Desktop version

Home arrow Economics arrow Aquinas’s theory of perception: an analytic reconstruction


The Intensity of a Perfection

In his Categories (8, 8b 26-10a 27), Aristotle lists four different kinds in the category of quality. The first type consists of states and dispositions. This is where Aquinas, following Aristotle, places instances of knowledge.[1] The issue of not placing acts of knowing within the category of actions appears to be centred on the question of intensity. Actuality-2 is a more intense ‘having’ of a quality developed from a previously acquired disposition. A piece of knowledge, when exercised, is (for example) when a mathematician is here and now thinking about/teaching/demonstrating the Pythagorean theorem. This is a quality possessed by a knower rather than an action performed by a knower. This analysis is steeped in Aristotle’s account of motion, his definition of change, and his account of the ten categories. Nonetheless, in light of contemporary discussions concerning the philosophy of action in regard to knowledge states, it is interesting philosophically to note that neither Aristotle nor Thomas ascribed the category of action to mental states of knowing, either in sense knowledge or conceptual knowledge.

Aquinas next considers the use of ‘being acted upon’ as applied to Disposition-1.

Then [. . .] Aristotle considers whether the transit from potency to act on one who acquires completely fresh knowledge is an ‘alteration’ in the sense of ‘being acted upon’. He says that when a learner, previously knowing only potentially, is instructed by a master already knowing actually, one should either call this simply a case of alteration and being acted upon, or else distinguish two kinds of alteration. (Commentary On the Soul, no. 369)

Aquinas offers an important distinction:

  • (a) The one kind is a ‘change to a condition of privation’, i.e. into qualities opposed to those which the thing already has, and incompatible with these, and therefore until now excluded by them.
  • (b) The other kind is ‘by change to a possession and maturity’, i.e. through receiving habits and forms which perfect the thing’s nature and involve no loss of what it already has.

It must be noted that the learner is ‘altered’ in this second sense, but not in the first. (no. 369)

The general concern is whether knowledge is an alteration; if it is an alteration, then knowledge would be an instance of a physical activity. But here, as above with the actualization of Disposition-1, Aquinas argues that this is not a strict sense of alteration because this would imply a reduction from one contrary state to its opposite. Rather, the acquisition of Disposition-2/Actuality-1 is a perfection of a knowing being. In other words, a being capable of intentionality is perfected or further developed by the acquisition of both Actuality-1 and Actuality-2. It does not lose any property or quality when it perfects or develops Disposition-1 by acquiring habits of knowledge—i.e. the acquisition of a conceptus.

In this context, it is important to note that Aquinas refers to the process of knowing as an ‘immanent’ activity rather than as a ‘transient’ activity. In his terminology, the root difference between the two is the following: Immanent activity consists essentially in a qualitative perfection of the agent; transient activity, on the other hand, consists essentially in the production of something beyond the agent—i.e. beyond the agent as knower herself.

According to Aquinas, every physical change is an instance of transient action. On the other hand, every intentional act is an immanent action. In the case of knowing, he distinguishes between a transient action and an immanent action. A transient action is a physical change, while an immanent action is intentional in character. The immanent action remains within the agent while the transient action passes out to another thing. It follows from this distinction that intentional acts are not esse naturale, because every change bringing about an esse naturale would be a transient action. Furthermore, every actio humana (e.g. thinking about Scotus on individuation) would be immanent, while every actio hominis (a twitch of the face of the person) would be transient. In the Prima Pars of the Summa Theologiae, Aquinas writes: Sentire et intelligere sunt actiones immanentes’.[2] Often this distinction is blurred and muddled in the early modern discussions of efficient causality as the sufficient condition for the occurrence of perception.

