(February 14, 2018 at 10:56 am)Grandizer Wrote:(February 14, 2018 at 10:48 am)SteveII Wrote: So, when you said there was such a thing as completed infinity of events, you are talking about real objects. Your justification is that mathematics has a useful (on paper) abstract concept like considering all of the natural numbers--which cannot be counted--as one thing. You don't see the difference?
Not just natural numbers, but all integers. And all real numbers as well.
What do you mean by cannot be counted as one thing? I'm not asking you to count anything. It's there, already complete.
Provide a logical argument against actual infinity existing in reality, if you think there is a logical problem. Saying "married bachelor" is not good enough because we already showed you it's not the same thing.
Hilbert's Hotel:
Imagine a hotel with a finite number of rooms. All the rooms are full and a new guest walks in and wants a room. The desk clerk says no rooms are available.
Now imagine a hotel that has an infinite number of rooms. All the rooms are filled up so an infinite number of guests. A new guest walks up and wants a room. All the clerk has to to do is to move the guest in room #1 to room #2 and the guest from #2 to #3 and so on so your new guest can have a room #1. You can do this infinite number of times to a hotel that was already full.
Now imagine instead the clerk moves the guest from #1 to #2 and from #2 to #4 and from #3 to #6 (each being moved to a room number twice the original). All the odd number rooms become vacant. You can add an infinite number of new guests to a hotel that was full and end up with it half empty.
How many people would be in the hotel if the guest in #1 checked out?
If everyone in odd number rooms checks out, how many checked out? How many are left?
Now what if all the guest above room number 3 check out. How many checked out? How many are left?
So from the above we get:
infinity + infinity = infinity
infinity + infinity = infinity/2
infinity - 1 = infinity
infinity / 2 = infinity
infinity - infinity = 3
Conclusion: the idea of an actual infinite is logically absurd.