Page:Stabilizing the dollar, Fisher, 1920.djvu/98

44 or like the illusion that the sun rises and sets instead of the earth revolving.

Thus we have been deceived by appearances in commerce just as we have been deceived by appearances in astronomy. The earth seems to be fixed and all the other heavenly bodies seem to move. It is true, of course, that these bodies do move; yet most of the motion which we are tempted to attribute to them is not theirs but the earth's. So money seems to be fixed and all the other commodities seem to move. And it is true that these commodities do move; yet most of the motion we are tempted to attribute to them is not of them but of money.

It took a long time to overcome the apparent evidence of our senses in regard to the actual rising and setting of the sun, moon, and stars. In fact, the first astronomers did not doubt this popular view but accepted it and succeeded, by numerous special and complicated assumptions (of "cycles" and "epicycles"), in explaining all observed movements, even those of the planets. This was the system of Ptolemy; and one of the greatest revolutions in human thought was the adoption of the later astronomical system of Copernicus. This revolution of thought in astronomy was based chiefly on the presumption that a simple explanation is more likely to be correct than a complicated one.

Sooner or later a similar revolution will be wrought in popular economics and we shall come to see that the course of prices is due chiefly to the movement of money and not to coincident movements of all or almost all other commodities at once. We now think only of the gold-value of goods; we shall then think also of the goods-value of gold.