Infinity

This topic has been flirted with in the "Why are people Atheists?" thread, but I feel like it deserves its own thread, partially because I don't very much understand infinity, and I doubt many others do either.

To start off, I have heard numerous times that an infinity of this and that is an absurdity. At the risk of this being a very quickly resolved topic, I have to ask why, and what the reasoning behind this is.

Infinity itself is not necessarily an absurdity, but having an infinite amount of many things can be.

So, if an infinite amount of time must pass before the present (to use an example for the atheism thread) then we could not, in fact, be in the present, because an infinite amount of time cannot pass.

I'll give an example of an infinity number of things which aren't absurd, if I may: "there is an infinity number of numbers".

But saying infinity number of apples would be absurd.

Not necessarily.

In a finite universe (as ours is), then yes, it is absurd.

But not in an infinite one.

Also, a line segment of one meter is constituted of an infinite number of points.

So, if an infinite amount of time must pass before the present (to use an example for the atheism thread) then we could not, in fact, be in the present, because an infinite amount of time cannot pass.

Isn't time just another dimension, though? It's not like time really passes. What makes it less plausible than, say, an infinitely large plane of space?

You can have an infinite amount of time existing, but you cannot have an infinite amount of time passing.

Just like you can have an infinitely long road, but you can never have anyone at the far end of it.

Originally Posted by GDwarf

You can have an infinite amount of time existing, but you cannot have an infinite amount of time passing.

But that's just the thing. Who said anything about time passing? It is just another dimension. An infinite past is no less plausible than an infinite future.

An infinite past can exist, but if it does the present in which an infinite amount of time is behind you cannot.

Why? Because you cannot reach the present, since to do so an infinite amount of time would have to pass, which cannot happen.

Because you cannot reach the present, since to do so an infinite amount of time would have to pass, which cannot happen.

As you might have gathered from my previous posts, I don't agree with the notion that time literally passes from one end to another. We simply have that idea because of how the brain works.

In this sense, what you say would be akin to taking a theoretically infinite line, picking a point and showing that the line cannot be infinite because we would have to have traveled an infinite length to reach this point. Yet, traveling was not really necessary.

Of course, not knowing a great deal about time, I can't say how sure I am of this theory.

Ah, but what if you had to travel down that line? Then, yes, you would have a problem if, at any point, you stopped and said: "I have covered an infinite amount of distance to get here."


Time is something that does pass, it's another dimension that's essentially the same as length, width, or height. If you can reach the end of an infinitely long ladder then, and only then, could you come up with justification for an infinite amount of time passing before an event that has happened.

in a mathematical environment the concept of infinity is a necessity.

GDwarf, my point was that time doesn't "pass". What exactly, specifically, does this concept denote? And what is present to justify this? We seem to be in agreement with everything except this.

Though I find myself somewhere on an infinitely long ladder, this does not instantly mean that I must have climbed from its bottom.

Isn't the modern consensus in physics that we live in a universe that truly is infinite? Such as when viewing galaxies that are farther away are red-shifted even more than galaxies that are closer. But as far as I know, there is no definite center of the universe so we just assume it's infinite. If anyone could shed some light on why we view it's infinite, that'd be infinitely helpful. (forgive the bad joke )