Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Does anything really exist?

  1. Jul 25, 2011 #1
    I think this is the basis for some famous philosophy, but I'm not sure.

    I thought of this on one of my sleepless nights, which are pretty often.

    Anyway... Does anything really exist? Or is it all just electric impulses from our nerves that our brain deciphers into sound, taste, hearing, sight, and smell? Can everything be described as these impulses? And while I am here, is it possible to make a machine that can stimulate areas in our brain that receive the senses, and therefore create a virtual world that is indistinguishable from reality?

    I hate to quote the Matrix, but it pretty much sums up everything I've been trying to say.
    "If this is "real", then "real" is merely electrical signals interpreted by your brain."

    I don't want to start a flame war, I am just curious as to what others think.
  2. jcsd
  3. Jul 25, 2011 #2
    you must have heard of hallucinations...try this video from TED [http://www.ted.com/talks/lang/eng/oliver_sacks_what_hallucination_reveals_about_our_minds.html] whatever the brain "sees" is reality. thats what many meditators experience [ travelling to elsewhere land, visiting dead, or seeing god ] thats very much real for him but need not be for others.

    in my view, you its real what your brain projects but people through out the history have claims to train there minds to distinguish between hallucinations and reality and stop getting hallucination once and for all. they call it "enlightenment --looking into things the way they are"
    i don know how much thats true.
  4. Jul 25, 2011 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    Every sensation you have is the result of sensory input to the brain, there are clear examples of then this sensory input isn't "real" e.g. dreams, hallucinations and http://en.wikipedia.org/wiki/Blind_spot_(vision)#Blind_spot_test".

    Whether or not thing's are "real" depend on your definition of http://en.wikipedia.org/wiki/Reality" [Broken] advocate the argument that one can never be sure if what one see's is "real" therefore the only thing one can be sure of is the existence of one's own mind.
    Last edited by a moderator: May 5, 2017
  5. Jul 25, 2011 #4
    Generally, what most people see is real, if something is seen/felt only by you its not real.
  6. Jul 25, 2011 #5
    True, but after all, it's only money.
  7. Jul 25, 2011 #6
    I don't mean to argue, but isn't sensory input largely inhibited during dreams? In my understanding, the perceptions during dreams are generated within the brain and are hardly influenced by external stimuli.
  8. Jul 25, 2011 #7


    User Avatar
    Staff Emeritus
    Science Advisor

    True, I meant to imply sensory input and perception.
  9. Jul 25, 2011 #8
    The only directly experienced reality is that which occurs in the conscious mind. However, through various methods (especially the scientific method) we can construct a model of objective reality, that is, a model that makes predictions which other conscious minds can verify.
  10. Jul 25, 2011 #9
    The choice whether anything exists is real.
  11. Jul 25, 2011 #10
    I think its a meaningless question. Not just silly mind you, but truly meaningless gibberish along the lines of Louis Carroll's "The Jabberwocky" that merely sounds compelling. I hear these kinds of nonsense questions all the time from people who insist everything is made of "energy" even though energy is defined by mass. Once when asked such a nonsensical question Stephen Hawking responded, "North of north." In this case I'll respond, "Nonexistence exists!"

    For only $39.95 I'll send you endless drivel just like this that explains life, the universe, and everything.
  12. Jul 25, 2011 #11


    User Avatar

    Staff: Mentor

    wuli, you're my new hero.

    Also, $39.95 is pretty cheap!
  13. Jul 25, 2011 #12


    User Avatar
    Gold Member

    Everything past the ### above is simply rhetoric; it embellishes how strongly you feel, but does not actually make a case for your opinion.

    You have not said how you think it's meaningless gibberish. How is 'is anything real' not a valid question, worth some consideration by those inclined?

    I'd like to hear you support that.
    Last edited: Jul 25, 2011
  14. Jul 25, 2011 #13
    Okay, even though that kinda sounds like flaming, I'll accept it as an idea. Philosophy is a whole bunch of these "nonsense, meaningless, 'north of north' gibberish questions." Get used to it. There's a reason why philosophy and science don't mix.

    I already know what explains life, the Universe, and everything. The Answer? 42!

    Now all you need is the question...

    I'LL sell it to you for $9.95!
  15. Jul 25, 2011 #14


    User Avatar

    Staff: Mentor

    Seriously? We define what is "real" and our definition


    Anything else is not real e.g. imaginary.

    Not hard actually. Real is what we define it to be.
  16. Jul 25, 2011 #15
    Define your terms. What is "anything," and what does it mean to "exist?" It seems clear to me that something exists, otherwise I wouldn't be thinking anything, seeing anything, or typing anything right now.

    Electric impulses, nerves, and brains are all assumed to exist because they have been observed in reality. Stating that what we perceive doesn't exist negates the whole idea that electrical impulses in our brains exist.

    Theoretically. We can already induce flashes of light in the brain with magnetic fields. No reason to think that you couldn't send impulses into the brain to create a virtual world.
  17. Jul 25, 2011 #16

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The real question from The Matrix is the same one asked by Rene Descartes. It is not whether anything is real, rather, how do I know my thoughts [perceptions of apparent external stimuli] are my own and not imposed on my mind by an evil genius? Also, Descartes figured that one out in six meditations.
    Last edited: Jul 26, 2011
  18. Jul 25, 2011 #17
    Cool. I knew that I had gotten it from somewhere.

    @CJames-These are my definitions.

    Anything-Any physical object that can be measured (i.e. weight, mass, height, width, ect.)

    Exist-Any physical object that can be observed with the five human senses or aids (i.e. x-ray, ultrasonic imaging, ect.)
  19. Jul 26, 2011 #18
    It appears that you've answered your question.
  20. Jul 26, 2011 #19
    It appears that I have. No more philosophy for me tonight, I'm too sleep-deprived and answering my own questions and overall being rather clueless. I'll try to rest, then come back.
  21. Jul 26, 2011 #20
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook