LECTURE I. 37 



fortification made of the most approved 

 rules of reasoning ; and neither this out- 

 work, nor the subject itself, has even been 

 assailed. Yet assertions have been made 

 which I am concerned to feel it an indis- 

 pensable duty publicly to answer in this 

 place. I shall include all the individuals 

 who compose this party, under a general 

 denomination, which I think appropriate to 

 them, and call them the Modern Sceptics. 



First then, I am instructed, that I ought to 

 consider life to be a property of certain struc- 

 tures, as gravitation and elasticity are said to 

 be properties of matter. With this injunc- 

 tion, however, I cannot comply, because I can 

 only think or consider in one way. I must 

 deduce rational inferences from the facts 

 belonging to any subject, or from analogies 

 existing between that subject and others 

 better understood. Now there is no ana- 

 logy between the permanent and inva- 

 riable properties of gravitation and elas- 

 ticity, and the occasional and variable pro- 

 perties of life. Therefore, if I judge from 

 analosv, I must think as I have hitherto 



D 3 



