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Things that's accepted but has not been prooved yet

  1. Nov 18, 2005 #1
    Hi!
    I'm woundering what parts/things in physics that's being accepted but hasn't really been prooved yet.
    Is antineutrinos one of these things?

    Also if I remember this correctly neutrinos were accepted before they were prooved?
     
    Last edited: Nov 18, 2005
  2. jcsd
  3. Nov 18, 2005 #2

    jtbell

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    It's well established that antineutrinos exist and are distinct from neutrinos. At particle accelerators, we can produce beams of either neutrinos or antineutrinos, from the decays of other particles. When neutrinos interact with other matter in a detector, they characteristically produce electrons, or negative muons, or negative taus, depending on which "flavor" the neutrino is. Antineutrinos produce positrons, positive muons, or positive taus.
     
  4. Nov 20, 2005 #3

    ZapperZ

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    There is no such thing.

    Antineutrinos are so well-established experimentally, it is not even funny. An electron antineutrino is obtained from each beta decay.

    You were around back then? What evidence do you have that they were "accepted" before experimental evidence were produced?

    Zz.
     
  5. Nov 20, 2005 #4
    I think "accepted" is a very vague word. Yes, dirac (or pauli, i don't know) had neutrinos in from their calculations, but it was met with a healthy dose of skepticism from the community. It was not until experimental evidence came when it became "accepted".
     
  6. Nov 20, 2005 #5

    Pengwuino

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    What do you mean by "prove"?

    The Big Bang is one thing that popped into my head. If you use the idea of "experimentally proven" to mean proven... then I suppose you really can't directly "prove" the big bang. If you use mathematics however, you can say its proven.
     
  7. Nov 20, 2005 #6

    DaveC426913

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    BB hasn't been proven and never will be (without a time machine).

    The atomic theory of matter could be said to be proven. Since, well, we've seen them.
     
  8. Nov 20, 2005 #7

    Pengwuino

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    Then where do our models come from?
     
  9. Nov 20, 2005 #8

    Haelfix

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    Science is never 'proven', like a mathematical theorem. It is merely 'refined' and/or 'accepted'.

    Newtons law of gravity is 'accepted' b/c it has passed every experimental test in its realm of applicability ever thrown at it. Tommorow otoh if suddenly apples fall upwards, we would merely change the sign in front of 1/R^2 as compelled by experiment (or rather aliens would, bc we wouldnt be here any longer). There is nothing to say conclusively that such a situation couldn't happen, its just that we wouldn't bet on it =)

    Anyway, there are plenty of open conjectures that are still out there, many of which are thought to be correct (by almost everyone), but still tentatively unsure (usually b/c we can't make a proper falsifiable experiment or b/c theres an ambiguity in the theory).

    I don't know, a famous one is the 'no closed time like curves' in GR conjectured by Hawkings.
     
  10. Nov 20, 2005 #9
    Actually experiments aren't what "prove" anything. it is actually LOGIC. No one could ever ever ever prove me wrong if say "we exist." this is so because this statement makes perfect logical sense. No experiments have to be done, only simply logical reasoning. If someone said "in my opinion I don't believe we exist" they would be completely wrong. Just by the sheer fact that we are not nothing means that we exist; just by the sheer fact that i can think, interpret, and interact with the environment "proves" 100% that we exist. Logic is all u need to prove anything. When something makes perfect logical sense it is TRUTH, absolute truth, and can never be disproven such as my sinario above.
     
  11. Nov 21, 2005 #10
    I think haelfix has hit the nail right on the head. Its never possible to prove anything absolutely in science.

    And i don't think it has anything to do with the logic stuff. I exist, this exist, whatever.
     
  12. Nov 21, 2005 #11

    ahrkron

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    Besides logic, you need to establish the premises in which to start reasoning. In many cases, experimental evidence is the only way you can determine what premises to start with.
     
  13. Nov 21, 2005 #12
    Logic determines those premises in which to start reasoning. How I define logic is interpreting the environment in which one exist and arriving at a specific conclusion about something within that environment that is completely consistent with the laws of that environment. Thats what logic is. For example: if I notice a tree and a leaf falls off from it, it would be illogical for me to say all trees have leaves that fall from them unless I actually studied it in comparison with all the laws of the environment in which it exist. Once done then i can safely say which types of trees exist and which ones will have leaves that fall.
     
