The received view that teleology has been successfully eliminated from the modern scientific worldview is challenged. It is argued that both the theory of natural selection and molecular biology presuppose the existence of natural teleology, and so cannot explain it. A number of other issues in the foundations of biology are briefly examined, while stress is laid throughout on empirical evidence of the rational agency inherent in life. It is urged that teleology be rehabilitated and that the reigning functionalist philosophy be replaced by a realistic view of biological functions as emergent properties of living matter within a broad, selforganization framework.