The ultimate source of explanation in biology is the principle of natural selection. Natural selection means differential reproduction of genes and gene combinations. It is a mechanistic process which accounts for the existence in living organisms of end-directed structures and processes. It is argued that teleological explanations in biology are not only acceptable but indeed indispensable. There are at least three categories of biological phenomena where teleological explanations are appropriate.

More than once in his writings, Hobbes pronounced on the scope and organization of science. He had provocative views about the subjects that could be termed “scientific” about the scientific subjects that were basic, and about the relative benefits of the various sciences. Some of these views reflect his allegiance to the new mechanical philosophy and his opposition to Aristotelianism; others show the influence of Bacon, who was a virtuoso deviser of blueprints for science. Still others belong to a program (...) of self-advertisement: Hobbes wished to be seen as an important scientist himself - an important worker in the field of optics and no less than the inventor of the science of politics. After expounding Hobbes's views about the organization of science and considering some of the problems they raise, I shall suggest that they throw light on old questions about what has been called “Hobbes's system”. (shrink)