....

[Ken]

I agree, knowledge of all variables would allow one to predict with 100% accuracy, but there is no proof of that other than logic. There may not be any counter examples, but you have to assume that it is correct in order to prove it.

 

 

It's more complicated than that. Assuming you've accounted for all variables you still have the problem of assessing their interactions. Not only that, but even with a single variable you need to predictively-test every possible value of that variable. So, if you have confirming evidence from values of 1.3 and 1.4, what about 1.372591? And what about values outside the range of 1.3 and 1.4?

 

Our ability to observe is always finite within a world of infinite values, thus you never reach 100% accuracy, or P=1.0.

[Tormod]

Hey Ken! Welcome to our forums. The topic you are in dates back to 2004! But thanks for pulling it back up.

 

To say that Goedal "proved" something you really need to specify the variant of "proof" that you are using. It's true that he offered a Mathematical, or Logical, proof but the term has no meaning in the probabilistic universe of Science. The very base of the Theory of Incompleteness argues that "proof" within Science is impossible. :P

 

Okay, let's use the variant which Wikipedia offers, for the sake of discussion:

http://en.wikipedia.org/wiki/Gödel's_incompleteness_theorems

 

This forum needs a "thumbs-up" emoticon. :)

 

B) (We just recently switched forum software, so the emoticons are a bit hard to find...working on it).

 

You can also use the little "+" icon in the lower right of a post you like to "promote" it.

[Ken]

Hey Ken! Welcome to our forums. The topic you are in dates back to 2004! But thanks for pulling it back up.

 

I guess I'm a slow reader....

 

 

 

Okay, let's use the variant which Wikipedia offers, for the sake of discussion:

http://en.wikipedia.org/wiki/Gödel's_incompleteness_theorems

 

 

 

:) (We just recently switched forum software, so the emoticons are a bit hard to find...working on it).

 

You can also use the little "+" icon in the lower right of a post you like to "promote" it.

 

 

Dinner is calling. I'll check out the wikii and get back to you.

[Qfwfq]

Actually it wasn't Ken that bumped the thread back up! Also, Ken, currently there is a multi-quote feature so it isn't really necessary to make several posts in a row.

 

An unfortunate choice of a word.

If I had been here back then, I rather would have said that the point he replied to wasn't a case of Gödel's theorem at all.

 

To say that Goedal "proved" something you really need to specify the variant of "proof" that you are using. It's true that he offered a Mathematical, or Logical, proof but the term has no meaning in the probabilistic universe of Science. The very base of the Theory of Incompleteness argues that "proof" within Science is impossible.

You would have it that Gödel proved that it is impossible to prove anything?

 

Gödel's theorem is about formal systems which comprise number theory, it means that in any of these there will be undecidable propositions. It is a mathematical theorem and the proof of it has nothing to do with empirical observation. Yes, "proof" has many different meanings but it is only a matter of understanding the one that is appropriate for each case. For instance, Fermat's theorem has been proven despite the fact that no finite amount of rude testing would suffice.

[Ken]

Actually it wasn't Ken that bumped the thread back up! Also, Ken, currently there is a multi-quote feature so it isn't really necessary to make several posts in a row.

 

If multiple posts are irritating I'll be happy to use the multi-quote feature.

 

If I had been here back then, I rather would have said that the point he replied to wasn't a case of Gödel's theorem at all.

 

You would have it that Gödel proved that it is impossible to prove anything?

 

Gödel's theorem is about formal systems which comprise number theory, it means that in any of these there will be undecidable propositions. It is a mathematical theorem and the proof of it has nothing to do with empirical observation. Yes, "proof" has many different meanings but it is only a matter of understanding the one that is appropriate for each case. For instance, Fermat's theorem has been proven despite the fact that no finite amount of rude testing would suffice.

 

 

I acknowledged that it was a mathematical argument. The gist of my comment was that it had no relevance in the realm of Science and, if it were offered as an argument for the issue at hand the only conclusion would be that "Proof" is not a valid concept for Science.

 

I do recognize that Mathematics is not a Science but rather a form of Philosophy. :shrug:

[Qfwfq]

I acknowledged that it was a mathematical argument. The gist of my comment was that it had no relevance in the realm of Science and, if it were offered as an argument for the issue at hand the only conclusion would be that "Proof" is not a valid concept for Science.

Many mathematical proofs are useful in sciance, it's just that Gödel's theorem is not about the matters of empirical observation and induction.

 

I do recognize that Mathematics is not a Science but rather a form of Philosophy.

Yes, it is purely an exercise in logic.

 

However, what we call science today was once called natural philosophy and science meant any body of knowledge, these changes were fairly recent on the historic scale of time. Mathematics remains a great language and tool of the sciences; that's why they currently teach it in science faculties. :lol: