The Relation Between the Movements of the Eyes and the Movements of the Head¹

Abstract

We all know that it was a long time before mankind found out that the earth moves. For ages the apparent motion of the heavenly bodies was supposed to be their real motion, the earth being fixed. We, who know something of the truth in this matter, do not, however, any more than our ancestors did, see or feel the earth move. We believe that it does so either because we have been told by some one who, we think, knows about such things, or because we have reasoned the matter our from data observed by ourselves or reported by credible observers. But in habitual thought and speech we go back to the old assumption which, for our practical, terrestrial purposes, answers well enough, and is perfectly in accordance with our sensations.