Although it has occasionally been mentioned in some Thomistic studies in recent decades, the collative act of natural estimative has not been the subject of a detailed research. Due to the intrinsic complexity of the particular intentio, formal object of this faculty, its apprehension involves an articulation or collatio between two instances: the condition of the cognizer and the nature of the singular represented by the imagination. This confrontation becomes more complex to the extent that different intentiones come together in the same cognizer, mainly thanks to the operation of memory.