Human enhancement is a phenomenon with an evolutionary history dating back to the beginnings of the universe, with its big bang, 13.7 billion years ago. Then, as cosmologists speaking empirically are fond of saying, human beings were stardust. Between then and now, much physical and mental enhancement has occurred. Imagine, for example, where Homo sapiens would be today if not for the evolving cognitive ability to invent language approximately 200,000 years ago. Language is a tool that enhances (makes greater and more effective, improves, augments, and advances) human beings' understanding and management of their physical and social environments. Humans create such tools as creatures whose brains are wired to desire degrees of completeness (perfection). Human beings are fated to deal with the question of enhancement.

Because ...