Boast and false appearance

Meaning

False boasting names the pseudo-philosophers' claim to know the art. The main treatise contrasts their self-advertisement with the supposedly truthful writings of the authorities just listed. The impostors use those writings as a cover for deception, making people gape and casting a blue mist before their eyes. The charge concerns a mismatch between asserted knowledge and actual understanding, not speech or publicity as such: the author himself is about to publish instruction. It is also an attributed polemical judgment, not independent proof that every rival practitioner was fraudulent.