It is significant that we have reached a point in human history at which further attempts to make the world a better place will have to include not only changes to the world, but also changes to humanity, perhaps with the consequence that we, or our descendants, will cease to be human in the sense in which we now understand that idea. This possibility of a new phase of evolution in which Darwinian evolution, by natural selection, will be replaced by a deliberately chosen process of selection, the results of which, instead of having to wait the millions of years over which Darwinian evolutionary change has taken place, will be seen and felt almost immediately. This new process of evolutionary change will replace natural selection with deliberate selection, Darwinian evolution with “enhancement evolution.”
One of the ways in which philosophy can contribute to a better world is to help clear away the bad arguments that stand as much in the way of human progress and human happiness as do reactionary forces of a political and even of a military kind. When new technologies are announced, the first reaction is often either “wow—this is amazing!” or “yuck—this is sick!” This book is about the reasons and arguments that underlie both reactions, and about how it can sometimes be rational to move from “yuck!” to “wow!”