48 SCIENCE IN GRECO-ROMAN ANTIQUITY 



of atoms resulting therefrom, it simply adopted the 

 cosmological ideas of the first Ionians, without taking 

 account of the progress made by the Pythagoreans. 



The ideas of Democritus on the soul and sensation 

 are more interesting. The soul, according to him, is 

 composed of round, extremely tenuous atoms of an 

 igneous nature. Because of their tenuity these atoms 

 continually tend to escape from the body, but 

 respiration constantly renews their number. When 

 this weakens, there is sleep and sometimes lethargy ; 

 when it ceases altogether, death supervenes. As to 

 sensations, these imply a direct contact with objects 

 or emanations coming from them. For example, if 

 we perceive bodies at great distances it is because a 

 group of atoms keeping the shape of these bodies 

 makes an impression on our visual organ. In a more 

 general way, the function of thought is connected with 

 the temperature and mobility of psychical atoms. If 

 the soul is too hot or too cold, it makes an inaccurate 

 representation of reality. 



As a system of philosophy, atomism marks an impor- 

 tant stage in Greek thought. By affirming the existence 

 of empty space, and conceiving Being under the form of 

 immutable atoms, which incessantly unite and separate, 

 the school of Abdera reconciles the theories of Herac- 

 litus with those of the school of Elea. Becoming is 

 not the whole of reality but it is an important part 

 of it. The controversy in which Greek philosophy 

 had been involved from its beginning was thus settled 

 and the dialectics of Plato could come to birth. 



5. MEDICAL SCIENCE 



Between the fifth and sixth centuries B.C. mathe- 

 matics, astronomy and biology separated more and 

 more from philosophical speculations and began to 

 establish themselves as independent sciences. Medical 

 science, however, had not waited until this period to 



