To be a person, a being must be self-conscious, aware of its identity and its continued existence over time. - Derek Parfit

On all plausible theories, everyone’s well-being consists at least in part in being happy, and avoiding suffering.

When I consider the parts of the past of which I have some knowledge, I am inclined to believe that, in Utilitarian hedonistic terms, the past has been worth it, since the sum of happiness has been greater than the sum of suffering.

We live during the hinge of history. Given the scientific and technological discoveries of the last two centuries, the world has never changed as fast. We shall soon have even greater powers to transform, not only our surroundings, but ourselves and our successors. If we act wisely in the next few centuries, humanity will survive its most dangerous and decisive period. Our descendants could, if necessary, go elsewhere, spreading through this galaxy.