Full Idea
Sceptics say that there is either an infinite regress of ideas based on one another, or things come to a stop at primitives which are unknowable (because they can't be demonstrated).
Gist of Idea
Sceptics say justification is an infinite regress, or it stops at the unknowable
Source
Aristotle (Posterior Analytics [c.327 BCE], 72b09)
Book Reference
Aristotle: 'Posterior Analytics (2nd ed)', ed/tr. Barnes,Jonathan [OUP 1993], p.5
A Reaction
This is one strand of what eventually becomes the classic Agrippa's Trilemma (Idea 8850). For Aristotle's view on this one, see Idea 562.
Related Ideas
Idea 562 Axioms are the underlying principles of everything, and who but the philosopher can assess their truth? [Aristotle]
Idea 8850 Agrippa's Trilemma: justification is infinite, or ends arbitrarily, or is circular [Agrippa, by Williams,M]