NOVUM ORGANUM 27 



called alteration, but in fact a change of position in the 

 smallest particles) is equally unknown ; and yet, unless the 

 two matters we have mentioned be explored and brought 

 to light, no great effect can be produced in nature. Again, 

 the very nature of common air, and all bodies of less den 

 sity (of which there are many) is almost unknown; for the 

 senses are weak and erring, nor can instruments be of great 

 use in extending their sphere or acuteness all the better 

 interpretations of nature are worked out by instances, and 

 fit and apt experiments, where the senses only judge of the 

 experiment, the experiment of nature and the thing itself. 



LI. _The_human u nderstanding_J8 r by its owrt nature, 

 prone to abstraction, and supposes that which is fluctuating 

 tcTbelixed. But it is better to dissect than abstract nature: 

 such was the method employed by the school of Democ- 

 ritus, 18 which made greater progress in penetrating nature 

 than the rest. It is best to consider matter, its conforma 

 tion, and the changes of that conformation, its own action, 19 

 and the law of this action or motion ; for forms are a mere 

 fiction of the human mind, unless you will call the laws of 

 action by that name. ao 



18 Democritus, of Abdera, a disciple of Leucippus, born B.C. 470, died 360; 

 all his works are destroyed. He is said to be the author of the doctrine of 

 atoms : he denied the immortality of the soul, and first taught that the milky 

 way was occasioned by a confused light from a multitude of stars. He may 

 be considered as the parent of experimental philosophy, in the prosecution of 

 which he was so ardent as to declare that he would prefer the discovery of one 

 of the causes of natural phenomena, to the possession of the diadem of Persia. 

 Democritus imposed on the blind credulity of his contemporaries, and, like 

 Roger Bacon, astonished them by his inventions. Ed. 



9 The Latin is actus purus, another scholastic expression to denote the 

 action of the substance, which composes the essence of the body apart from its 

 accidental qualities. For an exposition of the various kinds of motions he con 

 templates, the reader may refer to the 48th aphorism of the 2d book. Ed. 



20 The scholastics after Aristotle distinguished in a subject three modes of 



SCIENCE Vol. 22 2 



