I actually present this argument in the last two chapters of The Cosmic Bridge. I like the message in the old version (1951) version of The Day the Earth Stood Still, which roughly states that if we export our warlike ways to the Universe the Cosmic Civilization will have to act and the result will not be pretty.

There have always been myriad reasons for venturing into a new frontier or what have you. My thought is that in the next few hundred years, physics will advance to the point where we WILL have the ability for starflight. And when some some-one both has sufficient ability and sufficient need to go, then they will go.

Whether or not we deserve to go is a very different question. Humanity has been quite adept at expanding into places we arguably do not deserve to go. Yet, for better or for worse, we went anyway.

There are six-billion humans and counting. Each of us function somewhat independently. Thus, the human race is pretty good at doing lots of things at once. Unfortunately, While those 'things' have often been endeavors with greatly varying degrees of wisdom, they have been done. I believe this shows that humanity will move into a new arena given the capability to do so.

Ultimately, I suspect that the only thing that could prevent us from going to the stars is if we destroy our own civilization - which, IMHO, is a very real possibility. This could mean wrecking the whole Earth, but would more likely "only" mean the collapse our own civilization.

I subscribe to the idea that each species/civilization is implicitly tested at the stage in which they develop large scale energy capabilities (becoming a type 0 civilization, to use Michio Kaku's terminology). In our case, this means nuclear technology and space travel, possibly including stardrive capability. If the species in question (in this case, Humanity) manages to transcend ego and survives to reach the cosmic-era it will probably survive onward for the long haul. For us, that probably means making it through the next hundred or so years. If we manage that, I suspect that we will somehow manage to mitigate our current planetary-scale survival issues.

My own belief is that our destiny is in space, regardless of who we are at the time we go. It is in everyone's interest - Earth and Cosmos together - that humanity has evolved a mature consciousness when we do venture forth.