Descartes vs. Aquinas (and other scholastics) on the senses, the imagination, God, and the soul

In Summa theologiae, Ia, q. 75, a. 1, Aquinas writes:

[A]d inquirendum de natura animae, oportet praesupponere quod anima dicitur esse primum principium vitae in his quae apud nos vivunt animata enim viventia dicimus, res vero inanimatas vita carentes. Vita autem maxime manifestatur duplici opere, scilicet cognitionis et motus. Horum autem principium antiqui philosophi, imaginationem transcendere non valentes, aliquod corpus ponebant; sola corpora res esse dicentes, et quod non est corpus, nihil esse. Et secundum hoc, animam aliquod corpus esse dicebant.

In Discours de la méthode, AT, 37, Descartes writes:

Mais ce qui fait qu'il y en a plusieurs qui se persuadent qu'il y a de la difficulté à le connaître [i.e., God], et même aussi à connaître ce que c'est que leur âme, c'est qu'ils n'élèvent jamais leur esprit au delà des choses sensibles, et qu'ils sont tellement accoutumés à ne rien considérer qu'en l'imaginant, qui est une façon de penser particulière pour les choses matérielles, que tout ce qui n’est pas imaginable leur semble n'être pas intelligible.

But then, after seeming to express the same insight as Aquinas, Descartes goes on to suggest that people who accept the dictum according to which “n'y a rien dans l'entendement qui n'ait premièrement été dans le sens” (“nihil est in intellectu quod non sit prius in sensu”) have the same problem. Indeed, the dictum itself is an indicator of that problem!

Ce qui est assez manifeste de ce que même les philosophes tiennent pour maxime, dans les écoles, qu'il n'y a rien dans l'entendement qui n'ait premièrement été dans le sens, où toutefois il est certain que les idées de Dieu et de l'âme n'ont jamais été. Et il me semble que ceux qui veulent user de leur imagination, pour les comprendre, font tout de même que si, pour ouïr les sons, ou sentir les odeurs, ils se voulaient servir de leurs yeux : sinon qu'il y a encore cette différence, que le sens de la vue ne nous assure pas moins de la vérité de ses objets, que font ceux de l'odorat ou de l'ouïe; au lieu que ni notre imagination ni nos sens ne nous sauraient jamais assurer d'aucune chose, si notre entendement n'y intervient.

Descartes is either unaware of the scholastic explanation of the dictum (cf. e.g., De veritate, q. 2, a. 3, ad 19) or doesn’t accept it. My hunch is that it’s the latter. But not being an expert on Descartes, I would be glad for help on this.

How to Listen to Heretics (before burning them): How Today's Academy Might Aspire to be at least Medieval in Engaging the Other

Note: This development of a paper delivered to a Catholic Theological Society of America session on what today's academy might learn from Thomas Aquinas might be helpfully instructive for how we might listen to others who not only disagree with us, but who we believe teach or hold ideas that cause actual harm.


Heresy and Error: On Thomas’s Model of Really Listening to Others (Before Burning Them)

Robert Barry, Providence College Theology Department

            How might the academy today rise to the point where we might rightly and accurately be able to declare others heretics for what they teach or write? The possibility of a properly theological declaration of a teaching as heretical, and the one holding that teaching as a heretic deserving of exclusion from the academy, was a distinctively medieval achievement. A common understanding of the sources and the method of theological reasoning permitted the demonstration of a position as erroneous. This process of demonstrating the errors of one’s opponent by reasoned arguments drawn from commonly held principles is vividly evidentin Thomas Aquinas's Summa Contra Gentiles: Thomas engages the arguments of Photinians, Sabellians, Arians, Nestorians, Manicheans and more regarding the doctrines of the trinity and the incarnation. Thomas grounds his engagement with heretical teachings in a reasoned analysisof the source admitted by both himself and his opponents: the canonical scriptures. where he demonstrates the errors of heretics concerning the divinity of the Son of God. I will then consider how the theological academy might take instruction from this procedure in engaging the other today, when that "otherness" is constituted by an opposition of theological conclusions.


