None of this seemed particularly ambitious, however, compared with the claim soon to follow. In the back of the audience, carefully reviewing his notes, sat Randal Koene, a bespectacled neuroscientist wearing black cargo pants, a black T-shirt showing a brain on a laptop screen, and a pair of black, shiny boots. Koene had come to explain to the assembled crowd how to live forever. ''As a species, we really only inhabit a small sliver of time and space,''Koene said when he took the stage. ''We want a species that can be effective and influential and creative in a much larger sphere.''