From the perspective of biology, knowledge—that is, the cognitive relationship between two terms—is a form of self-reference. There is the world; and there is the world in a pattern shaped by the world itself, and that pattern refers cognitively to the world. The knower is part of the known and has been shaped by what is known. The reflector reflects, more or less adequately, because it is itself part of what is being reflected. The biological perspective, therefore, provides an assurance that the reflector is adequate and also explains, at the same time, how it has been shaped by natural selection, to be adequate. As Carl Sagan once remarked, ‘humans are the stuff of the cosmos examining itself.
There has always been enormous doubt in this area. One of the central problems of philosophy has been to determine how adequate the reflector or knower or mirror can be thought to be. Historians of philosophy are all agreed that the problem stems from Descartes’s concentration of a knowing subject which faces an objective world. By thus formulating the knowing relationship as if the knower were some alien from outer space or a person supposedly occupying an Olympian stance, Descartes made it well-nigh impossible to account for the adequacy of the knower, the reflector or the mirror. Whether the problem originated with Descartes or not, without biology it remains a very formidable problem. For wherever one thinks the knower is taking up his position, he or she has no intimate relation to what is known, and whatever he or she is asserting cannot be considered to be adequate to the world as long as one cannot show that the knower or the mirror itself has its origin and place inside that world and is part of it and that the relationship of knower to known is a relation of self-reference.
There are good reasons why the question of adequacy should be in the centre. Whatever is paraded as knowledge must claim, among other things, that it is equipped to refer to the world. There must be indications as to how it is to be tested, what theories are to be given preference, what kind of coherence with other knowledge is to be expected and what theories are to