Field of Science

Physicist Ed Witten on consciousness: "I tend to believe that it will remain a mystery"

Here's a very interesting video of mathematical physicist Edward Witten - widely regarded as perhaps the most brilliant mind in the field of the last fifty years - holding forth on consciousness (the relevant part begins at 1:10:25). 

Many people regard consciousness as the last nut to crack at the frontier of science. If we crack that nut it would open the way to an unprecedented understanding of humanity that may in part explain why mankind produces thinkers like Ed Witten that allow us to understand the deep secrets of the universe.

But Witten is not too optimistic about it. And he seems to have fairly clear reasons for believing that consciousness will always remain a mystery. Here's what he has to say (italics mine).
"I think consciousness will remain a mystery. Yes, that's what I tend to believe. I tend to think that the workings of the conscious brain will be elucidated to a large extent. Biologists and perhaps physicists will understand much better how the brain works. But why something that we call consciousness goes with those workings, I think that will remain mysterious. I have a much easier time imagining how we understand the Big Bang than I have imagining how we can understand consciousness... 
Understanding the function of the brain is a very exciting problem in which probably there will be a lot of progress during the next few decades. That's not out of reach. But I think there probably will remain a level of mystery regarding why the brain is functioning in the ways that we can see it, why it creates consciousness or whatever you want to call it. How it functions in the way a conscious human being functions will become clear. But what it is we are experiencing when we are experiencing consciousness, I see as remaining a mystery... 
Perhaps it won't remain a mystery if there is a modification in the laws of physics as they apply to the brain. I think that's very unlikely. I am skeptical that it's going to be a part of physics.
Later on he talks a bit about Roger Penrose's thesis on why we could never build an AI simulating the human mind, and why we may need a modification of the laws of physics to account for consciousness: Witten personally disagrees with the latter stance. I am partial myself toward the belief that we may not understand consciousness simply because you cannot truly understand a system which you are already a part of.

But what Witten is saying here is in some sense quite simple: even if we understand the how of consciousness, we still won't understand the why. This kind of ignorance of whys is not limited to consciousness, however. For instance among other things, we don't know why our universe happens to be the one in which the tuning of the fundamental constants of nature is precisely such that it allows the evolution of sentient human beings which can ask that question. We don't know why the elementary particles have the masses that they do. We don't know why the eukaryotic cell evolved only once.

It's interesting to contrast Witten's thoughts with John Horgan's "End of Science" thesis. In that case Horgan is really saying that the fundamental laws of physics have been largely discovered. They cannot be discovered twice and they almost without question won't ever be fundamentally modified. But Horgan's thesis applies in a larger sense to the whys that Witten is treading on. The end of science really is the end of the search for final causation. In that sense not just consciousness but many aspects of the world may always remain a mystery. Whether that is emotionally pleasing or disconcerting is an individual choice that each one of us has to make.


  1. Quantum physics discovered that wave forms exist is all possible states until they are observed by a conscious organism, instrument, etc. In the case of a scientist observing a particle, his consciousness is not confined to the neural network of his brain, it affects the particle at a distance. "Observer" is not defined in quantum theory - it can be an animate or inanimate entity possessing "awareness" of some sort, the defining characteristic of consciousness. Which leads one to believe that consciousness is both non-local in that it is not confined within the observer, and also pervasive throughout a universe comprised of innumerable aware "observers".

    1. "...scientist observing a particle, his consciousness is not confined to the neural network of his brain..." This statement may or may not be true. For many in neuroscience, adequate evidence exists that consciouness if a creation of the neural network.

    2. Quantum physics states that it is true. The conscious observer does affect a wave form physically separated and distant from the workings within his cranium.

    3. A Geiger counter collapses the wave function just as well as a conscious observer. I think it's more measurement than it is consciousness.

  2. Consciousness will never be explained by science. But science will eventually be explained by consciousness. Consciousness comes first. The material universe does not exist. Period. But scientists can never accept this. Even though their physics has reached an impossible cul de sac, with hundreds of theories of everything not one of which can be proved or disproved. With quantum behavior indicating that nothing exists until observed, thus invalidating itself. Science needs to get off its podium and pay homage to consciousness as the ultimate nature of reality.

  3. For the spiritually-minded person, these are not really hard questions. Once one leaves behind the fancy that the limits of scientific inquiry are the limits of reality, then it becomes easier to think clearly. Witten is obviously smart enough to understand this. Science, that is, the mere study of the physical environment, works extremely well when a limited frame of reference is defined. In an unlimited frame of reference, the physical world can in no way account for its own causation, and consciousness is very similar. There is something about the subjective experience of consciousness that intuitively places it beyond any conceivable causal explanation on the basis of neurological structures and processes. I could be proven wrong, I just can't imagine how. Perhaps this is merely a personal shortcoming, but except for "we'll figure it out someday," which implies foreknowledge of future events, I haven't heard anything solid yet.

  4. If you define an observer as an animate or inanimate entity that is aware of its surroundings than an instrument might be considered conscious, though in an entirely different way than a human being experiences consciousness.

  5. If you say "consciousness will always remain a mystery," your mind has no stress. However, even hard problem should has other viewpoints. If you can think of consciousness with 'unit qualia', you would proceed with another one step of understanding consciousness.

  6. Mr. Witten is right that consciousness will remain a mystery. Certainly the classical scientific concept is that consciousness is based on a highly complex representation occurring in the material brain. A simple and popular analogy are the bits, bytes and symbol transformation in a computer. This representation, in turn, could then be described in terms of biochemistry, physics, quantum mechanics, etc... But that unfortunately leads to a paradox, namely that if the essence of our consciousness really is a representation inscribed onto matter/energy in the form of brain processes, then that very representation must lead to another representation, and another and so on, which leads to an infinite regression of representation and never reaches the home base of comprehension. Therefore the idea that material processes are the basis of consciousness leads to a major and unsolvable paradox and an infinite regression. Unless, of course, our understanding of matter/energy is upgraded to something quite different.

  7. Einstein showed that time - the 'present' - is a function of a conscious observer. QM implies that particles - with specific position and momentum - are also an observation, not a fundamental reality. How then is it possible to talk about consciousness as being a result of a brain 'process', when the very word 'process' implies particles moving in time? Process supervenes on consciousness, not vice-versa. Any reductionist explanation of consciousness is bound to a 19th century view of reality.


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