HUMAN NATURE A SUBJECT OF SCIENCE. 491 



culty inherent in the peculiar nature of those pheno- 

 mena) the science is still very imperfect ; arid were it 

 perfect, might probably be of little avail in practice, 

 since the data requisite for applying its principles to 

 particular instances would rarely be procurable. 



A case may be conceived, of an intermediate cha- 

 racter between the perfection of science, and this its 

 extreme imperfection. It may happen that the greater 

 causes, those on which the principal part of a pheno- 

 menon depends, are within the reach of observation 

 and measurement; so that if no other causes inter- 

 vened, a complete explanation could be given not only 

 of the phenomenon in general, but of all the varia- 

 tions and modifications which it admitted of. But 

 inasmuch as other, perhaps many other causes, sepa- 

 rately insignificant in their effects, co-operate or con- 

 flict in many or in all cases with those greater 

 causes; the effect, accordingly, presents more or less 

 of aberration from what would be produced by the 

 greater causes alone. Now, if these minor causes are 

 not so constantly accessible, or not accessible at all, 

 to accurate observation; the principal mass of the 

 effect may still, as before, be accounted for, and even 

 predicted; but there will be variations and modifica- 

 tions which we are not competent to explain tho- 

 roughly, and our predictions will not be fulfilled accu- 

 rately, but only approximately. 



It is thus, for example, with the theory of the 

 tides. No one doubts that Tidology (as Mr. Whewell 

 proposes to call it) is really a science. As much of 

 the phenomena as depends upon the attraction of the 

 sun and moon is completely understood, and may in 

 any, even unknown, part of the earth's surface, be 

 foretold with certainty; and the far greater part of 

 the phenomena depends upon those causes. But cir- 



