Philosophy Time
So, as part of the weekly physics lecture series at the University of Queensland, we had a talk on Friday from a philosophy lecturer, talking about the philosophy of time. He was asking questions like, does time flow? Does the past and future exist? And how are these theories if, as general relativity theoretically permits, we think about “closed time-like loops”? That’s where you basically allow for time travel, in some “consistent” way. For example, I find plans for a time machine on my desk, decide to build it, discover it works, and then travel back in time to put those prints on my desk for me to find. Who actually made the plans?! Einstein’s theory of general relativity (and I don’t know too much about this, actually) allows, at least in principle, for such things to occur - but I’m not really sure of the details.
I went in the hope of an interesting lecture on the nature of time, implications for the universe, and so on. I have to confess, however, I was quite disappointed. In contrast to David Chalmers talk on The Matrix, which was rigorous and very logical, I found that the philosophy presented here was more of semantics and language than of real substance. What does it mean for the past to “exist”? How do you define “now”? If you say “only the present exists”, what are you implicitly assuming doesn’t exist? I confess I really couldn’t follow much of the talk - I just wasn’t up on the jargon - but I really didn’t see how any of this contributes to our understanding of the universe, or consciousness, or our minds.
As one questioner pointed out, none of the predictions of these theories could be tested, or would ever produce “different” outcomes in experiment. In fact, that means they’re not theories in the scientific sense, any more than theories of “intelligent design” (a supreme being/god/alien guided our evolution) because if you can’t test it, it’s not scientific. Sure, we’re producing theories of physics which we can’t test - yet. The key is that, in principle, you could test them - and we’re already working toward the next generation of equipment which can help confirm (or, even more exciting, disprove!) our cutting edge theories.
Basically, I guess I can’t see the point in this sort of research. I’d welcome some debate from philosophers, but it really seems a bit “wishy washy” - I want to see some meat! Some definitions! Maybe that’s just the physicist in me, though. That’s why I liked David Chandler’s work - he had real definitions, real conjectures, and really worked with it.
Anyway, two final neat things: we had our obligatory wacky question (along with condescending remarks to students), and I got again to hear philosophers’ habit of saying “sympathetic”, meaning (I think): “I understand where you’re coming from; you’re wrong, but I do see your point of view”. It’s usually in the context of “I’m sympathetic towards Bob’s Theory of Everything, but…” or “I’m sympathetic with people who have trouble believing Jane’s Axiom, but…”! 
Dee Says:
I remember that lecture well. I found it rather tedious. But my analysis of the content was a little different from yours. I remember picking up hints that led me to believe that the field being discussed had been founded by logical, sensible sensible people with clear points of view before the debate was taken over by people arguing without understanding.
There were a few interesting questions which were touched on, then mentioned no more. For example, at one point in the talk, the speaker touched on the question of whether different people experience time at the same rate. He introduced the notion of A-time and B-time, one of which was time in the physicist’s sense of the word, and the other being subjective time, as experienced by a given person. That’s not something that’s completely unscientific. We may not be able to measure it at the moment, but it’s conceivable that at some stage we will be able to.