There are a great many ways of dealing with infinity (or infinities) in mathematics. In some of those ways of dealing with them, it’s a number, and in others, it’s not. In some, it’s meaningful to speak of things like “infinity +1”, and in others, it’s not. And it’s not even really meaningful to speak of which of those systems is most commonly used, because in the most common use, people don’t deal with infinities of any sort at all, and so none of the ways of dealing with infinity matter.
You’re taking as a premise that there are no infinities in the Universe, and then using that to prove that there are no infinities.
I’d like to counter that it’s quite evident that there was a beginning of time - or at least a thing that came into existence without something prior. Everything that exists or has existed has an age. If there is a god with perfect memory, it remembers all its birthdays - a specific count of specific events. If the god lacks perfect memory, it still had birthdays - a specific count of them. Everything actualized has an age. That includes the universe.
It’s worth noting that this proof only goes in one direction - as something gets older, as it actualizes more years, there’s no reason to claim that that will ever end. It could exist forever - but at any given time, it’s only existed for so long.
That’s part of what’s up for debate. You mention birthdays, so we would have to specify some sort of unit. Let’s say we’re measuring in Planck times. I assume it’s safe to say that at some point in the past that the universe was 2 Planck times old. Half that and it would be 1 Planck time. Can we half that and conceive a universe that was 1/2 Planck time old? What about 1/4 Planck time old? What about if we’re not dealing with the very beginning but some later date. Does being 100.25 Planck times old make any more or less sense than being 0.25 Planck times old?
But no, this I don’t accept. Okay, we have no good vocabulary to talk about things outside the flow of time that we’re accustomed to in our universe, but in a deeper sense I don’t accept that it’s reasonable to believe that there was some “prior” state in which there was nothing rather than something. Some set of laws and circumstances gave birth to our universe. And I think it’s more natural to accept that it’s turtles all the way down, than your claim that we could in principle reach a bottom turtle standing on nothing.
Planck times seem to be indivisible, as I understand it, so no, it seems they can’t be divided. (Not that I understand why you’d want to or why it helps - the thing still didn’t exist 3 Planck units previously either way.) And no, fractional Planck times don’t make sense, again by definition, but again I don’t see how that helps. 101 Planck units old is not the same age as 1 Planck unit old either way.
Things that exist have histories about the time they existed and have ages which, in turn, means that no existent thing has an infinite age or has existed forever. I don’t see how it makes any real sense to dispute that.
Similarly, your stack of turtles has a history and, therefore, an age. Turtles have been regularly added, and each new turtle being added was an event.
Seriously folks, what’s the big deal about the universe having popped into existence out of nothing? Quantum mechanics was mentioned earlier. It’s my understanding that when you starting getting into that subject, stuff is popping into and out of existence all the time.
It’s part of the nature of infinity that I’m curious about. Sure, we can talk about the extremes like infinitely young or old. But we can also talk about infinities in the middle that avoid the issue of dealing directly with Big Bangs and Big Crunches.
It’s delicately balanced on a bad analogy, I gather.
That, or as you follow your way down the stack the turtles get simpler and simpler until they’re just clumps of cells and then clumps of particles and then a single particle and then nothing.
Time travel is fun and all, and sounds like a good solution, but then you find yourself asking there’s a floating loop of turtles instead of no floating loop of turtles and you’re right back where you started.
I don’t understand this even as a joke. Georg Cantor proved there was an infinite number of infinities in math when he developed set theory and the basic understanding of infinities.
It’s nothing to do with time travel. I’m saying that given that this universe exists, it’s reasonable to believe that some set of laws/circumstances gave rise to this universe, “preceded” it. For any configuration of something rather than nothing, that’s always true. Every turtle is standing on the back of another turtle.
That to me seem far more natural than your assertion without evidence that somewhere there must be a boundary, that at some point there was nothing rather than something, and something rather than nothing just popped into existence, a turtle standing on…?
I was specifically answering the supposition that the ‘bottom’ turtle might be standing on the ‘top’ turtle. Unrolling the analogy, that would be if the universe was started by somebody from the future time traveling to the beginning and setting off a bomb or saying “Let there be light” or whatever. This has been done in fiction a number of times.
On the subject of assertions without evidence, this one seems to directly contradict some things I vaguely recall learning in school. Quantumy stuff, and such.
That’s one of the reasons I like the story so much. Because aside from the turtle and flat Earth aspect, there are deep questions there. What is the problem, exactly, with infinite regress? And if there is no infinite regress, what exactly is the alternative? In some ways, the (apocryphal) turtle lady was more insightful than her incredulous opponent.
You’re recalling the stuff that Krauss talks about here:
He discusses how a set of laws can “spontaneously” give rise to a universe. But the very fact that those laws govern anything is a something. Krauss doesn’t address the deeper sense of something rather than nothing.
That gets into the debate of the definition of “nothing.” I think English comes up short, using the same word for more than one concept. I’m not sure if any other languages do better in this regard.