 A new question then emerges: what is the difference between sensory perception and understanding? Pereira’s answer was that there are not diverse instances of knowledge but rather a unique process that progressively reaches various stages of refinement. Basing himself on the Preface of Aristotle’s Physics, he examined these various stages through which the universal concept would pass (AM: I.439–441). This concept can be confused or distinct: the confused concept is that which covers a complete genus without any distinction of the species contained therein, while the distinct one is precisely that which defines the designated object with all the categories that belong to it. There are then two forms of knowledge: one of them is less subtle because it rests upon the mere assertion of the existence of an object, and the other is subtler because it distinguishes with clarity all the elements that are present in it. Given the nature of our own cognitive potentiality, it is always easier to have access to the first type of universal cognition; only through effort and exercising shall we be able to achieve a greater determination in our own understanding.