136 ON THE METHOD OF ZADIG. [LECT. 



who wrote a given document was actuated by other 

 than ordinary human motives, such documents are of 

 no more evidential value than so many arabesques. 



Archaeology, which takes up the thread of history 

 beyond the point at which documentary evidence fails 

 us, could have no existence, except for our well- 

 grounded confidence that monuments and works of 

 art or artifice, have never been produced by causes 

 different in kind from those to which they now owe 

 their origin. And geology, which traces back the 

 course of history beyond the limits of archaeology, 

 could tell us nothing except for the assumption that, 

 millions of years ago, water, heat, gravitation, friction, 

 animal and vegetable life, caused effects of the same 

 kind as they do now. Nay, even physical astronomy, 

 in so far as it takes us back to the uttermost point of 

 time which palaetiological science can reach, is founded 

 upon the same assumption. If the law of gravitation 

 ever failed to be true, even to the smallest extent, for 

 that period, the calculations of the astronomer have 

 no application. 



The power of prediction, of prospective prophecy, is 

 that which is commonly regarded as the great preroga- 

 tive of physical science. And truly it is a wonderful 

 fact that one can go into a shop and buy for small 

 price a book, the "Nautical Almanac/' which will 

 foretell the exact position to be occupied by one of 

 Jupiter's moons six months hence; nay more, that, 

 if it were worth while, the Astronomer Koyal could 

 furnish us with as infallible a prediction applicable 

 to 1980 or 2980. 



