Acatalepsy

Acatalepsy (from the Greek α̉-, privative, and καταλαμβάνειν, to seize), in philosophy, is incomprehensibleness, or the impossibility of comprehending or conceiving a thing. Acatalepsy is the incomprehensibility of all things. It is the antithesis of the Stoic doctrine of katalepsis or Apprehension. According to the Stoics, katalepsis was true perception, but to the Pyrrhonists and Academic Skeptics, all perceptions were acataleptic, i.e. bore no conformity to the objects perceived, or, if they did bear any conformity, it could never be known.

For the Academic Skeptics acatalepsy meant that human knowledge never amounts to certainty, but only to probability. For the Pyrrhonists it meant that knowledge was limited to the appearances (phantasiai) and the pathē. The Pyrrhonists attempted to show, while Academic skeptics asserted an absolute acatalepsia; all human science or knowledge, according to them, went no further than to appearances and verisimilitude.

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