POPULAR LECTURES, 29 



PASSAGES FROM POPULAR LECTURES. 



BY F. T. MOTT, F.R.G.S. 



No. 1.— THE MEANING OF " SCIENCE." 

 Let U3 consider what we understand, and what we ought to under- 

 stand, by the word " Science." The word itself is simply the Latin word 

 Scientia, stripped ot its Roman toga and put into an English di-ess. Its 

 original meaning is " knowledge," and the Romans used it in its widest 

 sense, as including all 7iianner of facts and propositions which were 

 known or supposed to be known. But in later times its meaning has 

 been restricted. The domains of art and of literature have been struck 

 out fi-om the domain of science. In our modern view science deals with 

 principles, art with practice. Science enquires about the laws of matter 

 and mind, art applies these laws in the production of results. To 

 ascertain the laws of animal life and of inherited qualities is science ; 

 to improve the breed of sheep and cattle by the application of this know- 

 ledge is art. But the domain of science is still veiy wide, and is fiirther 

 broken up by modern analysis into such sections as " pure science," 

 dealing with abstract ideas ; " physical science," investigating nature 

 mathematically; and "natural science," studying the laws of hfe. Yet 

 there is another analysis which requires to be made, and which seldom 

 is made by those who speak of science in a popular manner. Science, we 

 say, means " knowledge :" but what do we undex'stand by " knowledge?" 

 Under cover of this word are commonly confounded two very different 

 states of mind, and the confusion has led to many serious results. 



If we say that we knoic there is light in this room, and that we know 

 the light is produced by the gas, we are speaking of two quite different 

 kinds of knowledge, only one of which has any right in a strict sense to 

 be called knowledge at aU. The other is not knowledge but belief. 



We knoiu that there is light in this room ; but we do not know that 

 it is produced by bunaing gas ; we only believe that it is. 



Mark the difference. Knowledge is that of which the mind has 

 direct perception. Behef is that state which the mind arrives at from 

 the balancing of evidence. 



That there is light here is not a matter of inference, or judgment, or 

 opinion ; it is not a conviction ariived at from weighing evidence ; it is 

 the simple perception of a sensation. There can be no possibihty of 

 denjdng it. It is true knowledge. 



But to say that the light is produced by gas is to refer to a judgment 

 — not a dh'ect perception. We do not perceive the gas. It is far away 

 from us. We argue in our minds "what produces this light ? Is it the 

 sun ? Is it the moon ? Is it caudles ? Is it gas ? " We consider, and 

 balance the e\ddence, and conclude that the probabUity of its being gas 

 far outweighs all other suggestions. A con\'iction or behef is the result. 

 But this is not true knowledge, and it has nothing like the certainty of 

 true knowledge. 



We never can be sure that all possible evidence, upon any subject 

 whatever, has come before us ; nor that we have equally and impartially 

 weighed aU the evidence we had. How do we know, for instance, that 

 the gas-company are not trying an experiment to-night, and using some- 

 thing which is 7wt gas after aU ? We may have had the firmest belief 

 that the hght was produced by gas and yet find that we were wrong. 



Every belief is open to contradiction, and hable to change. As long 

 as a real belief exists at all it has the same force with us as if it were 



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