REASONING. 343 



numerous points involved in a stove's not smoking the one 

 special point of smoke pouring freely out of tlie stove-pipe's 

 mouth, he would, probably, owing to the few associations 

 of that idea, have been immediately reminded of the law 

 that a fluid passes more rapidly out of a pipe's mouth if 

 another fluid be at the same time streaming over that 

 mouth ; and then the rapid draught of air over the stove- 

 pipe's mouth, which is one of the points involved in the 

 car's motion, would immediately have occurred to him. 



Thus a couple of extracted characters, with a couple of 

 their few and obvious connections, would have formed the 

 reasoned link in the passenger's mind between the phenom- 

 ena, smoke stopping and car moving, which were only linked 

 as wholes in the brakeman's mind. Such examples may seem 

 trivial, but they contain the essence of the most refined and 

 transcendental theorizing. The reason why physics grows 

 more deductive the more the fundamental properties it as- 

 sumes are of a mathematical sort, such as molecular mass 

 or wave-length, is that the immediate consequences of these 

 notions are so few that we can survey them all at once, and 

 promptly pick out those which concern us. 



Sagacity ; or the Perception of the Essence. 



To reason, then, we must be able to extract characters, — 

 not any characters, but the right characters for our conclu- 

 sion. If we extract the wrong character, it wdll not lead to 

 i hat conclusion. Here, then, is the difficulty : Hoiv are 

 characters extracted, and lohy does it require the advent of a 

 ^'enius in many cases before the fitting character is brought to 

 Ught ? Why cannot anybody reason as well as anybody 

 slse ? "Why does it need a Newton to notice tlie law of the 

 squares, a Darwin to notice the survival of the fittest '? To 

 answer these questions we must begin a new research, and 

 see how our insight into facts naturally" grows. 



All our knowledge at first is vague. When w^e say that 

 a thing is vague, we mean that it has no subdivisions ab in- 

 tra, nor precise limitations ab extra ; but still all the forms 

 of thought may apply to it. It may have unity, reality, ex- 

 ternality, extent, and what not — thinghood, in a word, but 



