The vast distances that separate the stars are providential. Beings and worlds are quarantined from one another. The quarantine is lifted only for those with sufficient self-knowledge and judgment to have safely traveled from star to star.
Carl SaganWhat distinguishes our species is thought. The cerebral cortex is in a way a liberation. We need no longer be trapped in the genetically inherited behavior patterns of lizards and baboons: territoriality and aggression and dominance hierarchies. We are each of us largely responsible for what gets put in to our brains. For what as adults we wind up caring for and knowing about. No longer at the mercy of the reptile brain we can change ourselves. Think of the possibilities.
Carl SaganImagine we could accelerate continuously at 1 g-what we're comfortable with on good old terra firma-to the midpoint of our voyage, and decelerate continuously at 1 g until we arrive at our destination. It would take a day to get to Mars, a week and a half to Pluto, a year to the Oort Cloud, and a few years to the nearest stars.
Carl SaganI believe our future depends powerfully on how well we understand this cosmos in which we float, like a mote of dust in the morning sky.
Carl SaganWhat does it mean for a civilisation to be a million years old? We have had radio telescopes and spaceships for a few decades; our technical civilisation is a few hundred years old ... an advanced civilisation millions of years old is as much beyond us as we are beyond a bushbaby or a macaque
Carl Sagan