----- ... there is a sense of “now” that runs unidirectionally into the future ... ----- This phenomenon has fascinated me for a while now. Consider the experience that everyone has of the flow of time, specifically "the moving now" Now it's now, but now it's a little later and now it's later yet. Pedestrian, yet no one knows how to model what happening so that physics, mathematics, and our own experience don't seem to contradict each other. Like, take the spacetime view of physics, where it all exists at once. But wait — how does that jibe with our experience of our lives as a succession of instants ordered like the real numbers? OK, maybe our consciousness is like the lit end of a fuse, moving along our worldline in 4-space? But if so, this motion seems to assume another kind of "time" through which it happens. So what gives? Another possibility is that our lives are being lived from start to finish, unchangingly. The parts we have already lived as well as the parts we have yet to live, just like the present moment, all entirely as equals. This just leaves unexplained how we can then experience a moment as separate from other moments. So: paradox. —Dan Veit Elser wrote: -----

On Nov 28, 2018, at 11:31 AM, James Propp <jamespropp@gmail.com> wrote:

Julia Robinson has a good quote: "What is proved about numbers will be a fact in any universe.”

This still suffers from the bias that “intelligent life” runs on a platform that is “open” in the sense of physics, where there is a sense of “now” that runs unidirectionally into the future. For example, if some form of life was effectively a closed system, with perfect symmetry under time reversal (i.e. unitary evolution), I very much doubt that questions involving the operations of arithmetic or logic, most of which are not reversible, would arise (be considered interesting). The only work of fiction I know of that brings up this bias is Vonnegut’s Slaughterhouse Five, in which the Tralfamadorians have managed to become “unstuck in time”, that is, they experience the events on their world-lines not in sequence but as a single entity. We have the means, in principle, to build new kinds of AIs that are not subject to this bias. Whether there is anything interesting to talk about with them, or whether there is even a sense in which we could carry on a conversation, is another question. -----