22 THE PATH OF SCIENCE 



What is true of sculpture and architecture is true also 

 of literature. Literature takes different forms in different 

 periods. W^e may be inclined to value, for instance, the lyric 

 poetry of the recent era. But would we place it above the 

 epic poetry of the classical age or the religious poems of the 

 great period of high civilization which preceded the classical 

 age— from which we have such writing as the Book of Job or 

 Akhnaton's Hymn to the Sun? The science of the Renais- 

 sance, however, started where classical science ended, and 

 classical science was largely based on Egyptian and Baby- 

 lonian science. Through the ages, while the other activities 

 of man showed no definite progression but merely a growth 

 for a time and then a decline, the level of scientific knowl- 

 edge steadily increased. As Sarton says: * 



When one reads the history of science one has the ex- 

 hilarating feeling of climbing a big mountain. The history 

 of art gives one an altogether different iinpression. It is 

 not at all like the ascension of a mountain, always upward 

 whichever the direction of one's path; it is rather like a 

 leisurely journey across a hilly country. One cliinbs up to 

 the top of this hill or that, then down into another valley, 

 perhaps a deeper one than any other, then up the next hill, 

 and so forth and so on. An erratic succession of climaxes 

 and anticlimaxes the amplitude of which cannot be pre- 

 dicted. 



Let us consider, then, the progress of mankind as illus- 

 trated by the history of science or, as I should prefer to say, 

 the history of science and technology, the record of natural 

 knowledge and of invention. 



We may divide the history of mankind into gieat periods, 

 each of which is conditioned by a major invention; and it 

 is possible to carry out this division in many ways, accord- 

 ins: to the controllingr inventions that we select. The follow- 

 ins: classification seems to form a convenient framework for 

 our discussion: 



* Ibid., p. 11. 



