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Identity of the Knower and the Known

Those who are new to Thomistic psychology and epistemology are often confused by the claim that in the act of knowing, the knower becomes one with the known. Indeed, it is an often misunderstood part of Thomistic epistemology. If this theory is true, then it nicely sidesteps a lot of the epistemological problems that lead to skepticism, solipsism or relativism. The identity of knower and known, then, is to be distinguished from the view that what we know are ideas or sense impressions that are caused by extra-mental realities. The Thomistic view is stronger than the view that our ideas are impressions that are similar to, or the same in kind with, the object of which it is the idea. This other theory (ala John Locke) is often called "indirect realism" because it claims that we do not have direct access to extra-mental reality, but only indirect access, through impressions and ideas. Thus, on the Lockean view, there is a chain of causality: things affect us and our senses producing sense impressions and ideas, and these produce knowledge.

Solipsism and Relativism

There is, then, the obvious problem of knowing that our impressions are true representations of reality. There is no way to check them that does not itself rely on sensation and so is open to the same possibility of error. And since, on this view, one cannot tell if one's senses are delivering accurate information, one has reason to doubt that there is any referent for what one senses. One can reasonably (?) say that there is no extramental object (solipsism), or that there may or may not be an object, and we may or may not observe it accurately (relativism). The Thomistic theory cuts off bad consequences like these before they begin by denying that what we directly (and properly) perceive or know are sense impressions or our own ideas. Instead, what we perceive is the thing, and the sensible species (in the sense organ) is that by which the identity that is perception comes about. It works in an analogous manner for the intellect: what we know is the universal existing in the thing; the idea is that by which we know the universal.

Assimilation and Identification

The summary so far given merely says what the Aristotelian-Thomistic theory is not. It is harder to explain what this (non-Lockean) identity really amounts to and why one ought to believe that Aquinas and Aristotle are right in their theory. The main point in favor of this theory of knowledge is the recognition that both sense knowledge and intellectual knowledge are activities that we engage in. In opposition to the Lockean view, where sense impressions are things that we suffer and undergo, Thomas and Aristotle claim that this is not the essence of sensation, although both admit that there is a passive element in the organs when they are passively affected by the sense object. Thomas and Aristotle believe that sensation is an activity that remains in the one who senses, and is not an activity that passes from an object to the organ. Thus, Aquinas calls it an immanent activity (as opposed to a transitive activity- like the heating of water). Aristotle says that it is a kind of being acted upon or motion, but one that should receive its own name. Like transitive actions, e.g. the heating of water, something receives a new form as the water receives the form heat from the fire. However, in such cases, the form of heat in the water is not the same as the form of heat in the fire, but only the same in kind, being in different parts of matter. Moreover, in the case of the heating of water, the water loses the form that it had before, namely the form of coolness. In the case of sensation, these features do not obtain: the reception is not of a similar form, but of the SAME form; and the reception does not involve the destruction of the pre-existing form, but does involve the fulfillment and completion of the knowing power; and thus, the reception is not into matter, but a kind of immaterial reception. Thus, the knower becomes one with the known, because it IS in a new way, i.e. with the very same form of the thing known, and this happens in an immaterial way that fulfills the knower. What I've said about sensation works the same with the intellect, but the identity is such that it occurs even without an organ, and thus the intellect is immaterial in an even stronger sense than the sense powers.

The Aristotelian-Thomistic account, then, neatly sidesteps indirect realism/phenomenalism that has plagued philosophy since Descartes. It claims that we directly know reality because we are formally one with it. Our cognitive powers are enformed by the very same forms as their objects, yet these forms are not what we know, but the means by which we know extramental objects. We know things by receiving the forms of them in an immaterial way, and this reception is the fulfillment, not the destruction, of the knowing powers.

The Fit with Materialism

The theory is not without its problems and it is not entirely clear that it accords with other things we know about the world, because as a corollary to the theory, Aristotle and Thomas seems to be making the claim that what really happens in perception is nothing that can be empirically verified in the way other material interactions can be verified. Precisely because perception is an immaterial, immanent action, it is of a different kind than transitive actions, which is what their theory would claim scientific observation can detect. Thomists tend to believe that such a consequence is not fatal to the viability of this identity theory since they would also claim that the very life of living things cannot be totally explained, as modern science tries to do, by appealing only to microscopic parts in interaction (bio-chemistry). And yet it seems a matter of intuitive experience that an organism is more than the parts working together (for an organism that has just died has all the same parts). Thus, although modern chemistry and biology no doubt make true and illuminating observations about some of the mechanisms by which living things live and have perception, that sort of explanation does not totally capture the whole of what it means to live and perceive. Thus, the appeal to souls and immaterial reception of form is an irreducible and ineliminable source of explanation.

For Further Information

There are fuller explanations of these points with reference to the works of Aquinas and Aristotle at the page Psychic Powers.

The following are some books on the subject:

  • Frederick Wilhelmsen, Man's knowledge of reality; an introduction to Thomistic epistemology. (Englewood Cliffs, NJ: Prentice Hall, 1956).
  • Georges van Riet, Thomistic epistemology. (St. Louis: B. Herder, 1963).
  • Fernand van Steenberghen, Epistemology. (NY: J. F. Wagner, 1970). Louis Marie Regis, Epistemology. (NY: Macmillan, 1959).
  • Joseph Owens, Cognition: an epistemological inquiry (Houston, TX: Center for Thomistic Studies, 1992).

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