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What does physics describe?

  1. May 19, 2003 #1
    My mom and I were debating what physics described. Here is my mom's argument:
    "Everything is a result of physics".

    My argument: "Mom, the semantics you're using is incorrect. Physics only describes the universe; it doesn't cause it. The correct semantics is as follows: the universe is the result of what physics describes."

    Okay, she seems to surrender....but still holds on to hope. We agreed that I post it here, to get your comments.

    Another thing: My mom says "We know only 1/8 of physics".

    Me: "This paradoxical, mom!! In order to make an estimate, in this case a fractional estimate, we need to know the denominator. The denimonator is everything we know and everything we don't know. Therefore, since we can't know what we don't know, the statistics you present have no meaning."

    Is my logic right?

    Thank you!! :wink:
     
  2. jcsd
  3. May 19, 2003 #2
    i dun think everything is result of physics
    beside physics , we still have the other knowledge
    even the physics also should consider the probability in sometime
    my idea is physics describes why the result come out like that from universe:wink:
     
  4. May 19, 2003 #3
    The physics we have today, is only a model of nature, while nature is still mysterious. Take a falling ball, for example. Newtonian physics will describe the motion in a vacuum to nearly 10 decimal places. Add a small correction, air resistance, and Mechanics still works, but it is a more complicated differential equation. Adding relativistic corrections takes more work, but gives you the highest relavent accuracy (QM corrections for macroscopic objects are truly negligable).
    Philosophically, physics is the language of nature, but in reality we just have a very good 'map.'
     
  5. May 20, 2003 #4
    Majin - If I were you I'd be proud your mom has the general logistical capability to say such a statement as:

    "Everything is a result of physics."

    Argueing the truth of that could sure be done, but dammit if your mom ain't making a statement that most people couldn't even understand.

    The majority of this idiotic planet would say:

    "Everything is a result of God."

    I'd be proud. Is she single? Gimme her number!
     
  6. May 20, 2003 #5

    ahrkron

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    If I had to choose only between those two statements, I'd definitely go for yours, Majin.

    I would state it in yet another way: What we call physics seems able to describe everything we can measure.

    or: The universe is a result of entities and interactions that we can measure and describe ("physics" is just the name of such description and the method by which we obtain it).

    Absolutely.

    Finally, allow me to say, you both should be really proud of each other. I don't think it is common for mother and daughter to have such kind of discussions.
     
  7. May 20, 2003 #6
    Although to the causual listener your conversation might sound intelligible, it sounds like something out of Alice in Wonderland to me. Saying everything is the result of physics can be interpreted as tongue in cheek humor. Its like saying "Everything is a result of Quantum Mechanics, which is random and has no cause." To then add that we only know 1/8th of physics is like saying, "We only know 1/8th of the unknowable, 1/8th of that which has no cause and is random."
     
  8. May 20, 2003 #7
    Majin, she is partially correct (read the link below). Tell her that actually everything (including physics, of course) is the result of math (which is just logic).

    This is so simply because both logic and universe have the same original presumptions.
     
    Last edited by a moderator: May 20, 2003
  9. May 20, 2003 #8
    Hey, don't offend the whole planet. This is only true for uneducated nations. I've been in most of Europe and people there do not think this way, especialy in Eastern part of it.

    What country have you made this observation from?
     
  10. May 20, 2003 #9

    Eh

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    It's most of the west.
     
  11. May 20, 2003 #10
    Exactly, I would not call the US uneducated for example. The real issue seems to be how capitalistic a country is. The more capitalistic, the more religious. The more impoverished and capitalistic, the more fundamentalist and Catholic.
     
  12. May 20, 2003 #11

    drag

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    Greetings !
    This statement implies a certain definition
    of physics which equates it to all observation -
    data input we have as well as things that
    exist in some reasonable or unreasonable
    for us manner and that may not be indicated
    in any way by observation.

    So, that definition is incorrect I think.
    Physics is defined as the basic axioms we conclude
    solely from observation (at their lower level of
    complexity behavior) first. Second, if we have not
    yet included some of the observed in physics
    then the everything part is again problematic.
    I'm not entirely certain what you meant
    by that statement. It sounds like one and the
    same as your mom's, except you changed "physics"
    into "what physics discribes".

    Again, the approach is actually reversed.
    Physics is the result of the Universe.
    Further more, only of what we can observe
    of it. Physics is a human-made theory, not
    a word meant to imply some all-inclusive
    Universal stuff(though that's its eventual -
    probably unprovable purpose).

    I agree with you about the "1/8" stuff.
    btw, did you ask your mom why she said that ?
    Indeed, but I think you should add - "probably"
    (in this and any other case related to the Universe).

    As for that "just logic" part, I'm not entirely
    certain what you're talking about. There
    are potentially infinite definitions possible for
    that word, not to mention that it's original
    assumptions in the more familiar to us cases
    are also enitially based on observation.

    It is probably pointless, and constitutes
    absolute assumptions or at least unlikely - beliefs,
    to postulate things that are not related to
    observation - "closed loops" as I call them,
    that have not originated from observation and
    do not make conclusions solely regarding
    observations.

    LA makes good points...

    Live long and prosper.
     
  13. May 20, 2003 #12

    yes...i agree:wink:
     
  14. May 20, 2003 #13

    drag

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    Yep, definitly sounds like total BS to me...:wink:
     
  15. May 20, 2003 #14
    The problem is just semantics. It depends on what you define "physics" as. Is it "the study of", "rules formulated from the study of", or what you're actually studying? ...However you want to define it.
     
  16. May 20, 2003 #15
    Physics is the useful study of motion. Some ways are more accurate than others, but require unnecessary mathematical precision and complexity for what people usually want to use them for. What matters is how useful they are to us as individuals and organizations. Needless to say, because we are ignorant we can find the answers.
     
  17. May 21, 2003 #16

    drag

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    The definition of the science of physics is
    indeed unclear - how can you define things
    that you do not yet fully know, after all.
    However, it's NOT THAT unclear as you imply.

    Live long and prosper.
     
  18. May 21, 2003 #17
    I agree. You should probably ask her why physics is any more likely to be the "cause" of existence than other fields of study.

    Beautifully reasoned, if I may say so.
     
  19. May 21, 2003 #18
    Re: Re: What does physics describe?

    The Universe cannot be said to have "pre-assumptions". It's not a field of study. It's a collection of all things. Maths, on the other hand, is just one (of the many) ways that we have to describe the universe.

    If you'd like, I can re-post my original "Hurdles" thread - though I thought the point had been made.
     
  20. May 21, 2003 #19
    What physics describes is the universe. Physics is a study of, whereas in my mom's point of view, the universe was a result of physics. This doesn't make sense because the universe can't be a result of physics because physics describes the universe.
    My analogy I presented to her: 'Think of it this way: you're describing a mountain range, and you're writing your observations down. The mountain range is not a result of the observations you wrote down. But the observations are the result of the mountain range, so to speak. Note that's only partially true...'

    That was the point I was trying to make, drag.

    Could we say that mathematics is only an approximation of the universe as we see it?
     
  21. May 21, 2003 #20
    Re: Re: Re: What does physics describe?

    That is the presumption whivh makes logic and math to work - that something exists.

    Nope. Description never PREDICTS how things will work. Math does. Math is not a description - it is the way things work. (And the only way, because it is just the way of logic).
     
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