dont know

wolram

we dont know what gravity is yet we can calculate its effects
we dont know what a photon is yet we say c is limit
we dont know how big our universe is yet we predict that it will continue to expand
we dont know what dark matter is yet we predict it exists
we dont know what a singularity is yet we say that is what the universe started from
etc,etc, so we are makeing calculations on observations, as the human race has only been makeing these observations for a few hundred years,
a mere heart beat compared to the age of the universe, how do we know
that any of the above are constant, true, or exist, is there one thing that is known will not change with time, "eons", that we can base our science on.

einsteinian77

YES, mathematics [:))]

wolram

if you canot count what is there how can math prove anything?

Mentat

No, we don't know exactly what gravity is, but General Relativity is a very well-supported theory on it, and has made been making accurate predictions. If our current concept of gravity is flawed, then the predictions should be (in some instances) flawed.

Well, actually we've set c as the limit of all objects.

Why does one have to know how big something is, in order to tell that it is expanding (or that it will continue to do so)?

Because of having seen phenomena that can be explained through the postulation of it's existence.

We know what a singularity is, we just don't know how it behaves, or whether it can physically exist.

Why do you seek such certainty? If it works for now, it's useful.

jeff

Science is an invention and defined in terms of method and convention, not in terms of the natural phenomena that scientists study.

drag

No.

Mentat

Are you certain?

wolram

you are all being defencive, i agree that the most up to date science
explains our observations to date, what i am asking is, is there one thing that is constant and timeless that can provide a proof or base line for our theories, or are all our theories just a human concept.

Mentat

But I asked you, "why do you seek such a thing".

Besides, if there was something that was absolute, it would be impossible to prove that it was absolute by scientific methods.

marcus

Mentat asks: "why do you seek such a thing?"

The question is about a metaphysical basis for physical models and laws.

First observe that it does not belittle a physical law, if it has a good track record of prediction, to say that it is "just a human concept."

It is pretty remarkable that mere human concepts---which everyone should realize are approximate in nature----as for instance F=ma is approximate rather than exact----should be so incredibly successful.

How does a species evolved from fish happen to be able to come up with such elegant and powerfully predictive laws in the first place?

About the metaphysical question----some eternal touchstone for physical law, some ultimate criterion. No reason not to wonder about this. Great scientists have speculated for example about the elegance and beauty of physical laws.....what does it say about us or the universe that the successful laws so often turn out to be beautiful? It is not a scientific question, or even well-formulated but it is a question that an intelligent person can ask.




__________________
"He who joyfully marches in rank and file has already earned my contempt. He has been given a large brain by mistake, since for him the spinal cord would suffice."

-Mentat's neat Albert Einstein quote has a bearing on metaphysical questions like this

drag

No, not entirely. [;)]
(For example, mathematics seems like a very
"strong" and primary part of science today
and one that we would seemingly not be able
to do without.)

Tom Mattson

No, science does not prove anything. Science is about "conjectures and refutations", as Popper put it. We hazard a guess about the way nature works, and then try to prove it wrong. When we succeed in that, we come up with a better guess and do the same thing. It sounds as if you are trying to find a way to prove our concept of the universe right, which is a hopeless task.

Yes, and that's exactly what steinitz has already told you.

wolram

sorry if have not formulated my question so well that you do not fully understand, the deeper one researches a subject in science
one finds it throws up more questions, if i said i know all there is to know about say a hydrogen atom, even if i had made it my lifes work
i would be wrong, what i am asking is, is there anything in science that canot be wrong, somthing that is invariant in value and time,
the closest i can find is speed of light in a vacuum ,but i canot say this is a constant that has never changed, we exsist if that is by chance or design it does not alter the fact, but there are many
variables that had to be correct for our existance to be possible, but our exsistance is a FACT, there must be others, unless we are living in a chaotic universe.

Tom Mattson

Wolram,

You weren't unclear at all. You just aren't seeing how our responses answer your question.

If you are asking about scientific theories, the answer is "No. No such invariant exists." Again, science is not in the business of proving theories correct, it is in the business of proving theories wrong. This is related to my next point, which is...

If you are asking about the object of scientific study (aka "the universe"), then the answer is "No one knows." This is a matter of epistemology, as reality is not something that one can know a priori. This is precisely the reason that science is conducted in the way that it is.

wolram

hi tom, i do understand the methodology of science, but i have given
example of fact that is irifutable, our existance ,is that all we can
say?

Tom Mattson

Ah, so you are looking for manifestly indubitable propositions. We have hashed this out in several threads in the Philosophy forum over the course of PF's existence.

One might offer that "the universe exists" is just such a bedrock truth. But then, our idealist friends are quick to point out that the only way you know about the universe is by sensory perception of it. Thus, all you really know is that "I am receiving data and processing it", or in other words, "I am thinking". This was Descartes famous argument, "I think, therefore I am". But he didn't really prove that "he" exists; he leapt to that conclusion from the fact that he is thinking. Stripping off the "I" from Descartes' argument, we have what I think is the closest thing to an absolute truth as I can come up with: "thought exists".

All else can be doubted.

Mentat

The explanation of Descartes' philosophy left a few things out, but I want to commend Tom on not having totally misconstrued it (no offense to those other members who screwed it up so badly... [:)]).

Anyway, Tom's right - and Wuliheron has been saying it for as long as I can remember: Existence is the only thing we can be certain of.