Okay, I can't entirely resist it! In the physical world we do only have experience of large finite. But I would say that even a child of around 4 to 5 soon develops a concept of unbounded: is there a biggest number? What is beyond the stars? Now, to formalise this basic concept of unbounded into something as precise as the mathematical definition of infinity was a huge step that we only achieved very recently (cf Cantor) but I think the basic concept is probably as ancient as humanity itself.


Now, back to the problem ...