2 9 o POPULAR SCIENCE MONTHLY. 



Most books of the warfare-of-science sort are built more or less on 

 the same plan. Let us take the case of the figure of the earth for an 

 example. They often treat it in the following order: The primitive 

 conception, that of a flat earth; early scientific ideas of its sphericity; 

 opposition of the early church; evolution of a sacred theory drawn 

 from the Bible; its influence on christian thought; survival of the 

 idea of a spherical earth; contrast of the theological and scientific 

 spirit; last outbursts of theological hostility; retreat of the church; 

 final triumph of science over theology. Or, more briefly, their treat- 

 ment may often be summarized thus : Science always right ; theology 

 always interfering ; glory to us who have done away with superstition ! 



The real conflict of the ages has been between enlightenment and 

 ignorance. Sometimes the battle has been in the field of theology; 

 sometimes it has been in the field of science. The warfare has nearly 

 always been between religion and heresy; or between science and 

 pseudo-science; occasionally, but not very often, between religion and 

 pseudo (or it may sometimes be true) science. Usually, however, the 

 fields were plainly marked off. The theologians of any one epoch 

 treated theological questions and only those. They were not even in- 

 terested in scientific questions, as such. Men of science, before the 

 time of Galileo and Bruno, did not meddle with religion. Each class 

 kept to its own sphere. 



But let us return to the question of the figure of the earth. Untu- 

 tored man believed the earth to be flat; the sky to hang above it like 

 a canopy; the stars to be fixed to the canopy (or to hang from it as the 

 Arabs taught) ; the canopy to move from rising to setting, from east 

 to west. Now, this was an entirely scientific theory. It accounted 

 satisfactorily for every fact known to untutored man. A theory is 

 perfect when a future phenomenon can be predicted beforehand as 

 accurately as it can subsequently be observed. This was then, at the 

 time, a jDerfect theory; it needed no apologies. Aristarchus and other 

 Greeks saw that the observed phenomena (rising and setting of the 

 stars) could be as well explained by a spherical earth that turned on 

 its axis — as well, but no better. They did not know which theory was 

 true. They had no means of deciding the point. 



A matter of importance must be here alluded to. Long centuries 

 of experience have taught us that there is one and only one solution to 

 a scientific problem. We call such a unique solution a ' theory. ' Any- 

 thing less definite is a provisional 'hypothesis.' Now, the theories of 

 the ancients were generally held by them primarily as hypotheses. 

 Their whole attitude towards certainty was, in physical science, entirely 

 different from ours. It has required all the centuries to teach us our 

 lesson of implicit trust in scientific methods. Our trust is, in fact, in 

 methods, not, primarily, in results. In general, a physical theory attrib- 

 uted to one of the ancients was held by him as we hold a hypothesis. It 



