Lonergan and Aquinas: Isomorphism and Proportionality

by Br. Dunstan Robidoux OSB

The Thomism of Lonergan’s philosophy and theology is accepted by some and rejected by others. On the one hand, Lonergan says about himself that he spent eleven years “reaching up to the mind of Aquinas.” Some of his writings are replete with references to Aquinas. But, at the same time, others argue that something is very wrong with Lonergan’s study of human cognition (his intentionality analysis). Lonergan is accordingly often referred to as a Kantian. He is seen as a promoter of subjectivism and so, as a Kantian, it is said that, in Lonergan, no joining exists between subjectivity and objectivity. From Lonergan’s subjectivity, one cannot move into objectivity. Metaphysics has no foundation.

Now, in addressing this question, it has to be admitted that a fully adequate discussion is no small undertaking. One would have to understand Kant’s own position thoroughly before entering into a similar study of both Aquinas and Lonergan and about how the thought of all these thinkers relates. Such a project cannot be attempted here. However, in order to raise a few questions and to suggest where lines of convergence can possibly be detected, I would like to speak about Aquinas and Lonergan in terms of a number of restricted issues and topics. My presupposition will be the thesis that Lonergan’s thought is not as original as some would believe. In order to understand Lonergan’s thought, one best begins with Aquinas. While some admittedly argue that, to understand Aquinas, one best begins with Lonergan, I will argue to the converse. By reading Aquinas, one best creates conditions that will lead to a better understanding of Lonergan’s thought and a grasp of its true significance.

In Lonergan’s Insight: A Study of Human Understanding, principally in the context of a discussion which speaks about metaphysics as science, it is argued that an isomorphic structure exists between knowing and being. Or, in the words of a more traditional language, a connatural relation exists between the order of human knowing, on one side, and the order of being or reality, on the other. For every element that can be distinguished in the structure of human cognition, a correlative element can be identified in the structure of the known (a known which Lonergan refers to as “proportionate being”). Every metaphysical element is grounded in a corresponding element or act that, as individual, is partially constitutive of the knowing which belongs to human cognition. In Insight (and elsewhere), Lonergan argues against a theory of knowledge which alleges that human knowing is some kind of simple, single act (i.e., a species of intuition). On the contrary, human knowing is complex and, at times, cumbersome. It is constituted by a number or a series of different acts that have each different natures and which are all related to each other in a self-assembling pattern that is normative for human beings. Where Lonergan speaks about experiencing, understanding, and judging as three levels that succeed and sublate one another in the structure of human knowing, three correlative metaphysical components can be distinguished in terms of potency, form, and act. A critical metaphysics is grounded or established on the basis of a critical understanding of human cognition–an understanding that is arrived at through a very personal form of inquiry which emphasizes the importance of self-understanding. Begin an inquiry into metaphysics by first developing a strategy of inquiry which leads toward self-understanding.However, given Lonergan’s theory of an isomorphic relation between the structure of human knowing and the structure of what is known (which can be articulated in a much more sophisticated fashion than what is given here), let us look at Aquinas’s notion of proportionality as this relates to what he has to say about how human knowing is related to what human knowing is able to know. On understanding this notion of proportionality (as Aquinas understood it through his own acts of understanding), one can then think about it and ponder it and ask if a connatural relation exists between it and Lonergan’s theory of isomorphic relations. Is Lonergan’s theory of isomorphism a development of Aquinas’s notion of proportionality?

With respect then to Aquinas’s notion of proportionality, it should be noted that Aquinas begins with an understanding which Aristotle had had. “It is as ridiculous to say, the soul alone understands, as to say, alone it builds or weaves.” Cf. De Veritate, q. 19, a. 1. Knowing is a co-operative effort. It involves both soul and body since human knowing occurs in a being that is formed by two principles. Soul (anima) is united to body (corpus) whereby the soul takes a body and then converts it into a certain kind of body which lives and functions as a result of the soul’s causality. Cf. Summa Theologiae, 1a, q. 75, a. 1. The body is needed by the soul if the soul’s intellectual operations are to occur. Cf. Summa Theologiae, 1a, q. 84, a. 4. Hence, human beings exist as incarnate spirits. Anima mea non est ego. “My soul is not I.” Cf. Expositio et Lectura super Epistolas Pauli Apostoli, In II ad I Cor., 15, lect. 2, no. 924. The soul gives a form or structure to the materiality of the body in order to order the body to the soul and, from this form or structure, the knowing of the human soul derives its characteristic form or structure. Cf. Summa Contra Gentiles, 2, 83, 26. Human knowing emerges as a function of the structuring of the human soul in terms of how human beings exist as embodied beings.

