Or, how I understand infinity to work, as a person who isn’t particularly knowledgeable about science.
I’ve read some books, most recently The Mathematical Universe, and come to think of it, I did watch a Netflix documentary about infinity once. But my key assertions – or at least the things I believe to be true – are just some guy thinking about it. I am not an expert, as I’m sure the following paragraphs will make clear.
I think a lot of people struggle with the concept of infinity because they think it means “a really big number.” But it means something closer to “everything.” The difference between “a really big number” and “everything” is, well, everything. So when people talk about infinite universes, they’re not saying “a vast number of universes that are always expanding.” They’re saying “if it can exist, it does.” Which is mind boggling.
Multiverse theory has never sat well with me, placing me in good company. Everyone, whether they agree with the theory or not, starts from a place of “huh? How could that be true?” Max Tegmark describes how physicists sometimes move from “I hate it and it’s wrong” to “I hate it.” So I’m hardly alone in thinking the theory sounds insane. The only difference between me and really smart physicists is that they’ve done enough research to truly hate it, whereas I’m just a normie struggling to understand the basics.
All of which to say, I’m not claiming I’m right or have any unique insight into the question, just that I’m as befuddled as you’re supposed to be when you start thinking about this. So let’s talk about infinity in the context of multiverse theory, and what “everything” has to mean.
Is it possible that there’s a universe where you’re exactly the same as you are right now, but in five minutes you just randomly sprout a tail? Even if this has never happened to anyone on earth, ever? Well, probably not. We’re still bound to the laws of nature, and the idea that a person would spontaneously just get a tail isn’t something we’ve seen before. So that universe almost certainly doesn’t exist because it bumps up against the laws of nature and physics.
I was talking to a friend yesterday about universes where I am married to a frog or Barack Obama. Are those possible, even if the chances are very very low? Of course, because very very low is not the same as impossible. Just like very very big is not the same as infinite. Multiverse theory and infinity – according to my lightly educated understanding of them – claims that everything that can be possible is possible. Marrying a frog or Barack Obama are extremely unlikely, not impossible, which means it exists. On the other hand, 1+1=3 will never be true, anywhere, under any circumstances.
That’s how I understand it, anyway. I could be wrong. Or the theory could be!
Fun side note: in 2006 or 2007 I was invited to meet the junior senator from Illinois for a small brunch gathering in Seattle. I could have gone, but I assumed he had no chance at the presidency so I passed. But multiverse theory tells me that other versions of Jon Bell met Senator Barack Obama that day. It tells me that of all the versions of myself, some ended up striking up a conversation with him. Of those, some subset made an impression on him, and yes, some subset made such an impression that we became friends. Extrapolate from there.
The difference between verrrrrrrrrrrrrrrrrrrrry unlikely and impossible is where infinity asserts itself. Do I honestly think there’s a version of me somewhere in the multiverses who is happily married to Barack Obama? Well, no. But some versions of multiverse theory claim that until I can explain why it’s breaking the laws of physics, that reality does exist out there somewhere in the tapestry of infinity. Kind of strange, but I am sure – and I can admit – the chances of that reality existing cannot be zero.