Aquinas is concerned lest any confusion obtain in his denial that a movement from contrary to contrary occurs in the process of knowing. With this concern, he raises the linguistic question about a knower who goes from a state or condition of error to a condition of having true knowledge. Thus, he considers the possibility that the process of the acquisition of knowledge from a previous state of error might be considered as an action. In other words, an acquisition of this kind might be construed as a movement from a contrary state to its opposite—i.e. a process from error to truth. The following passage is instructive of Aquinas’s philosophical method, as the linguistic overtones and the close attention to language are evident.

Ignorance has two meanings. It can be purely negative: for example, when the ignorant person neither knows the truth nor is involved in the opposite error. In this case, the person is simply brought into actual knowledge, not changed by being rid of a contrary habit. On the other hand, ignorance may imply the bad condition of being involved in error contrary to the truth. Then to acquire knowledge, one must be changed by being delivered from the contrary habit. (Commentary on the Soul, no. 363)

Aquinas continues with this argument:

However, when one is brought from error to the knowledge of truth, there is indeed a certain likeness to the change from one quality to its opposite. However, it is only a likeness. For where there is true alteration, both the opposed qualities, which are the terms of the process, are necessarily and essentially involved. For example, when something becomes white, this involves not only white, but also black, or some intermediary color, which in relation to white is a sort of blackness. But where knowledge is acquired, it is quite incidental that the learner was previously in error. She could learn without first being in error. Hence, it is not in the strict sense an alteration. (no. 370; emphasis added)

Aquinas is satisfied that there is no important sense of ‘being acted upon’ which applies to knowledge in the form of an action. Therefore, the process of acquiring and exercising knowledge, i.e. either Actuality-1 or Actuality-2, is never reducible to an alteration in the strict sense. On the other hand, such an acquisition or exercise of knowledge is a perfection or an ‘increased intensity’ of the knower. As a perfection, there is no ‘destruction’ of any function within the knower. Action in a physical sense, therefore, is excluded from Aquinas’s account of concept formation and concept exercise. At root level, this is an indication of ‘intentional’ becoming, which is neither a physical change nor reducible to a physical change. This analysis explains in some detail the development of the ontological principle needed for Aquinas’s thesis of intentionality.[3]

Furthermore, it appears that intentionality is a primitive ontological predicate within Aquinas’s philosophy of mind. The conceptual elucidation of this primitive character is in terms of a qualitative perfection rather than a reduction of potency to act from contraries. Reduction through contraries entails a physical change. Reduction without the contraries in the case of knowing is the ontological characteristic of intentionality in its most generic sense. This is an important claim in Aristotelian philosophy of mind. It teases out the significance of the primitive concept of ‘esse intentionale’, which is the basis of Aquinas’s theory of intentionality. Nonetheless, he does claim that not every case of reduction without contraries would be an intentional awareness. He gives the example of the builder. The builder is not altered when undertaking the act of building. ‘Building, it would seem, is not completely reducible to intentional activity. The precise difference here is unclear. Hence, reduction without contraries is a generic class, of which one type is intentional activity. It may be the case that ‘building’ is an instance of what both Aristotle and Aquinas call a kind of practical reason (phronesis), which would be a practical art. This would be cognitive, of course, but also directed towards the external effect. Theoretical understanding within the speculative realm, however, always remains within as a perfection of the knower as cognitive agent.

  • [1] For an illustrative account of Aquinas’s position on the category of quality, see Anthony Kenny, ‘TheFour Types of Quality’ appendix 3, Summa Theologiae, vol. 22: Dispositions for Human Acts, 115-16.
  • [2] For a comprehensive account of this distinction, see Francis Nugent, ‘Immanent Action in St. Thomasand Aristotle’ New Scholasticism 37(2) (1963), 164-87. See also Anthony Kenny, Philosophy in the ModernWorld (Oxford: Oxford University Press, 2008), 210.
  • [3] This analysis substantiates Haldane’s claim that there is no epistemology without ontology, especiallyas articulated in the texts of Aristotle and Aquinas.
Found a mistake? Please highlight the word and press Shift + Enter  
< Prev   CONTENTS   Next >

Related topics