XI PHENOMENA OF ORGANIC NATURE 373 



would consider those facts a very good experimental 

 verification of your hypothesis, touching the cause 

 of the abnormal phenomena observed in your 

 parlour, and would act accordingly. 



Now, in this suppositious case, I have taken 

 phenomena of a very common kind, in order that 

 you might see what are the different steps in an 

 ordinary process of reasoning, if you will only take 

 the trouble to analyse it carefully. All the opera- 

 tions I have described, you will see, are involved 

 in the mind of any man of sense in leading him 

 to a conclusion as to the course he should take in 

 order to make good a robbery and punish the 

 offender. I say that you are led, in that case, to 

 your conclusion by exactly the same train of 

 reasoning as that which a man of science pursues 

 when he is endeavouring to discover the origin and 

 laws of the most occult phenomena. The process 

 is, and always must be, the same ; and precisely 

 the same mode of reasoning was employed by 

 Newton and Laplace in their endeavours to dis- 

 cover and define the causes of the movements of 

 the heavenly bodies, as you, with your own common 

 sense, would employ to detect a burglar. The 

 only difference is, that the nature of the inquiry 

 being more abstruse, every step has to be most 

 carefully watched, so that there may not be a 

 single crack or flaw in your hypothesis. A 

 flaw or crack in many of the hypotheses of 



