Now I can rejoice that I knew you, rather than mourn because I lost you.

All human plans [are] subject to ruthless revision by Nature, or Fate, or whatever one preferred to call the powers behind the Universe.

There were other thinkers, Bowman also found, who held even more exotic views. They did not believe that really advanced beings would possess organic bodies at all. Sooner or later, as their scientific knowledge progressed, they would get rid of the fragile, disease-and-accident-prone homes that Nature had given them, and which doomed them to inevitable death. They would replace their natural bodies as they wore out — or perhaps even before that — by constructions of metal and plastic, and would thus achieve immortality.