Thomistic Gnoseology

Regarding Catholic philosophy there is a particular lack of knowledge, even within the Catholic population itself, so that accusations of idealism are generally accepted with heads bowed. It is true that Catholic philosophy is not materialistic—but it does not follow that it is the opposite, i.e., idealistic. This accusation is very old, and so is its refutation. But in a time when reading is not the common virtue, periodic reminders are necessary, in the face of a self-imposed amnesia. We say that the accusation is old because it goes back to thinkers like Holbach and Feuerbach (whose approaches had a critical echo in later scientific socialist thought, particularly in that of Engels and Marx), with their works, Christianity Unveiled (1766) and The Essence of Christianity (1841). And we also say that the refutation is old because it appears in the work of Ceferino González (1883), in La causa principal originaria (The Root Cause). And it is precisely because Catholic philosophy is neither idealistic nor materialistic, but realistic; and in the following sense:

“The philosophical realism of St. Thomas is first of all metaphysical; it starts from the being and reality of things. It has often been said that his conception of the real and of being dominates all of Thomistic metaphysics, and consequently all of his philosophy. Nothing is more accurate. And one might even add that it is the existence of an Aquinian philosophy itself that presents this notion as primordial. For at the basis of all reality and of every concept we find being as the ultimate and irreducible element. It is the last residue of all analysis—ontological, logical, psychological or moral. Being is the ultimate ontological foundation of all reality and the indestructible support of every concept” (Villafañé, 1974: 50).

And if there are still doubts about this, it is enough to review the encyclical Aeterni Patris of Pope Leo XIII, where Neo-Thomism, as Christian realism, is made the official philosophy of Catholicism:

“We exhort you, venerable brethren, in all earnestness to restore the golden wisdom of St. Thomas, and to spread it far and wide for the defense and beauty of the Catholic faith, for the good of society, and for the advantage of all the sciences” (Aeterni Patris, 1891).

On Thomism, in reference to the work and theological and philosophical legacy of St. Thomas Aquinas, it is known that one of his greatest works is the Summa Theologiae or Summa Theologicae, where Aquinas, in the words of Aspacia Petrou (2013), concentrates his efforts on building a synthesis between reason and faith, an attempt at mediation between the Christian conception of the universe and the human culture known to him. But what does this synthesis mean? A rationalization of faith? A fideization of reason? Not exactly; but an approach where faith is the volitional expression of a rational subject (i.e., which occurs in a framework of rationality and not irrationality, the latter attributed to non-human animals) that in order to gather knowledge needs to come into contact with the given natural reality that pre-exists him, through his senses, as a first step to a better understanding and comprehension of his surrounding reality, and of deeper issues.

It is worth mentioning that, during the time of St. Thomas, in the middle of the 12th century, Aristotelian thought was generating a great influence in the diversity of knowledge taught at medieval universities; and theology was not alien to this process, where the syllogism particularly gained relevance as a method of reasoning for scientific demonstration. It is in this sense that Aquinas’ Summa Theologicae incorporates Aristotelian logic into theological research, something that had already been previously suggested by the French theologian Peter Abelard and by Pope John XXI. Thus, Summa Theologicae becomes the highest expression of this process of rescuing the best of Classical thought for theological reflection; and this is how the fundamental structure of the contents of the Christian faith is consolidated in his work (Petrou, 2013:3); and within this, most particular is the interest of Aquinas in the intellectual faculties of the human being, in his Treatise on Man (Question 75 to Question 102).

The difference between a Thomist gnoseology and modern gnoseology should be specified. The difference lies in the fact that while the former is interested in how the human understanding operates in the perception of the reality of the natural world and of God, the latter is only interested in the first aspect, completely leaving aside the second, and relegating it to a mere space of criticism with the intention of discrediting it.

For Petrou (2013), Thomas Aquinas did not formulate a theory of knowledge in the sense that it would be known after Kant and thereafter, but undoubtedly, a systematization of reflections can be recognized in the Summa in this regard; and in that, whether a gnoseological justification of the feasibility of metaphysical knowledge, beyond the natural world that accesses the knowledge of God, is possible or not.

For Aquinas, following Petrou, these justifications are three in particular:

  1. The human mind does not possess a priori knowledge, in some sense. “The human understanding… is in potency with respect to the intelligible; and, at the beginning, it is like a tablet on which nothing is written” (ST, I, c.79.a.2: 723).
  2. Abstraction is the principal means that man has to make cognizable the essence of material things: “…agent understanding… by means of abstraction, makes intelligible the images received by the senses” (ST, I, c.84.a.7: 770).
  3. The knowledge of the essence of material things passes first through the sensible perception of these. That is, the senses provide the immediate data and are the source of knowledge in the present human condition: “For the operation of the sense, an alteration is required by which an intentional representation of the sensible form is established in the organ of sense” (ST, I, c.78 a.3: 716).

At this point, the foundations of a Thomistic gnoseology, in the part that is linked to justify the possibility of knowledge of spiritual objects, for authors such as Petrou (2013) and Copleston (2000), would be in principle endangered by the very foundations on which it is based, since if our knowledge begins and ends in sensible perception, is not the possibility of direct knowledge of immaterial substances, which are not, nor can they be, objects of the senses, annulled in this way? (2000: 381) This would also in principle nullify the capacity for metaphysical cognition (2013:5). Thus, the big question that presents itself to us is that if, spiritual objects cannot be appreciated by the senses, can human beings attain any objective knowledge of God?

