Swans, white and black, have a long history in scholastic and then mathematical logic, figuring too frequently in illustrations of modus ponens:
All swans are white. A is a swan. Ergo, A is white. The heavy, unquestioning use of this scheme presumably reflects the fact that northern hemisphere swans, European and Japanese swans in particular, were/are white. All this changed when the southern hemisphere, Australian and New Zealand, black swan, Cygnus atratus, was discovered in the late 18th century. "Black swan" then came to have another, quite different connotation. It is used to describe putatively rare things when they are in fact found and sometimes even to derogate rareness, as in the recent heavy use of variants of Unscrupulous, greedy bankers are not black swans. Produce is used in logic as shorthand for provide an instance of in the sense of the existential quantifier, assert or show there is at least one S such that S is an x. Obtusely, I had not thought about the 'production of a black swan' in its other, literal or Marxist economic sense, accomplished say by painting a white swan black; but I agree that the idea is repellent. (We again have a significant, growing population of white swan pairs resident throughout the year in our glacial ponds/reservoirs here in Massachusetts west of Boston. They are very tolerant of people, and I should not want to see that change.) John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
