קטלפסיס (יוונית: κατάληψις, “grasping”) is a term in Stoic philosophy for a concept all but equivalent to modern הֲבָנָה. לפילוסופים הסטואים, קטאלפסיס was an important premise almost one’s let pass of mind as it relates to grasping fundamental philosophical concepts, which was followed by the לְהַסכִּים, or duty to the firm thus understood.

According to the Stoics, the mind is permanently being bombarded subsequent to impressions (פנטזיה). Some of these impressions are authentic and some false. Impressions are legal when they are in fact affirmed, false if they are wrongly affirmed. Cicero relates that Zeno would illustrate קטאלפסיס כְּדִלקַמָן:

קטלפסיס was the main reduction of contention surrounded by the Stoics and the two schools of philosophical non-belief during the Hellenistic period: the Pyrrhonists and the Academic Skeptics of Plato’s Academy. These Skeptics, who chose the Stoics as their natural philosophical opposites, eschewed much of what the Stoics believed on the order of the human mind and one’s methods of promise greater meanings. To the Skeptics, all perceptions were acataleptic, i.e. bore no understanding to the objects perceived, or, if they did bear any conformity, it could never be known.