MARCUS TULLIUS CICERO. 221 



nothing was to be known (fcaraXijTrroV)- For the Stoics themselves, 

 their most determined opponents, defined the k-aTaXrjTrriKri fyavraaia 

 (or impression which involved knowledge 1 ), to be one that was 

 capable of being produced by no object except that to which it really 

 belonged. 2 



Since then we cannot arrive at knowledge, we must suspend our 

 decision, pronounce absolutely on nothing, nay, according to Arcesilas, 

 never even form an opinion. 3 In the conduct of life, however, pro- 

 bability" 4 must determine our choice of action ; and this admits of 

 different degrees. The lowest kind is that which suggests itself on 

 the first view of the case (fyavTaaia irtdavri) ; but in all important 

 matters we must correct the evidence of our senses by considerations 

 derived from the nature of the medium, the distance of the object, the 

 disposition of the organ, the time, the manner, and other attendant 

 circumstances. When the impression has been thus minutely con- 

 sidered, the (fxu'TUffia becomes Treptw^i/^tVr?, or approved on circum- 

 spection ; and if during this examination no objection has arisen to 

 weaken our belief, the highest degree of probability is attained, and 

 the impression is pronounced complete (uTrepto-Traoroe.) 5 



Sextus Empiricus illustrates this as follows : 6 If on entering a dark 

 room we discern a coiled rope, our first impression may be that it is 

 a serpent, this is the (pavraaia TviOavrj. On a closer inspection, 

 however, after walking round it (Trtpiocteuo-avrfc) we observe it does 

 not move, nor has it the proper colour, shape, or proportions ; and 

 now we conclude it is not a serpent ; here we are determined in our 

 belief by the Trtpiw^ti^utVr/ fyai'-affia. For an instance of the third 

 and most accurate kind, viz., that with which no contrary impression 

 interferes, we may refer to the conduct of Admetus on the return of 

 Alcestis from the infernal regions. He believes he sees his wife ; 

 everything confirms it ; but he cannot acquiesce in that opinion ; his 



1 Oi yovv STOU/CO! Ka.Ta.\r$iv eTi/cu (paffi /caToA.7?7TT:p (pavrao-iq. ffvyKarddeffiv. 

 Sext. Empir. Pyrrh. Hypot. iii. 25. 



2 " Verum non posse comprehend! ex ilia Stoici Zenonis definitione arripuisse 

 videbantur, qui ait id verum percipi posse, quod ita esset animo impressum ex eo 

 unde esset, ut esse non posset ex eo unde non esset. Quod brevius planiusque sic 

 dicitur, his signis verum posse comprehendi, quae signa non potest habere quod 

 falsum est." (Augustin, contra Acad. 2, 5.) [" They seemed to hare caught their 

 doctrine of the incomprehensibility of truth from that definition of the Stoic Zeno, 

 who says that that may be perceived to be true which has been so impressed on the 

 mind by the cause of its existence, as it could not have been by what was not the 

 cause of its existence, which is thus more briefly and simply expressed : that truth 

 may be comprehended by those marks which falsehood cannot possess." Editor.'] 

 See also Sext. Empir. adv. Math. lib. vii. irepl /nerajSoA-^s, and of Lucullus, 6 with 

 13. Lucullus, 13, 21, 40. 



4 ToTs <$>aivojJi.f:<pQis ovv Trpocre^oires Kara. r}]v ^ICDTIK^JV r^p-^ffiv afio^da'Tcas 

 /Jto-j/zev, eirzl p.i] Svfd/j.eda avevepyrjroi iravra.irc.a'iv elz/at. Sext. Empir. Pyrrh. 

 Hypot. 1, 11. 



5 Cicero terms these three impressions, " visio probabilis ; quse ex circumspectione 

 aliqud et accurate considerations fiat; qua} non impediatur." Lucullus, 11. 



6 Pyrrh. Hypot. i. 33. 



