Lives of Eminent Philosophers 7.51 — Diogenes Laërtius on the Stoics

Diogenes Laërtius, Lives of Eminent Philosophers 7.51

Reported speech · Diogenes Laërtius on the Stoics

According to them some presentations are data of sense and others are not: the former are the impressions conveyed through one or more sense-organs; while the latter, which are not data of sense, are those received through the mind itself, as is the case with incorporeal things and all the other presentations which are received by reason. Of sensuous impressions some are from real objects and are accompanied by yielding and assent on our part. But there are also presentations that are appearances and no more, purporting, as it were, to come from real objects. Another division of presentations is into rational and irrational, the former being those of rational creatures, the latter those of the irrational. Those which are rational are processes of thought, while those which are irrational have no name. Again, some of our impressions are scientific, others unscientific: at all events a statue is viewed in a totally different way by the trained eye of a sculptor and by an ordinary man.