Hence, given the structure or nature of human knowing, Aquinas argues that certain conclusions can be properly drawn about a relation or proportion which exists between knowing and being. As Aquinas notes in the Summa Theologiae, 1a, q. 12, a. 4:

A thing is known by being present in the knower but how it is present is determined by a knower’s way of being. How something knows depends on how it exists. Hence, if the way of being of a thing which is to be known is beyond what belongs to a knower, knowing such a thing would be beyond the natural power [or natural potency] of the knower.

Cognitive activity, as performed by human beings, has its own proper object (specified as an intelligibility that exists within matter). “A thing’s mode of knowing depends on its mode of being. But our soul, as long as we live in this life, has its being in corporeal matter; hence, naturally, it knows only what has a form in matter, or what can be known by such a form.” Cf. Summa Theologiae, 1a, q. 12, a. 11. Between the mode of being and the mode of knowing, a proportion, proportio, or correlation can be discovered and this proportion between the mode of a subject’s being and the mode of its knowing carries over into a proportion that is reflected in the order of being or reality which is the subject matter of ontology or metaphysics.

In different texts Aquinas speaks about a proportionality in the structure of knowing. One text in the Summa Contra Gentiles, 2, 96, 5 directly speaks about proportionality when it says that “the mode of a thing’s proper operation corresponds proportionately to the mode of its substance and nature.” Italics mine. And then, with respect to a proportion which exists between the order of knowing and an order or structure in that which is known, in the In 4 Scriptum super libros sententiarum. d. 49, q. 2, a. 1, ad 6, an earlier text, Aquinas refers to a proportion which should exist between the order or structure of knowing and a like order which should exist in the order of what can be properly and connaturally known. “The potency of the one knowing has to be on a level with the knowability of the thing known.” In the Super Boetium De Trinitate, q. 1, a. 2, ad 3, the same kind of point is reiterated when it said that “some kind of proportion is needed between the knowing power which exists in a knower and what is known as a knowable object.” The reason given is that “the knowable object exists as a kind of actuality within the knowing power of a knower.” Later texts in the Summa Theologiae, 1a, q. 84, a. 7; a. 8; q. 85, a. 1; and a. 8 specify how a connatural, proportional relation should be understood to exist between human knowing and what a human knower knows. A proportion or correlation naturally and properly exists between the embodiment of the human soul (the soul informing a body) and the embedded existence of forms within matter which are the proper object of human knowing. As Aquinas goes on to note in the Summa Theologiae, 1a, q. 88, a. 1, “our intellect in its present state of life has a natural relationship to the natures of material things,” or, more precisely, as Aquinas states it in Summa Theologiae, 1a, q. 108, a. 5, “something is said to be in a certain thing by the proper mode when it is adequate and proportionate to its nature.” Cf. Frederick E. Crowe in Three Thomist Studies, ed. Fred Lawrence, p. 223, nn. 51-52.

With respect to human beings then, and also with respect to angels and God, a distinct strict proportion exists between the knowing of a certain type of subject, on the one hand, and what is being known by the same subject, on the other hand. In the context, for instance, of a strict proportion which exists between a created intellect and a created form, a created intellect can possibly come to exhaustively understand a created form but, with respect to an uncreated form, this is impossible. Cf. Lectura super Ioannem 1, 18, lect. 11, nn. 208-21, as cited by Jean-Pierre Torrell, Saint Thomas Aquinas Volume 2 Spiritual Master, p. 51, n. 69. Uncreated forms can only be properly and adequately understood by uncreated acts of understanding.

On the basis then of the embodiment which properly belongs to the character of incarnate human existence, given then what Aquinas says about human sensible experience and first and second operations of the human mind, Aquinas distinguishes between objects of sense and objects of intellect in a way which indicates that, for every element which exists in the cognitional order, a corresponding element can be posited in the ontological or metaphysical order. See Crowe, p. 212. While, for instance, the object of human sensible experience is an object as it exists in corporeal matter (presenting itself as a form as it exists in corporeal matter; Summa Theologiae, 1a, q. 85, a. 1: forma prout in materia corporali existit; [forma] prout est in tali materia), the object of human understanding is a form that has been grasped as a quiddity, essence, or “whatness” which exists in corporeal matter (cf. Summa Theologiae, 1a, q. 84, a. 7; Super I Sententiarum, d. 19, q. 5, a. 1, ad 7). In the context of inquiry, a sensible or material form, present in an image or phantasm, is first grasped by an act of sense, but it is grasped in a manner which then hopefully triggers an act of understanding that then apprehends the meaning of an intelligible form which specifies what something is. Cf. Sententia libri Ethicorum, 6, 9, 1239. Sensible form is to be distinguished from intelligible form. And then, thirdly, when a second operation of the mind begins to ask about the possible truth or reality of a given essence or form, in the reflective understanding which occurs in judgment, its term is the positing of existence or being: esse or actuality. Cf. Super I Sententiarum, d. 19, q. 5, a. 1, ad 7; De Veritate, q. 4, a. 2; q. 3, a. 2; q. 14, a. 1, pp. 208-9; Sententia super Metaphysicam, 6, 4, 1232. As Aquinas summarizes his thesis in the Super Boetium De Trinitate, q. 5, a. 3:


