Immanuel Can wrote: ↑Fri Jun 07, 2024 7:02 pm
Easy.
Let's call the BB, or Creation -- whatever you wish to designate it, the "0", the zero-point of the universe's origin.
From the 0 point to the first subsequent event (like the banging of the first two molecules together, or whatever you wish) is +1. The second event after the 0 point is +2, and so on. So we can put the cause-and-effect story together this way: the 0 event caused the +1 event; the +1 event was the immediate cause of the +2 event, the +2 event was the immediate cause of the +3 event...and so on, to the present moment.
But wait: if there is no such thing as an "uncaused cause," then the 0 event was itself caused. We don't even have to know what it was that caused the BB or Creation, or whatever. Whatever it was, we simply mark as the "-1" event. Whatever caused the -1 event, we now call the "-2" event...and so on.
But what does "cause" mean? It means that an event
cannot happen without its cause having existed first. It would be, for example, utter nonsense to say, "I am the child of my great grandson." That's utterly impossible: if you are the grandfather, you can't possibly be the progeny of your own grandson. Likewise, if we say "the gasoline caused a fire," we must mean that before there was any fire, there was gasoline. This is surely frightfully obvious, but we need to make it plain here: a thing can't "cause" another thing, unless it came
before that thing: never at the same time, and never afterward. If it came at the same time or afterward, then it was certainly NOT the cause of the event. Clear enough?
So something caused the BB or the Creation, the "0 point" event, whatever we consider it to be. And that something was the "-1" event. It was caused by the "-2" event...and so on.
So we've got a string of causes that looks like this: -3, -2, -1,0, 1, 2,3,...potentially to infinity, perhaps.
But notice this:
that's only possible at the right-hand end of the string. We cannot have an infinite string of digits to the left of the sequence. And why? Because -3 had to come
before -2, and -1 had to come
before 0, and so on.
Here's the clincher: if the sequence was infinite to the left, that is, "infinitely regressive," then IT WOULD STILL BE WAITING TO BEGIN. When could it begin? Never. Because an infinite chain of prerequisites is required in order to arrive at the 0 event: and infinity, running backward,
never begins.
Thus, if our universe were dependent on a regressing chain of causes, and that chain were infinite, THE UNIVERSE WOULD NOT EXIST. It couldn't ever get started. Its prerequisite conditions would recede infinitely, never finding a starting point.
And you can test it by using the chain we constructed to model the situation. Ask yourself this: if I stipulated to you that you could not write down "0" until you had written "-1" already, and couldn't write "-2" until you'd already written "-3", and so on infinitely,
at what point would you get to put pen to paper? 
The answer, of course, is "never." Just so, there would never be a universe if the causal sequence that produced it had to be infinitely regressive.
But there IS a universe, of course. So that tells you something beyond any reasonable doubt: that the universe is not the product of an infinite regressive chain of cause-and-effect. It had some uncaused causal point. We cannot, at this moment, and without more data, say more than that: but we can say it with absolute certainty.
But can we say more? I think we can. We can start to talk about what kind of an "uncaused cause" is the most plausible candidate for initiating a causal chain that results in the kind of universe we have...and we can move on from there, as well. But this is already a long reply, and it's said enough to establish the certainty of an uncaused cause at the root of the universe. And that's all that was so far asked, so I'll pause here.
