30 PHYSICAL SCIENCE 



Natural Science has occurred since men learned 

 to concentrate their immediate attention on the 

 question of how phenomena are related, and to 

 cease, for the time at any rate, to ask why they 

 appear. Before Galileo's day men sought to 

 explain the fall of bodies to the earth by saying 

 that "every body sought its natural place" — 

 the place of heavy bodies being below, and that 

 of light ones above. Galileo, exercising the 

 true scientific spirit of restraint, set himself to 

 determine by experiment hozi) bodies fell. He 

 thus discovered that the speed was proportional 

 to the time of fall, and, by dropping bodies from 

 the leaning tower of Pisa, showed that, contrary 

 to the received doctrine of tendency to seek 

 their natural place, heavy bodies fell no faster 

 than light ones. 



The natural laws of falling bodies were thus 

 established, and the method of their discovery 

 shows how such steps in knowledge are always 

 made. In the first stage new phenomena are 

 observed, or old phenomena are brought under 

 accurate and quantitative measurement, probably 

 by the light of tentative hypotheses. - Here the 

 virtues of patience, accuracy, incredulity, and 

 conscientious elimination of personal bias are of 

 chief account. The classical example is Kepler's 

 life-study of the motions of the planets — a study 

 which led to the establishment of general laws, 

 such as that the planets move in ellipses having 

 the sun in one focus. 



But such laws alone are insufficient to satisfy 

 our minds, which inevitably return to the question 

 why such relations hold. The relations are mis- 

 interpreted and re-interpreted, until some Newton 



