Katalepsis (Greek:κατάληψις, "grasping") is a term inStoic philosophy for a concept roughly equivalent to moderncomprehension.[1] To the Stoic philosophers,katalepsis was an important premise regarding one's state of mind as it relates to grasping fundamental philosophical concepts, which was followed by theassent, or adherence to the truth thus understood.
According to theStoics, themind is constantly being bombarded with impressions (phantasiai).[2] Some of these impressions are true and some false. Impressions are true when they are truly affirmed, false if they are wrongly affirmed.Cicero relates thatZeno would illustratekatalepsis as follows:
He would display his hand in front of one with the fingers stretched out and say "A visual appearance is like this"; next he closed his fingers a little and said, "An act of assent is like this"; then he pressed his fingers closely together and made a fist, and said that that was comprehension (and from this illustration he gave to that process the actual name ofkatalepsis, which it had not had before); but then he used to apply his left hand to his right fist and squeeze it tightly and forcibly, and then say that such was knowledge, which was within the power of nobody save the wise man.[3]
Katalepsis was the main point of contention between the Stoics and the two schools ofphilosophical skepticism during theHellenistic period: thePyrrhonists and theAcademic Skeptics ofPlato's Academy. These Skeptics, who chose the Stoics as their natural philosophical opposites, eschewed much of what the Stoics believed regarding thehuman mind and one's methods of understanding greater meanings.[4] To the Skeptics, all perceptions wereacataleptic, i.e. bore no conformity to the objects perceived, or, if they did bear any conformity, it could never be known.[5]