Some Problems about Rationality

In what follows I shall discuss a philosophical problem arising out of the practice of anthropologists and sociologists which may be stated, in a general and unanalysed form, as follows: when I come across a set of beliefs which appear prima facie irrational, what should be my attitude towards them? Should I adopt a critical attitude, taking it as a fact about the beliefs that they are irrational, and seek to explain how they came to be held, how they manage to survive unprofaned by rational criticism, what their consequences are, etc? Or should I treat such beliefs charitably: should I begin from the assumption that what appears to me to be irrational may be interpreted as rational when fully understood in its context? More briefly, the problem comes down to whether or not there are alternative standards of rationality.