Note 23 — Chapter V · LOGIC OF THE STOICS.

(b) Conceptions formed from perceptions. It follows, as a necessary corollary from this view, that the Stoics regarded sensation as the only source of all perceptions: the soul is a blank leaf, sensation is the hand which fills it with writing. But this is not all. Perceptions give rise to memory, repeated acts of memory to experience,23 and conclusions based on experience suggest conceptions which go beyond the sphere of direct sensation. These conclusions rest either upon the comparison, or upon the combination of perceptions, or else upon analogy;24 some add, upon transposition and contrast.25 The formation of conceptions by means of these agencies sometimes takes place methodically and artificially, at other times naturally and spontaneously.26 (α) Κοιναὶ ἔννοιαι formed naturally. In the latter way are formed the primary conceptions, προλήψεις or κοιναὶ ἔννοιαι, which were regarded by the Stoics as the natural types of truth and virtue, and as the distinctive possession of rational beings.27 To judge by many expressions, it might seem that by primary conceptions, or κοιναὶ ἔννοιαι,28 innate ideas were meant; but this view would be opposed to the whole character and connection of the system. In reality, these primary conceptions, or κοιναὶ ἔννοιαι, are only those conceptions which, by reason of the nature of thought, can be equally deduced by all men from experience; even the highest ideas, those of good and evil, having no other origin.29 The artificial formation of conceptions gives rise to knowledge, which is defined by the Stoics to be a fixed and immovable conception, or system of such conceptions.30 Persistently maintaining, (β) Knowledge formed artificially. on the one hand, that knowledge is a system of artificial conceptions, impossible without a logical process, they must, on the other hand, have felt it imperative from this platform that knowledge should agree in its results with primary conceptions,31 agreement with nature being in every department their watchword. For them it was as natural to derive support for their system from a supposed agreement with nature, as it was easy for their opponents to show that this agreement with nature was imaginary, and that many of their assertions were wholly opposed to general opinions.32