There is no question that for the long term preservation of the human species it is necessary that we develop interstellar space travel. But what is the importance of preserving the human race? Why are humans so special? Is the development of interstellar travel worth the expenditure of extravagant human effort and resources? Is it only our selfish reproductive instinct that drives us to consider human interstellar colonization a long term imperative? Is the human animal form so necessary in the cosmos or is it the coincidental development of human intelligence that is the significant and seemingly scarce component in the universe that warrants preservation and perpetuation? If humanity’s sentience is unusual and scarce it may arguably be worth some great effort to propagate it beyond our solar system.
As an animal we are genetically little different from a dog or cat, even less from a chimp. We are all thinking, feeling, hungry, social, emotional mammals. The obvious mental advantage we have over the others may only be a small step toward some enhanced intelligence. It may be that we are just as incapable of appreciating our own intellectual limitations as your cat may be to understanding your financial situation. Still, in this larger celestial realm, we possess evolved sapiency and, without a higher comparison available, possibly exceptionally so. So it may be of some importance for the future of cosmic intelligence to preserve this rare and useful characteristic of humans.
Yet getting people to an extrasolar planet can be especially difficult. Our living systems have developed in a rarefied environment that makes them unsuitable for long interstellar journeys. Extrasolar planets would likely need extensive terraforming to make them suitable for human habitation. If it is only our intelligence that is important, it would be much easier to download our critical thought processes into a machine that can withstand the cold and cosmic radiation for the hundreds of years required for an interstellar space journey and then have it reproduce (manufacture) itself in a reasonably compliant planetary or lunar environment.
Yet the human animal, along with many other life forms on earth, has been shown to be resilient, adaptive and resourceful in sustaining life. Maybe some form of animal life with greater tolerance for environmental variability and yet incorporating the brain of a human would make a more suitable life form to send to other planets. A genetically engineered, reproducing animal designed for specific planetary conditions could be developed as our intelligent space traveling surrogate.
But what about human consciousness? How important in our cognitive thinking is our physical connection to the world? Is the material interface of our body with the larger world the source of our consciousness? Would it be possible to program our instinctive self preservation along with a compassionate consciousness into either a bio-engineered creature or a machine? Balancing necessary survival instincts against a benevolence towards others can be a tricky act even for fully socialized, earth bound humans. Colonizing space with living humans, who naturally incorporate our interactive mind/body complexity, may be the only way to insure the perpetuation of our adaptive, inventive intelligence while preserving a communal, higher awareness and an abiding consciousness.