In the sense-dimension of Aquinas, the human being, in his threshold of perception, is limited to the observation of physical objects; then the possibility of observation and, therefore, knowledge of spiritual objects is apparently annulled. Only in appearance, since the immediate refutation to this paradox is that, since the human being has a limited threshold of perception, the only way for him to become aware of spiritual objects is for the latter to be revealed to him at his threshold of perception. However, despite being a logical solution, it is at the same time naïve; a position that we share with the aforementioned authors, a reductio ad revelatio; and it is not the way in which Aquinas resolves the question.

As we have already mentioned, Aquinas rescued Aristotelian thought for his theological research; and it is within this framework that he integrated the doctrine of the hylemorphic composition of material substances, that all physical bodies possess matter and form (which in turn are created by God), into his theological theory. As well as the principle of individuation, where matter exists through form, i.e., when something takes form, it materializes and becomes cognizable, it is particularized. Aquinas limited the hylemorphic composition to material substances; he did not extend it to the incorporeal creation; that is, to angels, for example (Copleston, 2000: 322). He argued at this point that the form that makes possible the materialization of man in a body is the human soul (2013:7)—man being the material substance composed of soul and body. For Aquinas the human soul is the noblest of all forms because of its intellective nature; and for this reason, it has a faculty that transcends the mere plane of corporeal matter; and this is the faculty of understanding.

Now, at this point, Aquinas starts from an axiomatic premise, that the existence of the human soul is presumed, which in turn has been created by God (on the existence of God, Aquinas devotes question 2, articles 1, 2 and 3, in his Summa; for a view from natural theology, see my short essay on the work of Carl Sagan: “The Diversity of Science: A Personal View of the Search for God“). It is not the purpose this paper to compare the correlation between Thomism and neuroscience, which would be interesting to address in another work, without detriment to this; and in this regard, we will only say that, on the existence of the human soul, until some time ago the category of soul was rejected outright by modern psychology, psychiatry and neuroscience. However, this is beginning to change, since it depends on what we understand by “soul.” If by “soul” we understand a substance of a quasi-magical-etheric nature, then we are sure that there is no proof of its existence. On the other hand, if by “soul” we understand instead reference to the human mind itself (Giménez Amaya, 2010:163), then there is no doubt that this is an undeniable empirical reality.

Continuing with Aquinas, the faculty of understanding is what allows the human being the sensible abstraction necessary for the act of knowledge; and as a faculty different in each person, it is therefore the agent understanding—active, present—of each particular person; and it is this agent understanding that makes the spiritual objects intelligible in potency (they are not yet intelligible), and they become intelligible in action (they are in fact intelligible); and this is called illumination. Not an Augustinian illumination. The Thomistic illumination, unlike the Augustinian one (in reference to the gnoseology of St. Augustine), and which is crucial for the attainment of knowledge in Thomistic gnoseology, lies in the fact that God does not participate in the illumination of things; but that the active understanding present in man, and given to us by God, is the one that illuminates those things; that is, God has already given us the faculty for it, by endowing us with a soul with the faculty of understanding. And it is this active understanding that enables us to apprehend both particular (the corporeal objects of the natural world) and universal realities (and within these universal realities, the Universal in causando being the prototype of this universal category, God Himself and all the spiritual reality related); All this means that: “…human reason, even far from God and without the help of God, can apprehend the structure of the reality of the natural world; but not by virtue of reason itself in a materialistic sense, but by virtue of the human soul that God has placed in man. This is the central anthropological thesis from which the whole of Thomistic gnoseology is built; which, as can be seen, has metaphysical foundations” (Petrou, 2013:13).

As a colophon, and which would also be a topic for another section—what validity does the Thomistic theory of knowledge have, if it is confronted with contemporary neuroscience? At the very least, in the part concerning sensible perception as the first way of knowledge, we have an important correspondence, and in the following sense:

Do external sensible perceptions and, in general, sensible perception itself, objectify? Psychology and contemporary neuroscience tell us that they do. This objectification is, for example, the visual image that is formed at the end of the visual act, which can be very varied, depending on the circumstances, and can also be inadequate. The object (“what is seen”, “what is heard”, etc.) is a representative medium that refers in itself to the external thing in the case of external sensations. The same can be said of perception. We usually discern without problems between the objects of external perception and those of internal senses, such as imagination and memory, or between physically present objects and those that we capture through cognitive means external to our body, such as a mirror, a television set or the Internet; although we have to learn to make these discernments well; and sometimes we can deceive ourselves. The existence of objectivations in sensible knowledge is beyond doubt. We have already said that Aquinas has texts in which the sensitive species can be understood as the sensitive act itself in its content of intentio [information] (Sanguineti, 2011).

Israel Rene Lira is Member of the Peruvian Society of Philosophy and part of its Board of Directors as Secretary for the period 2020-2022 and is Deputy Director of the Center for Crisolist Studies and Head of its Department of Studies in Philosophy, Politics and Economy. He also serves as the Legal Advisor in Contracts with the State, Dispute Resolution and Arbitration Boards. He is a Columnist for the newspaper The Truth of Lambayeque, and has authored over 240 articles on philosophy, science and politics.

Featured: “The Trinity,” Rothschild Canticles, ca. 1300.