From a thread in "Existence of God," a poster named "Random Person" said,
If the universe was eternal, then this moment would never exist. An infinite number of moments would still be unfolding prior to now.
Time happens chronologically. If an infinite number of minutes had to pass before this moment could occur, then this moment would never arrive.
More description of what I believe is his proposed argument is in this post.
Asking this question in mathematics for his benefit:
What are the mathematical principles that make this argument true or untrue?
I believe myself that this is a very good and legitimate point. I don't buy it, but I sort of understand that people should feel aggrieved by the notion of an infinite past. So, there's no use dismissing this argument. We need to find the proper answer.
So, let's assume the past is infinite. Because it's more convenient for discussion, we can also assume there's a beginning to time. This bit may sound contradictory with the notion of an infinite past but that's not the case at all. We could assume there's no beginning but no beginning is even less intuitive than an infinite past. So, the argument above could be framed a bit more explicitly. Suppose we have a techno civilisation that developed
after a finite interval from the beginning of time. Scientists there decide to start counting time using atomic clocks, setting the clocks so that the zero corresponds to the beginning of time, assuming they know broadly how much time has elapsed since the beginning of time. An infinite past means that we ourselves are assumed in this scenario to be alive after an infinite interval of time has elapsed after the beginning of time. So, if we could retrieve the clocks set up by this techno civilisation, and assuming they would still be working, we would have to expect that the clocks have run for an infinite amount of time before today. Suppose this civilisation was really ingenious and found a way to ensure that the clocks keep counting and somehow register
every second of time since the beginning of time. Then what indication of time could the clock possibly show today? I guess it would have to be somehow that an infinity of second has elapsed since the beginning of time. But how is it even possible to display such an indication and keep counting in a meaningful way?
OK, that doesn't work and I think that's broadly the equivalent of the perspective Random Person has on the problem of an infinite past. If the past is infinite, how is it possible to start counting at or near the beginning of time and get a meaningful indication today even though an infinite amount of time would have elapsed. We could also imagine that the civilisation I assumed existed at some point near the beginning of time would have continued to exist and develop up until now. These people would have kept records of their past throughout but how could it be possible to register events throughout an infinitely long past? It would have to be an infinite amount of data. How do you even manage that?
Another way to simplify the scenario is to imagine somebody waking up at the beginning of time and in such a good health he would still be alive today, having lived already an infinitely long life. He certainly wouldn't be able to remember his own life, even a tiny part of it, like say just one event every million years, because after an infinite life he would have to remember an infinite number of such events and no brain could possibly do that.
Still, let's grant forgetfulness. The problem for Random Person, I guess, is when we try to imagine this "immortal" going through every moment of his life since the beginning of time. It's easy enough to imagine him doing it for a few minutes, a few hours, a few years, perhaps a few centuries. But even a few millions of years wouldn't be enough. We would need to imagine an infinity of moments of his life and we're unable to do that. We are finite beings so, although we can
conceive of infinity, we cannot imagine it.
So I think the bottom line is that Random Person (and untermensche, of course) wants to be able to imagine going through an infinity of time to accept that such can exist. And unlike conceiving of going through an infinity of time, imagining going through an infinity of time would require an infinity of time, something we don't have. The argument I think is literally to imagine that you're setting a clock at zero at the beginning of time and you're asking people to imagine looking at the clock as it counts time, and this from the beginning of time to today, which would be an infinity of time. And we can't do that. We couldn't possibly do that.
So, I would say myself that some people may be suffering from some quirky cognitive preconception bias that stops them from accepting that conceiving of an infinity is legitimate and good enough in itself so that you don't need to think you'd have go
you yourself through the infinitely long process of
actually imagining every moment of you observing a clock from the beginning of time to today. So, it's a quirk. A frame of mind. A perspective. A different kind of rationality. Neanderthal-still-with-us sort of thing. And we should celebrate this rather than throw our shoes at them. They can't understand something. Let's not do the same thing. Let's try to understand them.
Because they have a point. We can't imagine this process. And we're also used to think in terms of a finite past. Our own lives and our own pasts are all finite. Any period of time we can imagine is finite. We can't imagine an infinite past.
Still, they probably accept the idea of an infinite future. Random Person possibly, and untermensche certainly. The difference is that there's no necessity to think the whole infinity of it. We just think in terms of starting from now and going on for ever without actually having to think the end of time itself. We usually even assume there's no end of time.
Clearly, we think in those terms just because we remember our past lives, most of it anyway, but couldn't possibly remember our future. And we're certainly not going to think in terms of our own dismissal from this Earth. We don't want to think in terms of a specific time when our lives would end. So we think of the future as time without end. That's our default concept of time because we know when we were born but we don't know when we're gonna die. That's just a quirk of our mind. A bias. We all, or nearly all, have it, I think. And apparently, some people don't and can't accept that "conceiving" should be good enough. Perhaps another quirk.
So, there's no convincing them. They can't, they're unable to conceive the idea most people can conceive without any apparent difficulty. Most people accept this idea. Some don't. Maybe it's the DNA that's different, or something else.
Still, I think we should recognise that we ourselves also can't do the "imagining" trick. We have to rely on "conception", abstract thinking, to get a result we accept as good enough and get at infinity. And so we should do well to remember that there's a whole school of thought that's behind this attitude, namely Constructivism, or at least some of it, which seems to ask us to actually imagine infinity, the whole of it, or find someway to construct it, if we are to accept it exists at all.
Maybe it all comes down to accept or not that we are finite beings. Let's also remember that all those people around here who seem to reject Rationalism as somehow in contradiction with their beloved Empiricism can only reject the concept of infinity since infinity is something we definitely could not possibly empirically verify that it exists. Not even that it
could exist. So, here we must have fromderinside and a few others around here joining with untermenshe and Random person to reject the possibility of an infinite past.
OK, I'll come clean. I was trying to do an infinitely long post, just to set a record, but I won't make it. I will have done my best to prove infinity could exist. I can't. Point taken, then.
EB