INDISTINCTNESS OF IDEAS. 267 



that faculty of prediction (of the motions of the 

 heavens) which belongs to the pupils of Eudoxus, 

 and Hipparchus, and the rest, which some call 

 Astronomy; for that is an observation of pheno- 

 mena, like agriculture or navigation; but against 

 the Art of Prediction from the time of birth, 

 which the Chaldeans exercise." Sextus, therefore, 

 though a skeptic by profession, was not insensible 

 to the difference between experimental knowledge 

 and mystical dogmas, though the former had no- 

 thing which excited his admiration. 



The skepticism which denies the evidence of the 

 truths of which the best established physical sciences 

 consist, must necessarily involve a very indistinct 

 apprehension of those truths ; for such truths, pro- 

 perly exhibited, contain their own evidence, and 

 are the best antidote to this skepticism. But an 

 incredulity or contempt towards the asserted truths 

 of physical science may arise also from the attention 

 being mainly directed to the certainty and import- 

 ance of religious truths. A veneration for revealed 

 religion may thus assume the aspect of a skepticism 

 with regard to natural knowledge. Such appears to 

 be the case with Algazel or Algezeli, who is adduced 

 by Degerando 4 as an example of an Arabian skeptic. 

 He was a celebrated teacher at Bagdad in the ele- 

 venth century, and he declared himself the enemy, 

 not only of the mixed Peripatetic and Platonic 

 philosophy of the time, but of Aristotle himself. 



4 Degerando, Hist. Comp. des Systemes, iv. 224. 



