ABSTRACT
Pi has had a very long life in the geometry of circles, even though it was first proposed as the name for this particular ratio only in 1706, by the Welsh mathematician William Jones, probably because it is the first letter of the Greek words perimetros (perimeter) and periphereia (periphery). The endless attempt to express it completely is like a quest to discover the incomparable glassy essence of incommensurability itself. The life of Pi serves to remind people that as valuing beings, as moral beings, even as a civilisation, people live with incommensurability: indeed, that we are constituted in it. Incommensurability is a concept with a notable recent history in the philosophy of science. The need for value is a need for value conflict, especially of the more irresolvable kind. Another kind of danger lies in zealous commensuration, the search for some founding value to explain all the others, until they all disappear.
