Teleonomy, a redefinition of purpose

In the previous chapter we discussed the release of behaviour patterns in terms of general control mechanisms without considering how and why such mechanisms might have evolved. In his preface to the 1965 edition of Darwin's book Lorenz cites as a key to modern behavioural biology ‘the fact … that behaviour patterns are just as conservatively and reliably characters of species as are the forms … of bodily structures; … (they) unite the members … of taxonomic units … (and) can become “vestigial” or “rudimentary” just as the latter can. Or on losing one function they may develop another.’

The idea of purpose has for many years been problematic in biology. However, it is possible to discuss some classes of purpose in biology from a scientific point of view – by referring to ‘purposes’ which specifically exclude the existence of any purposive entity as their source. One such alternative is ‘function’ as used by Lorenz.