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.