A CRITICISM. 9 



Conrad Gessner and other early zoologists began by classifying animals 

 according to the number of their horns! Political Economy begins by 

 classifying social action under a law of Supply and Demand. When peo- 

 ple believed that the earth was flat they generalised the facts connected 

 with the fall of heavy bodies into a conception of " up and down." These 

 were two opposite directions in space. Heavy bodies took the ' ' down- 

 ward;" it was their nature. But in time, and as fresh facts came in, it be- 

 came impossible to group animals any longer by their horns; " up and 

 down" ceased to have a meaning when it was known that the earth was 

 round. Then fresh laws and statements had to be formed. In the last- 

 mentioned case it being conceived that the earth was the centre of the 

 universe the new law supposed was that all heavy bodies tended to the 

 centre of the earth as such. This was all right and satisfactory for a while; 

 but presently it appeared that the earth was not the centre of the universe, 

 and that some heavy bodies such as the satellites of Jupiter did not in 

 fact tend to the centre of the earth at all. Another lump of ignorance 

 (which had enabled the old generalisation to exist) was removed, and a 

 new generalisation, that of universal gravitation, was after a time formed. 

 But it is probable that this law is only conceived of as true thro' our ig- 

 norance; nay it is certain that belief in its truth presents the gravest diffi- 

 culties. 



lu fact here we come upon an important point. It is sometimes said 

 that, granting the above arguments and the partiality and defectiveness of 

 the laws of Science, still they are approximations to the truth, and as each 

 fresh fact is introduced the consequent modification of the old law brings 

 us nearer and nearer to a limit of rigorous exactness which we shall reach 

 at last if we only have patience enough. But is this so? What kind of 

 rigorous statement shall we reach when we have got all the facts in? Re- 

 membering that Nature is one, and that if we try to get a rigorous state- 

 ment for one set of phenomena (as say the lunar theory) by isolating them 

 from the rest, we are thereby condemning ourselves beforehand to a false 

 conclusion, is it not evident that our limit is at all times infinitely far off? 

 If one knew all the facts relating to a given inquiry except two or three, 

 one might reasonably suppose that one was near a limit of exactness in 

 one's knowledge; but seeing that in our investigation of Nature we only 

 know two or three, so to speak, out of a million, it is obvious that at any 

 moment the fresh law arising from increased experience may completely 

 upset our former calculations. There is a difference between approximat- 

 ing to a wall and approximating to the North Star. In the one case you 

 are tending to a speedy conclusion of your labors, in the other case you 

 are only going in a certain direction. The theories of Science generally be- 

 long under the second head. They mark the direction which the human 

 mind is taking at the moment in question, but they mark no limits. At 

 each point the appearance of a limit is introduced which becomes, like 

 a mirage in the desert, an object of keen pursuit; but the limit is not really 



