Thinking About Infinity. Check My Math.

I have been thinking about infinity.

I was never good at math in school but I have always been fascinated by numbers. Here is what I have been running through my thoughts. Check my math.

infinity + 1 = infinity, which makes it seem like that 1 is a zero – no effect.

What about infinity minus 1? It has to be less than infinity. Right? So, what is the answer?

infinity + infinity = infinity

But infinity – infinity = 0

Two things inspired this infinitely frustrating thought experiment. First, I watched the film A Trip to Infinity (on Netflix). This 2022 documentary explores the concept of infinity through interviews with mathematicians and physicists.

The second inspiration was the much lighter sitcom Young Sheldon. In a recent episode, the precocious and young genius Sheldon comes to doubt the existence of zero. He is tutoring his not-very-bright neighbor Billy in math. During the session, Billy naively asks how zero can simultaneously exist as something but be nothing. The question causes Sheldon to have a kind of existential crisis. He turns to the two professors he works with and they can’t really answer the question and have some mathematical doubts too. It’s not unlike the physicist and mathematicians in the infinity film who have answers about defining infinity but don’t really agree or even seem very confident.

Sheldon rejects religion and God which is very important to his very Christian mother. Somewhat incongruously, when Sheldon talks with Billy again, Billy suggests they just pretend zero exists. Sheldon interprets this as an act of faith and that restores him.

It’s not that you can’t find a definition of “infinity.” It is that which is boundless, endless, or larger than any natural number. The ancient Greeks discussed the philosophical nature of infinity. In the 17th century, we get the infinity symbol and infinitesimal calculus. Working in the foundations of calculus, it was unclear whether infinity could be considered as a number or magnitude and, if so, how this could be done.

By the end of the 19th century, people were studying infinite sets and infinite numbers, and infinity was clearly a mathematical concept. In physics and cosmology, whether the Universe is infinite is still an open question.

There is a section of the film that I rewatched and it still doesn’t make sense. One physicist says that if you place an apple in a box it will decay into mush and then dust. Then, it becomes microscopic particles and then it becomes one with the universe. Whoa. Give it enough time, and it will become an apple again. What?

I think the connection between the film and the TV episode is the futility of wrestling with paradoxes. You probably will end up accepting that with all of our knowledge we will likely never explain or comprehend the greater existential realities of the universe.

Aristotle said that the more you know, the more you realize how much you don’t know. Not that we shouldn’t think about these things. Just don’t expect an answer.