SCIENCE 373 



This is another truth which carries with it its own 

 evidence and is incapable of proof. That such is the case 

 a little reflection will show. We act upon it constantly 

 in daily life without adverting to it. We know that if 

 we have spent all our money we can have none left 

 in our pockets, and we see plainly that any man who 

 really doubted whether, if he had lost one eye, he might 

 not at the same time still retain his original two eyes, or 

 who really doubted whether, if his legs were cut off, they 

 could not at the same time remain on, would have a 

 disordered mind. The simplest rustic knows that if his 

 wages have been paid to him, they are no longer owing, 

 and that if he has put his cart-horse in the stable, it is 

 no longer between the shafts. Yet the " law of contra- 

 diction " is but the summing-up, in an abstract formula, 

 of a multitude of particular instances of this kind, as to 

 each one of which no doubt is, or can be, for a moment 

 seriously entertained by any sane mind. If we were 

 really to doubt about the law of contradiction we should 

 fall into mere folly. For if anything can at the same 

 time both be and not be, then nothing can be true 

 without its being possible for it also to be untrue, and 

 this amounts to a paralysis of the intellect. 



But if we consider any distant period such as the 

 days of Julius Caesar or any distant spot, such as the 

 surface of the moon or even the star Sirius, we can see 

 clearly that the same law must necessarily also apply then 

 and there. Such a truth is therefore distinguished as an 

 absolute, necessary, and universal truth or principle 

 one applicable to all times and all places whatsoever. 



Another truth of a similar character, but less uni- 

 versal application, is an axiom we before * noted, namely, 



* See ante, p. 34. 



