I'm not sure I understand what you're saying. I can imagine a lot of things that don't exist in our universe, from magic flying ponies to Cthulhu. Some of those things are physically impossible; and yet, this imagination still takes place in my physical brain... Doesn't it ?
That wasn't my point. Whatever you are imagining has to be represented in your brain even if it is a phantasy. Can you imagine an infinite set in your brain? I'm not talking about the concept of an infinite set, but an actual infinite set?
Here's the new thread for posting quotes, with the usual rules: