Full Idea
Dogmatists say something can be its own criterion. The straight is the standard of itself, and a set of scales establishes the equality of other things and of itself, and light seems to reveal not just other things but also itself.
Gist of Idea
Some things are their own criterion, such as straightness, a set of scales, or light
Source
Sextus Empiricus (Against the Mathematicians [c.180], 442)
Book Reference
'The Stoics Reader', ed/tr. Inwood,B/Gerson,L.P. [Hackett 2008], p.3
A Reaction
Each of these may be a bit dubious, but deserves careful discussion.