In this way what had formerly been followed only by tacit agreement, and instinctively, would be consciously recognised and formally expressed. By degrees, more or less perfect expressions were found for the fundamental principles of logic, such as the principles of contradiction, sufficient reason, excluded middle, the dictum de omni et nullo, as well as the special rules of the syllogism, as for example, ex meris particularibus aut negativis nihil sequitur, a rationato ad rationem non valet consequentia, and so on.
Horretara, ordu arte isileko adostasunez jarraitu eta instintuaren arabera praktikatu zena, orain kontzientziarekin legetzat berrezagutu eta formalki adierazi nahi zen bezala, pixkanaka gero eta adierazpen gutxi-asko perfektuak aurkitu ziren oinarri-printzipio logikoetarako, hala nola, kontraesan printzipioa, behar besteko arrazoiaren printzipioa, hirugarrena baztertzearena, [guztiaz eta bakarraz esana], baita silogistikaren arau espezialagoak ere, adibidez, [premisa partikular soiletatik edo negatibo soiletatik ez da ezer segitzen;