ABSTRACT
The man of science invents an hypothesis when ever he needs one in his business. It is to him merely a new tool, a n o v u m org a n u m . If there is not an ether it would be necessary to create one. So he did it. He had to have a noun for the verb “ undulate. ” When he had created it he saw it was not good. The properties with which he endowed it were self-contradictory, and it refused either to move with the earth or to pass through it. But these theoretical inconsistencies do not bother the physicist much. In spite of them the ether is a handy thing to have about the laboratory. The scientist does not abandon a theory because it has inconsistencies any more than he divorces his wife because she has in consistencies. Certainly the physicist did not consider himself presumptuous in thus inventing ether for his own convenience. He knew that the ordinary man had in the same way invented “ matter” long ago for his own convenience. It is a crude, inadequate and impossible idea, this naive conception of matter as something solid, heavy, hard, inert, indestructible, impenetrable, coloured and surfaced; but it is good enough for part of the people all of the time and for all of the people part of the
time. The physicist himself uses it for everyday. Only in his rigorous moments does he come down to bed-rock and say, with Poincare, “ Mass is a co efficient which it is convenient to introduce into calculations. ”
