As regards the theoretical, the faculty of a pure rational cognition a priori could be easily and evidently proved by examples from sciences (in which, as they put their principles to the test in so many ways by methodical use, there is not so much reason as in common knowledge to fear a secret mixture of empirical principles of cognition).
Alde teoretikoari dagokionez, apriorizko arrazoimen-ezagupen huts baten ahalmena zientzietatik hartutako adibideen bidez (horietan euren printzipioak era ezberdinetan erabilera metodikoaren bidez probatzen direnez, ez dute ezagutza arruntean bezain erraz arduratu behar ezagupen-oinarri enpirikoen nahasketa sekretuez) froga daiteke erraz eta nabarmenki.