ABSTRACT
Why do rituals play such an important part in many religious systems? That question is central to the following three chapters. But ‘Why’ questions about behaviour can be answered in a number of ways. Biologists classify these into four categories, which can best be presented by an example. Suppose you were asked ‘Why does your thumb move in a different way from the other fingers?’ You might give an answer in terms of the differences
in skeletal structure and muscle attachments between the thumb and the other fingers – an answer referring to the immediate causation of thumb movement. You might give a developmental answer, describing how, as the finger rudiments developed, one came to have a different structure from the others. As a third possibility, you might say that an opposable thumb makes it easier to pick things up, or to climb trees – a functional answer. Finally, you might give an evolutionary answer, saying that we are descended from monkey-like creatures who had opposable thumbs. Biologists interested in behaviour have found that these four questions – immediate causation, development, function, and evolution – though independent and logically distinct, are often inter-fertile (Tinbergen, 1963).
