For many years, biology was largely descriptive (natural history), but with its emergence as a scientific discipline in its own right, a reductionist approach began, which has failed to be matched by adequate understanding of function of cells, organisms and species as whole entities. Every effort was made to explain biological phenomena in physico-chemical terms.It is argued that there is and always has been a clear distinction between life sciences and physical sciences, explicit in the use of the word biology. (...) If this distinction is real, it implies that biological phenomena can never be entirely satisfactorily explained in terms of extant physicochemical laws. One notable manifestation of this is that living organisms appear to -- actually do -- behave in purposeful ways, and the inanimate universe does not. While this fundamental difference continues to be suppressed, the purposiveness (or teleology) which pervades biology remains anathema to almost all scientists (including most biologists) even to the present day. We argue here that it can, however, become a perfectly tenable position when the Theory of Natural Selection is accepted as the main foundation, the essential tenet, of biology that distinguishes it from the realm of physical sciences. In accepting this position, it remains quite legitimate to expect that in many but not all circumstances, extant physical laws (and presumably others still to be discovered) are in no way breached by biological systems, which cannot be otherwise since all organisms are composed of physical material. (shrink)