8 LESSONS FKOM NATUBE. [CHAP. I. 



considerations in order to maintain three propositions, assent 

 on condition to which must be a sine qua non to farther dis- 

 thm^pre-&quot; 5 cussion, as without such assent discussion would be 



liminarypro- ... ,, . 



positions. an aimless and iutile waste ot time. 



The first of these considerations relates to &quot; absolute scepti 

 cism ;&quot; and the first proposition is that such scepticism, with 

 every position which necessarily involves it, is to be regarded 

 as an absurdity. The second consideration relates to good 

 faith and economy of time in controversy ; and the second 

 proposition is that no position is to be defended which cannot 

 be believed to be really and seriously maintained by some 

 one. The third consideration refers to language ; and the 

 third proposition is that what is distinctly and clearly con 

 ceived by the mind can be expressed by terms practically 

 adequate to convey such conceptions to other minds. 



The first preliminary consideration to be insisted on may 

 be stated thus : 



I. Absolute scepticism, with every position that necessarily 

 involves it, is to l)e rejected as an absurdity. 



The truth contained in this assertion serves to clear away 

 The first pro- a liinderance which otherwise might at first, and 

 indeed continually, impede our progress. This 

 hinderance consists in a haziness as to the necessary limits 

 of all discussion, hiding the point at which all controversy 

 becomes unmeaning nay, logically impossible. Before dis 

 cussing any fundamental questions, the truth that discussion 

 is, as a fact, possible should be clearly recognised, as also 

 that there is such a thing as truth, and that some conclusions 

 are true. Without this recognition, whatever conclusions 

 we arrive at may be vitiated by a latent doubt whether any 

 conclusion on any subject can under any circumstances be 

 ever valid. If nothing is certain, if there is no real dis 

 tinction between truth and falsehood, there can, of course, be 

 no useful discussion. If any man is not certain, absolutely 

 certain, that he is not a tree or the rustle of its leaves ; if he 

 is not certain that there are such things as thoughts and 



