Fernando Lisboa @ peirce-l (referencia bibliografica 'on demand') : The first division of Being were thought to be between "ens reale" " independent of mind " and "non ens" or "ens rationis"" dependent of mind, which wouldn't exist without the mind. The "ens rationis" were still divided into perceptive "ens rationis", shared both by animals and wo/men, and intellectual or conceptual "ens rationis", specific to wo/men. How does a thing come to be a concept? The thing is printed in the mind through perception: according to the relation between the perception and the thing, the impression would be called "notitia", "representatio" or "idolum", "similitudo", "imago" or "phantasma" ("ghost"). The "phantasma" it's a perceptual constructo that provides material for cognition and, as far the "phantasma" comes from perceptive conscience, it is still a "quidditas" and, thus, includes the minute particularities of the perceived thing. It is the passive image of such concrete thing and, thus, conveys, solely, a "species sensibilis". The active intelligence deprive this "species sensibilis" of all its minute particularities and offers to the passive intelligence a form that can be applied to any thing that possesses the originary thing's same nature and substance: a "species expressae": the concept.