Page:Philosophy and Fun of Algebra.djvu/57

THE USE OF SEWING CARDS whoever stepped on it wherever he or she wished to go—which is a quite different thing. The true Boole method depends essentially on making a right use of imaginary hypotheses. The magic carpet depends for its efficacy on making a wrong use of imaginary hypotheses.

People get to very queer places on that carpet. I have been for several excursions on it, so I know.

One of the places it can take you to is a town where all the front doors open on to a street very like Regent Street; with the most gorgeous millinery, jewellery, and fruits in shop windows; and all the back doors open to wild country where blue roses, black tulips, and the fattest double carnations of all colours (including green ones) grow wild in the hedges and fields; and where all the pigs have wings.

Another place that it can take you to is one where pigs can wallow in all the filth they like without soiling their wings; and moths fly into candles without singling theirs.

The carpet will take you straight to whatever 53