Aristotle, De anima, 427a21-22: ‘Indeed the ancients say that understanding (phronein) and perceiving (aisthanesthai) are the same’.
Why did anybody identify one thing to another? In normal circumstances, two things are identified for correcting the error of dividing them. It is admitted that the reason of dividing and also that of identifying them are inscribed in the things themselves. For the expression ‘the things themselves’ is a source of ambiguity caused by the fact that one thing in itself cannot become a matter of knowledge, we should say that the things come to their knower in the manner of suggesting identity or division. From this point of view, there cannot be any error in identifying things instead of dividing them. It is only the choice of one of those two aspects that come together from the things envisaged.
Could the ancients identify the perception and understanding because of the error of those who divide them? It is a lecture contrary to previous Aristotle’s statements that the same identification occurs in the common knowledge. Hence, we might concede that the old philosophers identified them since they choose that aspect of perception and understanding that suggests identification, instead of choosing the one that suggests division.
The division is suggested only when we consolidate understanding as a method of knowledge, when we find a definite language charged to signify the understanding of things, or when we assume that man himself may separate from himself the activity of thinking. It will result that the ancients used rudimentary means of knowledge. This statement is certainly true if we compare Heraclitus’ fragments with Aristotle’s scientific treatises. But it misunderstands that the identification was not the outcome of ignorance, as if it would appear from the void of ignorance, but it is the result of a deliberate choice of preferring the common aspect of understanding and perception, or we may say that the ancients keep the double meaning of aisthesis: both perception and understanding.
The choice of identification conspicuously appears in Heraclitus’ fragment 125: ‘of things which involve sight, hearing and knowledge (mathesis), these I especially respect (protimeo)’. Protimeo is a conscientiously preference of perception, conjoined with the correspondent of Aristotelian understanding: mathesis. But mathesis is not episteme, the knowledge in its more ample form, so that it could claim the division of understanding from perception. Mathesis is the knowledge possessed by one who learns from the things and by learning he accepts leaving back the cognitive eagerness to impose himself over the things to be known.
For this reason, Aristotle designates understanding as phronein, a form of knowledge that has to do more with that knowledge placed on the level of things, waiting for their suggestions or signs, as it does phronesis as practical knowledge in Aristotelian moral treatises. On this level, Heraclitus’ protimeo finds an answer from Empedocles’ belief in the presence of things as a condition for wisdom, which is quoted by Aristotle in the next lines of the passage.
Thus, the identity between understanding and perception is a view of things and an interpretation of man’s attitude to them, not a rudimentary knowledge. Nonetheless, their division has also to give an account of these two characteristics.