(September 3, 2012 at 5:49 am)genkaus Wrote:(September 3, 2012 at 4:01 am)idunno Wrote: All right, let's see if the ol' brain is still working at this point. First, of course time has existed for all time. Time obviously can't exist before or after time. What I was asking is if time had a starting point, or does it extend backward infinitely?
I'm saying that your question doesn't make sense - even more so because those are not the only two choices. First of all, the words "starting point" assume a temporal context. Secondly, a circle has no starting point and yet is finite. What you are assuming is a constant linear forward progression, whereas we know that there are places where the progression can actually stop.
(September 3, 2012 at 4:01 am)idunno Wrote: Next, the analogy is meant to put this issue into perspective. The reason I have the guy start from the present wall is because we have a fixed point in the present moment, something we lack in the infinite past (IP). I couldn't say "let's start from the IP and work our way to the present moment" because there is no "point" in the IP to start from. It's infinite. Even if AquaMan had an endless amount of time to reach the IP he doesn't actually reach it. If he were to reach it, it wouldn't be infinite (endless; without end).
And why is that? If he had an infinite amount of time to traverse an infinite distance, why wouldn't he reach it? You're just looking at the "infinite distance" part and not considering how the other "infinite time" would play into it.
What I'm suggesting here is dependent on the A theory of time in which there is a linear progression. The starting point I am referring to is the present moment. Starting from this point in time, if you were to head back to the infinite past you wouldn't reach the end even if you had an infinite amount of time to do so. If you reach the end, in an infinite amount of time, you've not actually gone an infinite distance. If you reach an end point, your destination wasn't actually infinite. I'm repeating myself here but I don't know how many other ways it can be said.
Now Categories+Sheaves has teased about actual infinities so I'm sure he knows what I'm talking about and am interested in what he has to say on the matter.