            Thomas divides his Summa Contra Gentiles into four books, and in each engages the arguments advanced on behalf of different possibilities for the subject at hand. The books differ, however, in method. The first three treat, in turn, God, Creation, and Providence as such things might be known through unaided reason. Book IV recapitulates this investigation of God, Creation and Providence, but now by reference to what is known through divine revelation. Thus this book takes up in turn God as Trinity, God's assumption of a created human nature in the Incarnation, and Divine Providence as ordering humans to a friendship with God manifested in Eternal Life.

            The arguments of the first three books are intended to persuade interlocutors of any stripe, as they assume nothing but what can be known through the power of reason common to all who might hear those arguments. This approach is properly regarded as a philosophical argument, treating theological topics but not grounding them on properly theological principles. Opposition to the conclusions demonstrated in these first three books is not evidence of lack of faith on the part of one's interlocutor; the argument begins in fact with the presumption that the other lacks the faith by which he or she would assent to revealed truths. One's conversation partner may be mistaken, obtuse or simply stupid, but would not properly be called a heretic.

            By contrast, Book IV of Thomas’s Summa Contra Gentiles is explicitly theological, and aims to engage those who would affirm the starting points proper to theology, namely, divinely revealed truth. In addressing the topics of the Trinity, the Incarnation and Eternal Life, Thomas sets forth the arguments of the heretics who deny the orthodox teachings on these questions, and then demonstrates the inadequacy of those arguments as the reason for rejecting those heretical and erroneous conclusions.

            First, a clarification on some technical use of terms. As with virtually everything else a scholastic theologian might address, Thomas categorizes the others with whom he engages in debate based on the degrees and principles by which they differ from him. Someone who is simply “other” in an absolute sense shares nothing in common with a speaker, and offers no point on which a conversation might pivot. But for Thomas, nobody truly falls into the category of being absolutely other; one will find basic principles that are self evident and operative in any exercise of reasoning or judgment, whether the other interlocutor adverts to them or not.

            Beyond those basic common operative principles, you may find commonly shared understandings or convictions upon which discussion and argument might proceed. Sometimes those points arise from the exercise of reason or from experience; in those cases, a discussion would proceed along philosophical lines, relying only on what a healthy use of reason can ascertain. Other times, those points arise from a common assent to revealed truth. Such assent can be partial, as when some texts are commonly accepted by two interlocutors as authoritative and revealed (as is the case between Christians and Jews with respect to the Torah).

            Other times, two parties in a conversation can agree about the totality of sources as authoritative, but differ in the understanding that emerges through argument from those sources. It is only in this last situation that a medieval scholastic theologian such as Thomas would properly speak of theological error and heresy. This is precisely the approach that Thomas takes in Summa Contra Gentiles IV, for there he seeks to set forth the argument of the “other” and engage it in terms of sources that those “others” would recognize as authoritative. He does this consciously, as is evident in editorial comments where he adverts to the sincerity of the reasoning of the opponents, but categorizes such reasoning as heretical or erroneous nonetheless.

            Thomas begins his engagement with Trinitarian heresies in Book IV by outlining the evidence for the divinity of the Son of God as articulated in scripture. The examples of this are legion, so Thomas presents a sample of where Jesus refers to himself, or is referred to by others, as the Son of the Father, where the Father clearly indicates "God": thus he cites the opening of Mark's gospel, which declares "The beginning of the gospel of Jesus Christ, the Son of God," passages from John: "The Father loveth the Son and He hath raiseth up the dead, and giveth life to whom He will."(Jn 5:21), and Paul's letters, including a passage from Hebrews: "God who, at sundry times and in divers manners, spoke in times past to the fathers by the prophets, last of all in these days hath spoken to us by His Son."(Heb 1:1). Though Thomas admits it is not as common to find, he points to passages from the Old Testament that speak directly of the Son of God, such as Proverbs: "What is His name, and what is the name of His Son, if thou knowest?"(Prov 30:4)

            These citations are not cited as proof texts, but rather stand as placeholders for the full evidence to which he will refer as his argument progresses. The significance for his argument is that testimony to the title "Son of God" is not an isolated or rare bit of evidence, but rather something found widely in both testaments, with universal attestation by all authors of the New Testament. This establishes that, at the very least, there is one who is properly titled and proclaimed "The Son of God," and in light of the authority of the New Testament, Jesus is that same Son of God.