In a species of proportion which speaks about a correlation between the order of knowing and the order of being, acts of sense are correlated with potency (they reveal potency), acts of understanding with form (they reveal form), and acts of judgment with act (they reveal act or actuality).

However, as the ordering which exists within knowing also reveals a like ordering in the structure of reality, a mutual or reciprocal form of proportion can be specifically identified. It informs the species of proportionality which, in Aquinas, correlates every cognitional act with a corresponding metaphysical principle or element. In this specification, acts or elements within a set cannot be understood apart from each other and how each relates to the other. As every act of sense is ordered to first acts of understanding which, in turn, are ordered to second acts of understanding present in judgment, their metaphysical correlatives are also similarly ordered. Potency is ordered to form and form to act. Cf. Summa Theologiae, 1a, q. 54, a. 3. Everything which exists in material things exists as a composite of potency, form, and act and, conversely, every act of knowing is a composite of experiencing, understanding, and judging. Each act or element exists as it is because each is mutually ordered to all the other acts or elements. Citing some of Aquinas’s own words, “what is intrinsically ordered to something else ‘cannot be understood apart from that other’.” Cf. Super Boetium De Trinitate, q. 5, a. 3.

In turning then to how Aquinas goes on to speak about this ordering, in the Sententia super Metaphysicam, 9, 5, 1827-9, he notes that one discovers relations of mutual proportion among metaphysical principles through correlative relations of mutual proportion which also exist as differentiations within the structure and process of human cognition. The difference, for instance, between potency and act is illustrated and paralleled by the difference between sleeping and being awake. Capability or potentiality is distinguished from an act or operation which refers to a realized state of being. Since, cognitionally, for instance, the form of a material thing can only be understood (or apprehended) if it is detached from a material thing through an act of abstraction which functions by way of an interaction between sense and intellect, the form of a material thing (as a metaphysical principle) is understood as something which cannot exist apart from its union with matter (although the form of an immaterial thing can be understood apart from any union with matter). Cf. Summa Theologiae, 1a, q. 79, a. 7. An awareness of transitions in human cognition reveals a metaphysical principle which speaks about transitions that move from potency to act. Hence, by way of application in metaphysics, it can be said that potency stands to form as the organic body to the soul, the will to habitual righteousness, the possible intellect to habitual knowledge, the ears to hearing, and an eye to sight. Cf. De Potentia, q. 1, a. 1, Sententia super Metaphysicam, 9, 5, 1827-9; Lonergan, The Incarnate Word, p. 140, an unpublished manuscript translated 1989 by Charles C. Hefling, Jr. from the Latin of the De Verbo Incarnato. Form is act (first act) in relation to potency, but in relation to an act of being or operation (second act), it is a second species of potency. The first act of form is not to be confused with the second act of being or operation. By extension, in the relation which exists between form and act, it can be said that “as sight stands to actually seeing, [the faculty of] hearing to actually hearing, habitual knowledge to actually understanding, habitual righteousness to actually willing rightly, soul to actually living,…form stands to act.” Cf. Incarnate Word, p. 140. Through a reflection that is grounded in cognitive self-consciousness, metaphysical principles can be identified and all can be understood in terms of how they are all ordered to each other.

By way of conclusion then, Aquinas’s notion of proportionality derives from Aquinas’s experience of himself as a thinking, knowing subject. The subjectivity of his understanding is seen to participate in a wholly natural way in an objectivity that his understanding is naturally directed toward. No inherent, unbridgeable gap necessarily exists between the subjectivity, on the one hand, and objectivity, on the other. The subjectivity of a thinking, knowing being is joined to the objectivity of what can be known through a person’s subjectivity. The human spirit moves into objectivity through its self-transcending operations. Through our initial desires and aspirations, we are immediately joined to a world that is greater than ourselves. And then, by our activities which emerge as responses to what we want and desire, we can be joined ever more intimately to this same greater world which transcends our finite human existence. Within ourselves, unrestricted desires serve as a point of connection. In thinking about Aquinas’s notion of proportionality, we can rightly ask if Lonergan’s theory of isomorphism is essentially taken from Aquinas’s notion of proportionality. Is Lonergan’s theory genuinely Thomist?

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