with the physical; and then they designate the whole under the names of the criterion of the truth, and a discussion on principles, and elements. And they say that the physical division is conversant about production, and destruction, and nature; and that the ethical division has reference to the objects of choice and avoidance, and lives, and the chief good of mankind.
XX. Dialectics they wholly reject as superfluous. For they say that the correspondence of words with things is sufficient for the natural philosopher, so as to enable him to advance with certainty in the study of nature.
Now, in the Canon, Epicurus says that the criteria of truth are the senses, and the preconceptions, and the passions. But the Epicureans, in general, add also the perceptive impressions of the intellect. And he says the same thing in his Abridgment, which he addresses to Herodotus, and also in his Fundamental Principles. For, says he, the senses are devoid of reason, nor are they capable of receiving any impressions of memory.