Note 17 — Chapter V · LOGIC OF THE STOICS.

(a) Perceptions the result of impressions from without. The origin of all perceptions (φαντασίαι) may be referred to the action of some object (φανταστὸν) on the soul,17 the soul at birth resembling a blank page, and only receiving definite features by experience from without.18 By the elder Stoics, this action of objects on the soul was regarded as grossly material, Zeno defining a perception to be an impression (τύπωσις) made on the soul,19 and Cleanthes took this definition so literally as to compare the impression on the soul to the impression made by a seal on wax.20 Being himself a very exact pupil of Zeno, Cleanthes probably rendered the views of Zeno correctly in this comparison. The difficulties of this view were recognised by Chrysippus, who accordingly defined a perception to be the change (ἑτεροίωσις) produced in the soul by an object, or, more accurately, the change produced thereby in the ruling part of the soul;21 and whereas his predecessors had only considered sensible things to be objects, he included among objects conditions and activities of the mind.22 The mode, however, in which the change was produced in the soul did not further engage his attention.