Look
here: On the principle that theory follows practice, how long before we discover that brains are actually quantum computers. The technology is moving quickly and as researchers tend to find what technologists did a bit earlier, I think a pool is in order, winner take all.
What makes you think it's a quantum computer? We understand very well how neurons themselves work, and they're too macro to be able to be quantum computers. Do you think that there is some much tinier auxiliary system (e.g., a glob of hitherto undiscovered cells that perform some form of quantum processing) that aids it? We don't know any biological processes that rely on QM specifically to work (AFAIK), so that would be a first for quantum biology. It's possible to compute lots of things in less time, using QM rather than a classical computer, but none of those seem relevant to the computational model of the brain, a neural network. QNNs, quantum neural networks, are certainly a thing, but not an important thing. NN computation doesn't benefit much from QM.
ReplyDeleteWhat makes you think I do? I am making a somewhat arch "prediction" based on a jaundiced reading of scientific crowd behavior. Did the cheek poking out elude you?
ReplyDeleteWere your previous remarks about the Gallistel-King Conjecture (i.e. that the brain uses DNA for storing memories) also tongue in cheek?
ReplyDeleteNot really. There is some very mild evidence that this is not far fetched, as you know. There is evidence that memory etc implicates molecular alterations in DNA/RNA structure, see the papers cited in the post where I adverted to this. My understanding (such as it is) is that a quantum computer requires a lot of technology to keep the quantum states from "decohering." Currently this take some pretty fancy technology and it looks like biological systems will be inhospitable to keeping the superpositions from "collapsing" into classical states. At any rate, like I said, I have a very weak understanding of this. However, if you go back to the 17th century and go forward, physiologists have tended to use analogies based on the best available technology. It hardly seems accidental that brains as computers arose in the mid 20th century. I would not be surprised to find people thinking that brains do non classical computations as we discover how to do these artificially and build machines that do them as well. Would you be? Do we know SO much about how brains and minds compute that it is literally inconceivable that this happens? My friends in these areas assure me that we are pretty ignorant about the mechanics so...
ReplyDeleteI wasn't aware of any evidence that memory can cause changes in DNA structure -- the paper you cited was I thought about genetically engineered bacteria being used as computers?
ReplyDeleteTake a look at http://facultyoflanguage.blogspot.com/2012/10/the-gallistel-king-conjecture.html. I link to an NPR paper on memory and DNA. The two guys interviewed, especially the guy at U Alabama Birmingham has done lots of work on this. So there is both technology work showing that DNA is a good basis for memory and some actual neuroscience suggesting that this gets exploited. There are periodic notices of this in the literature that makes the suggestion speculative, but less speculative than the current fanciful "suggestion" re quantum computing. However, as I noted, analogies matter: clockwork universe? Brains as hydraulic systems, brains as digital computers, nets> Why not brains as quantum computers? On the scale of speculations, however, this is bigger than the DNA based speculations noted above.
ReplyDeleteMichael,
ReplyDeleteI'm a little late to the conversation but there is a very small field of 'quantum biology.' Photosynthesis in particular seems to rely on QM-level effects to efficiently transfer energy from electromagnetic radiation to plants: http://www.lbl.gov/Science-Articles/Archive/PBD-quantum-secrets.html
I am as wary as the next person about the potential for pernicious 'quantum woo' pseudo-explanations whenever the topic is brought up, especially in relation to minds/brains. Doubly pernicious since it also places serious theoretical speculation under a cloud of suspicion. (I also note that D-Wave has been the subject of criticism, e.g., from Scott Aaronson--http://www.scottaaronson.com/blog/?p=291).