CHAP, v.] THE NATURE OP MEMORY. 211 



circle,' esLch of these demonstrations has its peculiar subjects, 

 and parts of the sciences, wherein they are of force, and 

 others again from which they are excluded ; for insisting 

 upon too strict proofs in some cases, and still more the faci- 

 lity and remissness in resting upon slight proofs in others, is 

 what has greatly prejudiced and obstructed the sciences. 

 And so much for the art of judgment. 



CHAPTER V. 



Division of the Eetentive Art into the Aids of the Memory and the 



Nature of the Memory itself. Division of the Doctrine of Memory 



into Prenotion and Emblem. 



"We divide the art of memory, or the keeping and retain- 

 ing of knowledge, into two parts ; viz., the doctrine of helps 

 of several subjects analogical to the one proposed, and thence proceeds 

 to draw the inference that such attribute enters also into the subject in 

 question. In addition to these three last kinds of mediate positive 

 proof, there are three others, which may be called mediate negative ; 

 viz., 1. d postevioH, which in inferring conclusions erroneous from the 

 contradictory of that which is sought to be maintained, shows that the 

 opposition is formed on false principles, and establishes the truth of 

 their contradictories. 2. a priori, which in showing that the contra- 

 dictory of the original proposition is a necessary consequence of some 

 exploded principle, and also contradictory to the principle of which the 

 contested proposition is also a consequence, infers the truth of such pro- 

 position with the principle of which it is a corollary. 3. d latere, whose 

 object is to show that the attribute diametrically opposite to the one in 

 question, agrees with a subject also diametricsJly opposite to the one 

 proposed, that the last attribute may be inferred to agree with the 

 last subject, Ed. 



• Bacon seems to imply that Aristotle not only admitted demonstration 

 in a circle, but even understood it in the sense of analogical proof or 

 demonstration a latere; whereas the Stagyrite only introduced the term 

 for the purpose of controverting it. Some of the ancient materialists, 

 in order to rid themselves of the illogical consequences of a series of 

 proofa ad infinitum, in which the denial of first principles involved them, 

 asserted the possibility of demonstrating all things from each other, a 

 line of argument in which the chain of proof would run into itself : 

 dWa 7rdvTU)v (Ivai, aTroSn^iv ovSkt' KcoXvei' ivCi\tTai yap kvkX*^ 

 yivkaQai rijv diro^tiiiv Kal t^ dXXj'/Xaiv. (Arist. Anal. Post. i. 3.) The 

 Stagyrite, however, confronted this assertion with the reason, that de- 

 monstration could only be effected by evolving new truths out of things 

 prior and more known, and pronounced the formatioii of a body of sci- 

 entific truths without admitting first principles more palpable to tha 

 mind than any proof could make them, impossible. See, also, Arist. 

 Ajialyt. Pri. ii. 6, 1. Ed. 



p2 