  14. Nov 22, 2005 #13

    DaveC426913

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    Well, you have just thrown out the last two millenia of science. The Greeks believed that the universe could be understood from their couches through logic alone. Unfortunately, it led them quite astray. It wasn't until the scientific method was established, more than a millenium later that science and civilization truly advanced. That was when we threw away what we thought we knew, and looked around to see what was actually happening.

    Toss out the scientific method (hypothesize, experiment, observe, theorize) and you're back in the Dark Ages.
     
  15. Nov 22, 2005 #14
    i never said toss out scientific method. the scientific method is just a way of looking at things logically. when we were in the dark ages we didn't actually look at things logically because anything someone observed was not taken fully underconsideration. No one looked at every single aspect of situation 100% of the time. The scientific method is just a way of taking all aspects of a situation even more into account. So actually the scientific method is just a way of looking at things even more logically. It doesn't disprove logic rather it confirms it.
     
  16. Nov 22, 2005 #15

    Kea

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    Oh dear, no! The scientific method was born from the recovery of the ancient works. Science needs both method and madness.
     
  17. Nov 23, 2005 #16

    DaveC426913

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    No, it's not. The point of the Scientific Method is to NOT rely on logic. The point is to rely on experimentation and observation. Even when (and particularly when) it conflicts with logic.

    The rationale is "Logic can be flawed. Empirical evidence is the only trustworthy source of knowledge."

    (This is not to say that logic is not employed in the SM to develop a theory; it is to say, quite emphatically, that, even with superhuman logical thinking, we cannot learn about the universe from our living room chairs.)
     
  18. Nov 23, 2005 #17

    DaveC426913

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    Because we've seen them directly, we know they exist. Whatever else they are, we know a sheet of copper is made of little chunks of copper "atoms" about yay big. No amount of future theoerizing or observation will change what we have seen up to this point.

    What we don't know (i.e. have not proven), is how they work. Our models (which model protons, electrons, quarks, etc.) attempt to explain how they work.

    We're seen evidence of quarks, but our evidence is somewhat more indirect. Our models are pretty (OK, very) accurate, but future models and evidence may yet change our model of subatomic particles.
     
  19. Dec 9, 2005 #18
    ok, the problem here is semantics. we have different definitions for logic. The thing here is that u are defining logic differently than me. I define logic as truth, therefore according to this definitino it can't be wrong. Logic is always 100% true. i don't define it as something that's man made. I define logic as the reality, the absolute reality. so considering this definition the scientific method does in fact try to prove what is logical (truth, reality) but the problem is that even with this advanced method as opposed to our dark age one, it still doesn't take everything into account. but it does try to and actually does it more than humanity used to.

    Do u see how i am actually being consistent that it was just a misunderstanding of definitions.
     
  20. Dec 10, 2005 #19

    DaveC426913

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    OK, no. The problem here is that you're using the word incorrectly.

    One doesn't invent definitions as one sees fit. Unless you want to have discussions with trees, you should stick to the established language.

    A really excellent way for you to help yourself is to read up on the subjects you're interested in so that you make sense in discussions with others.
     
  21. Dec 10, 2005 #20

    HallsofIvy

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    That is not the way anyone else understands the work "logic"!
    For one thing, "logic" is a process, not a fact. Logic is a process that shows that one statement is true IF another is true. All logical arguments have to come from an initial statement that is accepted as true. Logic asserts that a given argument is "valid". It does not assert that the conclusion of the argument IS true.

    IF you know that a given statement is true, and that an argument leading from that statement to a conclusion is "logically valid", then you know that the conclusion is true. But logic can't tell you whether or not your initial statement is true.

    In mathematics, all statements are of the form "if.... then" so that the initial statement doesn't have to be verified. In science, the truth of the initial statement is based on observation and experiment. Of course, those are never perfect- that's why science is entirely an endeavor to show that some theories are FALSE, thus giving at least more confidence that the ones remaining are true. You can never prove that a scientific theory is true, just that others are false.

    No one could ever prove you wrong because the statement is meaningless.
    I would accept "exist" as a term in logic but I have no idea who you are referring to by "we". If you were to say "I exist", I would probably be compelled to accept that there is something (perhaps a computer AI program or my own delusions) sending that message to me. But "we" implies more than one of you and I have no reason to accept that!
    If you mean "you and I"- the one sending the message and the one receiving it- I would still have to consider the possibility that they are, in fact, one and the same- perhaps I am "hearing" voices created by my own mind- in which case the use of "we" is incorrect and "we exist" is false.
     
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