102 J. HOPKINSON — ANNIVEESAET ADDRESS : 



vertically, "we miglit come to the same conclusion, for we should 

 find that the higher we were, the further would the horizon recede. 

 This inference could not he formed without some knowledge of 

 geometry, or at least without bringing our reasoning powers into 

 use. It would therefore be a scientific inference, and we should 

 find it much more difficult to convince others of the correctness of 

 our conclusion than we should have done if we had travelled round 

 the earth in diiierent directions, measuring our course, and so had 

 perceived that its form was globular or nearly so. But we should 

 only have attained a knowledge of the thing, — the knowledge that 

 the earth is a sphere or spheroid. To complete our investigation 

 we must arrive at a knowledge of the cause of its sphericity, and 

 of the reason why it is not perfectly spherical, which can only be 

 done by exercising our reasoning and imaginative faculties, and in 

 such ways we build up science. 



As the cause of any natural phenomenon can very seldom be 

 directly perceived, our first attempt to ascertain it, after having 

 fully investigated, by observation or experiment, all the facts 

 connected with it, is usually by forming an hypothesis ; and if our 

 hypothesis accounts for most of the facts, and does not appear to 

 be at variance with any, it becomes a theory ; if no other explana- 

 tion seems to be possible, it may become a scientific doctrine. 



To discover a law, the exercise of our reasoning and imaginative 

 faculties is still more imperative, for we can never perceive a law 

 of nature. We may, however, as in the case of gravitation, discover 

 a law without knowing the cause. 



That the earth is a globe was inferred by astronomers long before 

 it was circumnavigated. This was therefore a scientific inference. 

 It gave rise to the first recorded battle between reason and 

 prejudice, being opposed and derided on Scriptural grounds, and so 

 dogmatically that most of the Fathers of the Church denied the 

 possibility of salvation to those who believed it, and thought that 

 the earth might be inhabited on opposite sides. 



The theory of Copernicus that the earth and planets revolve 

 around the sim, was ridiculed on the same grounds. It was a 

 scientific conception opposed to the direct evidence of our senses, 

 and to the literal intei-pretation of certain passages in Scripture. 

 Copernicus died on the very day that his great work on the 

 ' Revolution of the Heavenly Bodies ' was published, and so 

 escaped persecution. The same theory was afterwards proclaimed 

 by Giordano Bruno, before the world was prepared to receive it, 

 and for this and other heresies he was imprisoned for six years and 

 then burned alive. The belief that the great astronomical truths 



