Epistemology
Epistemology
“Epistemology” means theory of knowledge, and unlike his predecessors, Aquinas’ interest was something more like a description of the process of achieving knowledge. He began his metaphysics with the statement that all humans desire to know, and that the distinguishing feature of human beings is that we can think. That we are intellectual beings---for better or for worse---had much to do with his conception of humans’ relationship with God.
The beginning of the process of knowing was, like for Aristotle, sensory perception. Sensory cognition is the foundation of his epistemology. Our senses are merely a beginning, by making us aware of the material world around us. Knowledge is the ultimate goal. The senses (sight, smell, hearing, touch, sound), though trustworthy when they function normally, do not meet the requirements for knowledge. They cannot in and of themselves perceive the completeness of the thing being perceived. Both external sense and internal senses are required to grasp knowledge of something in its completeness. The external senses cannot meet up to the criteria for knowledge, which Aquinas, after Plato and Aristotle, defines as universal, immaterial, and immutable.
The senses can’t grasp an object in universal terms. I may see and hear and smell a horse and say that galloping, spotted thing is a horse, but I do not really know this thing I have seen, because my senses do not provide knowledge in the fullest sense. Aquinas describes in detail the stages of the process of arriving at knowledge.
Seeing, smelling, and hearing the horse is the first stage in the process. Our sense organs receive the sight, sound, and smell of the horse. These qualities come to reside in the sense powers as de-materialized forms, different than the matter of the horse when first perceived.
They are now what Aquinas calls ‘species.’ The internal senses come into play to, in effect, organize the data taken in by the sense powers. Those are known as the ‘common sense’ powers. The cognitive process proceeds to the next step, the making of a likeness to the complete, individual object, or what Aquinas calls the ‘phantasm’---the non-material but likeness of the horse.
The notion that knowledge must come from the things themselves was new in Aquinas’ day. Empirical knowledge was by-passed by appealing to a higher power, a divine idea (Plato) or a prior source. Aquinas believed the human mind’s ‘nobler’ element enabled it to abstract valid universals form sense impressions. Aquinas’ empiricist approach, along with his theological convictions and experience, convinced him that things can be known within sensory experience. The agent intellect is required to find the universal in the horse we perceive and to have knowledge of things that are immaterial.
The horse’s potential intelligibility becomes actually intelligible in the process of our coming to know the horse. This process he calls ‘intellectual apprehension.’ Our external senses sort the horse’s characteristics based on the impression it makes on each sense organ. Our internal senses (common sense and imagination) and intellect put the horse back together as the complete individual object (phantasm), and then into intelligible species or the nature of the horse, or ‘the form by which the intellect understands.’
For Aquinas and Aristotle something is apprehended or it is not. To complete its cognition of the horse the intellect must turn back to the lower sensory powers. Why? There is much difficult and obtuse terrain in answers to those questions. We jump in the process to the knowledge of the nature that all horses share as well as to this horse we first spotted. Aquinas insists we must turn to the phantasm in the process in order to know the relationship between the universal and the horse we perceive.
Aquinas maintained that the attainment of knowledge is gradual and we can be wrong, of course. There is much to know about the galloping horse: its breed, its size, its habitat, it health, its gender, age, etc. With our intellects we can reason as the key to knowledge, but perfect knowledge is beyond human attainment. To know one thing perfectly is to know the truth about it perfectly. For Aquinas, to know the horse perfectly would require we know its matter, form, maker, and its purpose.
Aquinas’ epistemology was derived from his weightier theological concerns. In Aquinas’ view human striving to know was possible because things, humans themselves, and human knowledge of things were expressive of the absolute being---God. From God who contained the eternal template of all things, humans derive truth. Humans became more like God by growing in knowledge, and to be more like God, according to Aquinas, was the desired end of all humankind.