First off, I want to alert you to some of the other bloggers covering the Nature of Time meeting. Over at Cosmic Variance, conference co-organizer Sean Carroll describes how the the meeting was conceived and has posted his introductory slides. Meanwhile, Sabine Hossenfelder has been pondering whether AI will eventually cause the extinction of humans.
On a related note, if you've ever worried that you might yourself be an automaton, rather than a truly free being, then computer scientist Scott Aaronson is the man to visit. He opened this morning's session on "Quantization" by presenting a fresh perspective on free will and quantum mechanics, with what he promised would be the "looniest" talk he had ever given. (Aaronson: "I'll place a much higher premium on being original and interesting than on being right. (I got tired of being right!)")
With the qualification that the quantum-free-will arena is a notoriously "bulls**t-strewn interdisciplinary field," Aaronson turned to computer-science prophet Alan Turing for inspiration on how to clear the stench. The Turing test arose after Turing replaced his initial question, "Can machines think?" (which he quickly decided was meaningless) with the answerable question: "Are there imaginable digital computers which would do well in the imitation game?" Aaronson proposed a similar "replacement" question to help get to grips with the problem of free will. Just as the Turing test has led to a focussed research program in artificial intelligence, might articulating the free will problem in a more refined way lead to a focussed program in neuroscience?
Aaronson began by specifying that he takes one necessary condition for free will to be (partial) unpredictability - "not by a hypothetical Laplace demon, but by actual or conceivable technologies (DNA testing, brain scanning...)." He then defined his "envelope argument": Imagine being handed a sealed envelope, containing predictions made using an artificial model of your mind based on some advanced future technology that could scan your brain in incredible detail (for instance). You answer a question and upon opening the envelope you find that it contains the words that you had just said. That, says Aaronson, would come pretty close to an "empirical refutation of free will." If such an envelope could be made and someone could predict all your actions (or, at least, correctly predict a significant proportion of the answers you would give to a set of questions) then you'd be "unmasked as an automaton, much more effectively than any philosophical argument could unmask you."
If the thought of being revealed to be an automaton by Aaronson isn't enough to scare you, then physicist Geoffrey West's apocalyptic view of the world seen through the lens of complexity theory should. This month's Scientific American has an article about his work analysing the social and economic activity of cities and he had some sobering words about the unsustainability of growth. Basically we're all doomed (but he said it more colorfully).
[youtube: DFFVSvAr7Wc, 560, 340]
Bringing the whole thing back to time, West also proposed that a notion of "universal time" emerges when you think about the "pace of life" and look at the lifespan of mammals not in terms of years but in terms of heart beats (which, in turn, is related to metabolism and the production of ATP). Apparently any species, regardless of size, has approximately the same number of heart beats in its lifetime (roughly 1 billion). Measure time by beating, says West, and maybe the shrew that lives for a year and the whale that lives 150 years have the same "experiential lifespan." It seems Sammy Davis Jnr was right; it's all about the rhythm of life...
(Photo courtesy of Olaf Dreyer.)
(Edited on 21 October 2011 to include Geoffrey West's video.)