The fact that the names of biological species refer independently of identifying descriptions does not support the view of Ghiselin and Hull that species are individuals. Species may be regarded as natural kinds whose members share an essence which distinguishes them from the members of other species and accounts for the fact that they are reproductively isolated from the members of other species. Because evolutionary theory requires that species be spatiotemporally localized their names cannot occur in scientific laws. If natural (...) kind status is denied to species on this ground, it must also be denied to most classes of concrete entities which are now accorded such status. (shrink)

Some biologists and philosophers of biology have seen in Plato an especially objectionable version of essentialism or topology. Although kinds of animals are mentioned in almost all of Plato's dialogues, in none of them is there an explicity stated doctrine of animal kinds. An examination of the dialogues has, moreover, failed to reveal some implicit but consistent and unambiguous view of kinds that Plato might have held.

Our view of the first half of the 20th century has been influenced by what we suppose to have occurred in the middle of that century. It is by now part of the conventional wisdom of the geological community that during the 1950’s and 1960’s a revolution occurred. It is further supposed by many, that before the revolution there was among geologists an uneasiness resulting from the lack of an organizing principle in terms of which accumulating facts could be understood. (...) It is difficult to see our own times in the kind of perspective that historians consider so important an ingredient of ‘good’ history. Geologists now only in their middle years began their careers before the ‘new tectonics’ came to pervade their discipline. They do not look back upon prerevolutionary days as a time waiting to be saved from crisis nor do they see themselves as having collected facts in anticipation of being able to weave them into some pattern on the basis of some as yet undiscovered truth. (shrink)

It has been suggested that biological theories differ from physical theories because the subject matter of biology differs from the subject matter of physics especially in the fact that living bodies are more complex than nonliving bodies. It is shown that the interactional complexity of living bodies can only be expressed by invoking biological theories. The claim that living bodies are complex is, therefore, ultimately a claim about the nature of scientific theories rather than a claim about the nature of (...) the subject matter of biology resting upon a presystematic judgement. (shrink)