In recent years, the views of the German philosopher Peter Sloterdijk about humanism and the biological self-engineering of mankind caused much turmoil in European intellectual circles. However, this is just one episode in a more general current controversy about the ethics of self-manipulation, a debate that often centers around the recent progress in genomics and the possibility of shaping human genetic structure. The complete sequencing of the human genome has reinforced this focus. Making the human genome the object of a highly visible world-wide research effort has reinforced popular notions stressing the centrality of the genome in defining individuality and humanity. As a result, proponents and opponents of the self-engineering of human nature have often concentrated on technologies related to the genome. However, if one compares "genome-based" and "brain-based" explanations of Self and behavior, it turns out that neural aspects of human nature are more directly relevant. Many philosophical and ethical questions traditionally raised about genetics and genomics acquire more relevance and urgency when re-examined in the context of neuroscience.