86 SCIENTIFIC INVESTIGATION 



sort of special apprenticeship to the craft. To hear all 

 these large words, you would think that the mind of a 

 man of science must be constituted differently from that 

 of his fellow men ; but if you will not be frightened by 

 terms, you will discover that you are quite wrong, and 

 that all these terrible apparatus are being used by your- 

 selves every day and every hour of your lives. 



There is a well-known incident in one of Moliere's 

 plays, where the author makes the hero express un- 

 bounded delight on being told that he had been talking 

 prose during the whole of his life. In the same way, I 

 trust, that you will take comfort, and be delighted with 

 yourselves, on the discovery that you have been acting 

 on the principles of inductive and deductive philosophy 

 during the same period. Probably there is not one here 

 who has not in the course of the day had occasion to set 

 in motion a complex train of reasoning, of the very 

 same kind, though differing of course in degree, as that 

 which a scientific man goes through in tracing the 

 causes of natural phenomena. 



A very trivial circumstance will serve to exemplify 

 this. Suppose you go into a fruiterer's shop, wanting 

 an apple, you take up one, and, on biting it, you 

 find it is sour; you look at it, and see that it is hard and 

 green. You take up another one, and that too is hard, 

 green, and sour. The shopman offers you a third; but, 

 before biting it, you examine it, and find that it is hard 

 and green, and you immediately say that you will not 

 have it, as it must be sour, like those that you have 

 already tried. 



Nothing can be more simple than that, you think; 

 but if you will take the trouble to analyse and trace out 

 into its logical elements what has been done by the 

 mind, you will be greatly surprised. In the first place 



