Who here believes in the Many World Interpretation? Why or why not? So they believe in a real, physical infinity, as opposed to a mathematical infinity? I thought infinities in physics meant there was a problem with the theory requiring revision. — Marchesk
Infinite space? Of course. Whether it's "real" and "physical" is down to semantics, I guess*. But the idea that space is infinite is old and, I would think, much less controversial than its opposite. We only got a good grip on the latter concept (of finite space) recently, with the development of topology and modern cosmology. Otherwise it is rather hard to imagine, intuitively.
I forgot which ancient Greek philosopher it was that argued that space must be infinite, because suppose that it rather had a boundary; then on reaching that boundary you could just poke a stick through it.
* But if you think that space is somehow not physical or not real or doesn't count for some other reason, well, once you suppose that space is infinite, it is only natural to suppose that there's an infinite amount of stuff in it - stars, galaxies, etc. - and that's as real and physical as it gets, right? The alternative would violate the Copernican principle, making our finite pocket of the infinite universe very special for no good reason.