To find the spirit of philosophy still residing in the imaginations of empirical ""hard"" scientists in this age of anxiety and ideological aridity is a comfort. Pulitzer Prize-winning (So Human an Animal, 1968) microbiologist Dubos' inquiry into the nature of Homo sapiens sapiens ranges from biological to social and cultural to moral and spiritual definitions of ""humanness."" His historical continuum recalls a lost Paradise, places us in the technological quandary (with attention to the ""limits of growth"") but foresees a New Jerusalem -- a world federation based on a higher unity of man's diversities. Dubos refutes pessimists like Toffler, as well as Colin Turnbull's controversial assertion that natural man, exemplified by the Iks of northern Uganda, is born bad. The emphasis is on free will and moral judgment -- the solution to the struggle between good and evil is choice. A benign futurology composed of equal parts of reason and faith, definitely on the side of the angels.