References from Cicero's "Academic Questions":
But when practice and skill are added, so that one's eyes are charmed by a picture, and one's ears by songs, who is there who can fail to see what great power there is in the senses? How many things do painters see in shadows and in projections which we do not see? How many beauties which [pg 033] escape us in music are perceived by those who are practised in that kind of accomplishment? men who, at the first note of the flute-player, say,—That is the Antiope, or the Andromache, when we have not even a suspicion of it. There is no need for me to speak of the faculties of taste or smell; organs in which there is a degree of intelligence, however faulty it may be. Why should I speak of touch, and of that kind of touch which philosophers call the inner one, I mean the touch of pleasure or pain? in which alone the Cyrenaics think that there is any judgment of the truth, because pleasure or pain are felt. Can any one then say that there is no difference between a man who is in pain and a man who is in pleasure? or can any one think that a man who entertains this opinion is not flagrantly mad?
AQ 2: XXIV.
What do you think of the Cyrenaic School? philosophers far from contemptible, who affirm that there is nothing which can be perceived externally; and that they perceive those things alone which they feel by their inmost touch, such as pain, or pleasure. And that they do not know what colour anything is of, or what sound it utters; but only feel that they themselves are affected in a certain manner.
AQ 2: XLVI
I come now to the third part of philosophy. There is an idea advanced by Protagoras, who thinks that that is true to each individual which seems so to him; and a completely different one put forward by the Cyrenaics, who think that there is no such thing as certain judgment about anything except the inner feelings: and a third, different from either, maintained by Epicurus, who places all judgment in the senses, and in our notions of things, and in pleasure. But Plato considered that the whole judgment of truth, and that truth itself, being abstracted from opinions and from the senses, belonged to the province of thought and of the intellect. Does our friend Antiochus approve of any of these principles? He does not even approve of those who may be called his own ancestors in philosophy: for where does he follow Xenocrates, who has written a great many books on the method of speaking, which are highly esteemed?—or Aristotle himself, than whom there is no more acute or elegant writer? He never goes one step without Chrysippus.