ETHOLOGY. 597 



succession or of co-existence, which holds true in all instances within our 

 limits of observation, but is not of a nature to afford any assurance that it 

 would hold beyond those limits ; either because the consequent is not really 

 the effect of the antecedent, but forms part along with it of a chain of ef- 

 fects flowing from prior causes not yet ascertained, or because there is 

 ground to beheve that the sequence (though a case of causation) is resolv- 

 able into simpler sequences, and, depending therefore on a concurrence of 

 several natural agencies, is exposed to an unknown multitude of possibilities 

 of counteraction. In other words, an empirical law is a generalization, of 

 which, not content with finding it true, we are obliged to ask, why is it 

 true? knowing that its truth is not absolute, but dependent on some more 

 general conditions, and that it can only be relied on in so far as there is 

 ground of assurance that those conditions are realized. 



Now, the observations concerning human affairs collected from common 

 experience are precisely of this nature. Even if they were universally and 

 exactly true within the bounds of experience, which they never are, still 

 they are not the ultimate laws of human action ; they are not the principles 

 of human nature, but results of those principles under the circumstances in 

 which mankind have happened to be placed. When the Psalmist " said in 

 his haste that all men are liars," he enunciated what in some ages and coun- 

 tries is borne out by ample experience ; but it is not a law of man's nature 

 to lie ; though it is one of the consequences of the laws of human nature, 

 that lying is nearly universal when certain external circumstances exist uni- 

 versally, especially circumstances productive of habitual distrust and fear. 

 When the character of the old is asserted to be cautious, and of the young 

 impetuous, this, again, is but an empirical law ; for it is not because of their 

 youth that the young are impetuous, nor because of their age that the old 

 are cautious. It is chiefly, if not wholly, because the old, during their 

 many years of life, have generally had much experience of its various evils, 

 and having suffered or seen others suffer much from incautious exposure 

 to them, have acquired associations favorable to circumspection ; while the 

 young, as Avell from the absence of similar experience as from the greater 

 strength of the inclinations which urge them to enterprise, engage them- 

 selves in it more readily. Here, then, is the explanation of the empirical 

 law ; here are the conditions Avhich ultimately determine whether the law 

 holds good or not. If an old man has not been oftener than most young 

 men in contact with danger and difiiculty, he will be equally incautious ; if 

 a youth has not stronger inclinations than an old man, he probably will be 

 as little enterprising. The empirical law derives whatever truth it has 

 fi-om the causal laws of which it is a consequence. If we know those laws, 

 we know what are the limits to the derivative laAv ; while, if we have not 

 yet accounted for the empirical law — if it rests only on observation — there 

 is no safety in applying it far beyond the limits of time, place, and circum- 

 stance in which the observations were made. 



The really scientific truths, then, are not these empirical laws, but the 

 causal laws which explain them. The empirical laws of those phenomena 

 which dejDend on known causes, and of which a general theory can there- 

 fore be constructed, have, whatever may be their value in practice, no other 

 function in science than that of verifying the conclusions of theory. Still 

 more must this be the case when most of the empirical laws amount, even 

 within the limits of observation, only to ajoproxirnate generalizations. 



§ 2. This, however, is not, so much as is sometimes supposed, a peculiarity 



