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Medical How does a physical brain create non-physical things?

  1. Mar 13, 2007 #1
    I know this is probably a huge question to ask, and would be surprised if anyone knew the answer. It is, in my opinion, a question that is key to the understanding of consciousness.

    My problem is this:

    I build a robot that behaves and looks exactly the same way as me. It is simply not possible to tell the difference without taking a look inside.

    One day, a scientist does a test on me and my robot clone. A high pitched noise is played, and also a low pitched one. We are asked to say which one is the high pitched noise and which one is the low pitched noise.

    The robot completes the task because sensors in its ears can distinguish between various frequencies in the waves of air molecules.

    I complete the task because I can hear which one is high pitched and which one is low pitched. My ears must work in the same way as the robot's sensors, however, somewhere between my ear's ability to detect movement and my conscious experience of it, something is created which does not physically exist: sound. The same applies to colour- it is my understanding that "colour" does not exist; all that exists is wavelengths of light which the brain mysteriously turns into colour.

    Sorry if that's a rather long-winded explanation of what is essentially a simple question.
  2. jcsd
  3. Mar 13, 2007 #2
    Your question implies that the brain creates non-physical things.
    I think that is not the case.

    Non physical things simply do not exist.
  4. Mar 13, 2007 #3
    So then would you describe sound and colour as physical things?

    It does sound like nonsense to say something is "non-physical", but that's the only way I can put it, because I think sound is completely different to movement. If somehow every single conscious thing in the universe was to suddenly be taken apart, atom by atom, then what would happen to colour and sound?

    My answer is that they cease to exist. But if they are physical, then surely they must "go" somewhere.

    Sorry, I know I've probably been putting words in your mouth- so how would you describe colour and sound?
  5. Mar 13, 2007 #4
    You're discussing 'qualia'. Google/Wikipedia it.
  6. Mar 13, 2007 #5
    Light, Sound, Action Potentials.

    Let's throw out "physical" and replace that with observable.

    I would describe both as observations mutually agreed upon by humans from different frames of reference. Note: The other human could simply be you, that mostly agrees with what you are observing.
  7. Mar 14, 2007 #6
    human neurons physically create the subjective qualia of sound through neural connections specifically triggered by signals from the auditory system- the soundness of sound and the blueness of blue are simply the emergent result of chemically modulated neural activity- just like how complex patterns abstractly and unpredictably emerge from a simple cellular automaton - the quality of qualia is an abstract emergence of subjective experience for the brain that has been adapted by evolution to provide information about the environment and the body- evolution could have just as easily wired us to hear colors and see melodies-

    a robot would process the audio information differently but that is not to say that it does not experience some form of auditory qualia [if it is constructed as a conscious agent]- just that it's analogue of sound would be different- and likely only expressible to other robotic minds with the same type of auditory system- human neurons are very complex biomechanisms which produce really very simple binary states at each input/output synapse- all of the complex chemistry in the brain ultimately only results in modulations of the ways in which neural connections fire/ how long they are active/ how many from what bundles are triggered/ how active connections trigger others- but each connection is either on or off at any given time- so the brian is reducible to a system of bits [10^15 ish] and hierarchies of boolean operations which determine how they react to signals- if a robot was programmed with a human-equivalent network of bit-registers with accurate modleing of neurochemistry it would experience the SAME qualia as we do

    'qualia' is just a way of saying that some physical information processing system results in a special class of subjective abstract analogue representations of the signal spectrum for a conscious agent- but some form of qualia is logically required for such a conscious system or there would be no conscious awareness of ANY information

    the nature of qualia has caused centuries of philosophical head-sratching- but the physical process which creates qualia is merely neurochemistry
    Last edited: Mar 14, 2007
  8. Mar 15, 2007 #7
    thanks for the replies everyone. i'm hoping to do a consciousness module at university next year, so i'm sure to have lots of questions!

    setAI- i read your reply; are you basically saying that the brain is more than the sum of its parts? because i guess that's where my confusion lies.
  9. Mar 16, 2007 #8
    in the context here- less- because all of the complexity of the brain reduces to discrete states of about 10^15 bits registers and how they affect each other- totally invariant from the physical substrate- the biological substrate only serves to provide the rules in which signals are processed- and all qualia and consciousness emerge from within them as an interrelationship between bit-states in a network
  10. Mar 27, 2007 #9


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    Dave, the question you ask is essentially the central question of the mind/body problem, which has been a central problem of philosophy since philosophy began. The question can be phrased "what is the nature of the relationship between the mind and brain?" or alternatively "why is it that the physical processes of the brain are associated with subjective experience?"

    Depending on who you ask, this question may not even be amenable to scientific scrutiny. Regardless, it is certainly the case that right now no one really knows the answer. (It is my opinion that scientific methodology could be used to reveal what neural mechanisms are associated with conscious experience, but that the explanation for why those particular mechanisms are associated with experience will only be a matter of one's philosophical preference.)

    You may want to research what has been called the "hard problem of consciousness," as this is how the question is typically framed in modern discussions on the matter.
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