All cultural endeavours require rituals. There could be no modern science without the rituals of the lab and academy, say. There could be no modern art if people did not understand the rituals of the gallery, and how to make the right gestures to break them. And, of course, human community and religious practice is unimaginable without rituals, from shaking hands to lighting candles.

So what is a ritual? Well, there are many answers to this question. But I'd like to focus on one that highlights the link between rituals and the transcendent. The psychologist, Abraham Maslow, called it B-cognition, as opposed to D-cognition.

D-cognition is to do with the humdrum. The D stands for "deficiency" and Maslow saw this cognition as the kind of knowledge required for the daily business of striving and surviving, which is largely a process of finding what we lack. Hence, deficiency.