Modus Revelatio: Aquinas on the Intellect's Apprehension

Aquinas’ doctrine begins with the mode of the intellect’s comprehension of things in general. He argues that any conclusion of the mind requires an absolute and complete understanding of the elements that make up the given studied subject/object. These conclusions are formed from a series of inferences made from the elements as they are perceived by the mind. The tool by which such elements and principles are grasped, Aquinas calls the intellect. In line with the Aristotelian school of thought to which Aquinas subscribed, human cognition derives primarily from sense perception, from which follows, human intellectual cognition. First, the intellect perceives intelligible forms through its own natural light or reason (e.g. that plant growing from the ground is yellow). All men are endowed with this “natural light” of the soul, which gives man the ability to perceive himself, that which is around him, and to make conclusions from that which he observes.
After perceiving the thing observed, man then forms an abstract idea of what is observed (e.g. because the plant is yellow and made up of numerous petals, it may be a daffodil). The intellect joins the various observations together and gauges them against reality and experience. From this process, the intellect makes a conclusion about the thing. The accuracy and essentialness of the conclusion depends on the power and perception of the intellect. Depending on its power, the intellect is assimilated to the essence of the object perceived based on all the ideas it has formed of that object. In other words, a particular intellect is capable of discerning the truth of a given thing observed insofar as it perceives all the full and correct elements of that thing. In this way, one may say that the basic human intellect is infallible in that incorrect conclusions derive from limited perception and observation, rather than from the intellect’s ability to draw conclusions. One begins to see here at the beginning of Aquinas’ discourse on the intellect and revelation the basic premise that not all intellects are equal, as some have greater abilities to attach and assimilate themselves to objects than others.