Is infinity real, or just a concept, since you can always add one to any number?
A viewer asks whether, if infinity does not really exist, you can think of a number to which one cannot be added.
Answer
No, I cannot think of one, and neither can you, and that is exactly why we say there is no such thing as infinity: it is just a concept, the fact that you can always add one to a number. You cannot define that number; infinity is an abstraction, not a concrete thing. Mathematicians will add, subtract, multiply, and divide infinities because they like to play with imaginary numbers, but those are just concepts. It is the same with Einstein's general relativity: someone asked me about gravity as a massive object pulling in spacetime so that space becomes a curved geodesic, and when you ask what is curving, the answer is nothing; they cannot tell you what is curving, they just have an equation, because it is all math. That is how scientists deal with reality, and even dark matter, which they present as if it were matter you could feel, is really all math that has to equal Newton's original equation.