[O]nce space travel begins, there are, in principle, no further physical barriers to prevent Homo sapiens (or our descendants) from eventually expanding to colonize a substantial portion, if not all, of the visible Cosmos. Once this has occurred, it becomes quite reasonable to speculate that the operations of all these intelligent beings could begin to affect the large scale evolution of the Universe. If this is true, it would be in this era—in the far future near the Final State of the Universe—that the true significance of life and intelligence would manifest itself. Present-day life would then have cosmic significance because of what future life may someday accomplish.
John Barrow and Frank Tipler, The Anthropic Cosmological Principle, Oxford, 1986, p. 614