Nature is made up of substances composed of matter and form. The subject is the element that identifies and form is the principle of universality. To know is to grasp the ways, as Aristotle correctly said, all knowledge begins with the senses. The process of knowledge is as follows:
a) The senses grasp particular objects, which are recorded in the imagination or fantasy, giving rise to images or print sensitive species. " These images are still signs or characteristics of the objects that come. The images are universal and form is only found in power.
b) Through a process of abstraction, the agent intellect robs those images containing the specific and removes the "forms." Rise of the "intelligible species printed"
c) Understanding agent passes these forms to understanding liability, which receives and acknowledges the necessary essences of all individuals of a species, "express intelligible species."
These are the concepts that allow us to reason and make judgments.
d) Finally, understanding turns its gaze to the image and it recognizes the individual to which the concept can be applied universally.
Things can be in two ways: as a first concrete things or substances, or substances or second thoughts. For Thomas, the knowledge is to abstract the form of concrete things, which makes it subject individual beings. The abstraction falsifies the reality and affirms the existecia separately the individual subject. Human knowledge lies in the separation of form at the intellectual level.
Form can be viewed in three ways:
-In re, as a form of the thing itself is there.
Post-rem, so presentation in human understanding. The form is abstracted and dematerialized.
"Before rem, as is the way the forms are in the mind of God. Before being dematerialized.
The procedure of abstraction of understanding guarantees the truth of intellectual knowledge. Things are the measure of human truth and the truth is the fit between reality (the thing) and understanding, but things are measured by the understanding of God, and that his understanding is the measure of all that exists.