said to be a criterion; thus Chrysippus again said that ‘the criteria are sensation and preconception,’ and Boethus set up many criteria, as mind, sense, science, and (in practical matters) appetite[89]. [Sidenote: General consent.] =158.= Seeing that the full assurance of truth is not at every moment attainable, it is necessary to be contented from time to time with something less complete. Amongst such tests the ‘general consent of mankind’ plays an important part, especially in connexion with the dogma ‘that gods exist.’ We may indeed well believe that this criterion was not originally suggested by revolutionary philosophers, but rather by conservative advocates of an established religion; and therefore we are not surprised to see it emphasized first by Posidonius and afterwards by Seneca[90]. General consent is however by itself no proof of truth, but at most an indication of the presence of a ‘common notion’ in its rough shape. If however we see that the ‘common notion’ grows stronger and more clear every day, and if it is the more firmly held as men approach the standard of wisdom, it becomes a strong support[91]. [Sidenote: Probability the guide of life.] =159.= From a very early period, as we have already indicated, Stoic teachers accepted probability as the guide of life in its details, being perhaps aided by the happy ambiguity of the expression ‘reasonableness’ (τὸ εὔλογον), which suggests formally the pursuit of reason, but in practice is a justification of every course of which a plausible defence can be brought forward. Ptolemy Philopator, we are told, jestingly put wax fruit before Sphaerus at his table, and when Sphaerus tried to eat it cried out that he was giving his assent to a false mind-picture. Sphaerus replied that he had not assented to the picture ‘this is fruit,’ but only to the picture ‘this is probably fruit[92].’ Antipater of Tarsus, when he explained that the very essence of virtue lay in the choice of natural ends upon probable grounds[93], was felt to be giving way to Carneades[94]. Panaetius justified the maintaining of that which is plausible by the advocate, and Cicero, whose own conscience was not at ease in the matter, was glad enough to quote so respectable an authority on his own behalf[95]. In the Roman imperial period a growing spirit of humility and pessimism led to a general disparagement of human knowledge, centring in attacks on the trustworthiness of the senses. So Seneca speaks of the ‘usual weakness’ of the sense of sight[96], and Marcus Aurelius feels that ‘the organs of sense are dim and easily imposed upon[97].’ The older Stoics had admitted the frequent errors of the senses[98], but they had been confident they could surmount this difficulty. Their latest disciples had lost the courage to do this, and in consequence the practice of ‘suspension of judgment,’ which before had been the exception[99], became with them the rule. Nevertheless