I was reading the answers by some scientists (including Krauss) to the question "What do you believe but cannot prove" on edge.org, who say there are good reasons to believe the Universe is infinite. They don't mention what those reasons are, but I was wondering if somebody could comment on that. Besides the anthropic principle, which I'm not even sure is popular among scientists, I'm not aware of any other compelling reasons. I also presume they're not talking about unbounded universe. Thanks, Pavel.