WEST OXFORD SOCIETY. 73 



ments, or making' observations to discover the truth, A theory is 

 a complete system of suppositions put together for the purpose of 

 explaining all the facts that belong to some one science. In geom- 

 etry for example, hypothesis may aid in the construction of the 

 correct theory the confirmation of which must depend upon demon- 

 stration ; but let it be remembered that the inability to construct 

 the demonstration does not disprove the correctness of the theory. 

 Dr. Franklin in studying the laws and nature of electricity, started 

 with the inquiry, " Is not the electrical spark identical with the 

 flashes of lightning?" This was his hypothesis, or guess, or sup- 

 position, which by repeated experiments he succeeded in proving 

 to be true. Hypothesis when demonstrated ceases to be hypothe- 

 sis by becoming theory ; for when the principles employed in the 

 explanation of the phenomena are known to exist, you have the 

 difference between theory and hypothesis, the latter being but sup- 

 position. Or in other words, hypothesis differs from theory in this : 

 the former is the supposing of something, the existence of which 

 is not proved, to explain phenomena which have been observed ; 

 the latter explains phenomena by causes which are known to exist 

 and to be in operation. 



Hypothesis, then, is no more to be rejected as useless than theo- 

 ry ; for the right use of the former aids in discovering the latter. 

 The suppositions of which an hypothesis is constructed are not 

 arbitrary fictions, altogether, but suppositions conformable to care- 

 ful observation, experience or analogy. 



Practical art, or knowledge, is generally understood to be such 

 as has been derived from experience. Among the Greek physicians, 

 those who founded their practice on experience called themselves 

 empirics ; those who relied on theory, methodists ; and those who 

 held to the middle course, dogmatists. The term empiricism be- 

 came naturalized in England when the writings of Galen and other 

 opponents of the empirics were in repute, and hence it was applied 

 generally to pretenders to knowledge. It properly relates to 

 knowledge that is the result of experience. The term is used in 

 the writings of Aristotle in the sense as historical. Historical 

 knowledge is the knowledge that a thing is or was. Empiricism, 

 then, is an unreasoning and instructive imitation of previous prac- 

 tice. It allows nothing to be true nor certain but what is given 

 by experience, and, therefore, rejects all knowledge a prio7^i. Locke 

 in tracing all knowledge to experience, gives his testimony in favor 

 of empiricism. 



