io MODERN SCIENCE : 



there it is only an effect of the standpoint, and disappears again after 

 a time as the observer moves. In the case of gravitation there is for the 

 moment an appearance of finality in the law of the inverse square of the 

 distance, but this arises probably from the fact that the law is derived 

 from a limited area of observation only, namely the movements (at great 

 distances from each other) of some of the heavenly bodies. l The Caven- 

 dish and Schehallien experiments do not show more than that the law at 

 ordinary distances on the earth's surface does not vary very much from 

 the above; while the so-called molecular forces compel us (unless we 

 make the very artificial assumption that a variety of attractions and re- 

 pulsions coexist in matter alongside of, and yet totally distinct from, the 

 attraction of gravitation) to suppose very great modifications of the law 

 for small distances. In fact, as we saw of Boyle's law before the New- 

 tonian law is probably metaphysical true under certain limited condi- 

 tions and the appearance of finality has been given to it by the fact that 

 our observations have been made under such or similar conditions. 

 When we extend our observations into quite other regions of space, the 

 law of the inverse square ceases to appear as even an approximation to the 

 truth as, for instance, the law of the inverse fifth power has been thought 

 to be nearer the mark for smaller molecular distances. 



And indeed the state of the great theories of Science in the present 

 day the confusion in which the Atomic theory of physics finds itself, the 

 dismal insufficiency of the Darwin theory of the survival of the fittest ; 

 the collapse in late limes of one of the fundamental theories of Astronomy, 

 namely that of the stability of the lunar and planetary orbits ; the cata- 

 clysms and convulsions which Geology seems just now to be undergoing ; 

 the appalling and indeed insurmountable difficulties which attach to the 

 Undulatory theory of Light ; the final wreck and abandonment of the 

 Value-theory, the foundation-theory of political Economy all these things 

 do not seem to point to very near limits of rigorous exactness ! An im- 

 pregnable theory, or one nearing the limit of impregnability, is in fact as 

 great an absurdity as an impregnable armor-plate. Certainly, given the 

 cannon-balls, you can generally find an armor-plate which will be proof 

 against them ; but given the armor-plate, you can always find cannon- 

 balls which will smash it up. 



The method of Science, as being a metho'd of artificial limitation or 

 actual ignorance, is curiously illustrated by a consideration of its various 



' It is not generally realised how feeble a force gravitation is. It is calculated (Encycl. 

 Brit., Art. Gravitation) that two masses, each weighing 415,000 tons, and placed a mile 

 apart, would exert on each other an attractive force of only one pound. If one, therefore, 

 was as far from the other as the moon is from the earth, their attraction would only 

 amount to - T of a pound. This is a small force to govern the movement of a 



57,6oo,ooo,oooth 



body weighing 415,000 tons! and it is easy to see that a slight variation in the law of 

 the force might for a long period pass undetected, though in the course of hundreds of 

 xenturies it might become of the greatest importance. 