            Medieval authors were not without standard exegetical rules by which ambiguities and nuances in the texts might be clarified. Thus Thomas recognizes that the scriptures employ the term "Son of God" to refer to any number of individuals or groups, especially in the Old Testament where the kings of Israel, namely David and Solomon, are proclaimed the Lord's Son. The training in grammar and rhetoric that served as the prerequisite for the higher study of theology in universities and in houses of study would then be drawn upon to distinguish differences in predicating the title of "Son of God" of particular individuals. The fuller context of the passages cited earlier as authorities in the Old Testament as incipient declarations of God's Son show that such passages do not employ the title in the same sense as employed for human subjects. Thus, to the Psalm which declares "The Lord hath said to me: Thou art My Son," a declaration that might refer to David, cannot be rightly understood as referring to David when it continues "This day I have begotten Thee." and "I will give The the Gentiles for Thy inheritance, and the utmost parts of the earth for Thy possession."(Ps 2:7-8) The fact that things are predicated of the Son of God in passages like this Psalm, but not properly of David or Solomon (neither of whom received the gentiles for their inheritance or came to possess the utmost parts of the earth), indicates that neither of these men are properly the one proclaimed here as the Son of God. What is stated here obliquely, that there is one who is properly the Son of God, foreshadowed by kings who are only called the "Son of God" in a qualified sense, is fully stated clearly and directly in the testimony of the New Testament authors.

            That God is capable of generation is evident from all the passages which speak of creation as a product or generation of God. Yet that the scriptures are speaking of a distinctive generativity of God, underlying the generation of created being, but referring more properly to a divine generation of God from God, is evident from the passages which speak directly of the Son of God as divine. Thus in addition to the passages Thomas cites which speak of that general property of generativity, he cites the straightforward and direct statement at the beginning of John's gospel: "Therefore, lest nothing more be understood by the words for "paternity," "sonship," and "generation" than the efficacy of creation, the authority of Scripture added something: When it was naming Him "Son" and "begotten", it was not silent about His being God, so that the generation mentioned might be understood as something more than creation." (SCG IV, Ch. 3 [1]) Thus while it is possible to regard passages about a Son of God and God "begetting" as referring to merely created realities, such created realities allegorically point to a reality that is only known by divine revelation. Thus Thomas concludes "Thus, then, are we taught from sacred Scripture that the Son of God, begotten of God, is God."

            In the next part of Book IV, Thomas addresses the Photinian, Sabellian and Arian opinions that are contrary to the above conclusion. In each case, Thomas identifies the biblical sources adduced by the heretics in their argument, concluding that Christ either is not the Son of God in any unique sense (the Photinians), nor begotten of God (the Sabellians), or truly God (the Arians). In each case, the position advanced by the heretic is partially true, but takes that partial truth as the touchstone in light of which other passages are subsequently ignored or willfully misread.

            Thus the Photinians take scripture's habit of"calling those who are justified by divine grace "sons of God"(SCG IV, Ch. 4 [2]) and interpret statements of Christ as the Son of God in that same sense. Thomas then develops that Photinian position further, even, by citing the reasons why it would seem appropriate to presume Christ to be the Son of God in that same sense: citing Christ's statement "All power is given to Me in heaven and in earth" (Mt 28:18), Thomas argues that if Christ was indeed the eternal Son of God, sharing in the divine nature without beginning or end, then it would make no sense for Christ to say that power was given to him in time. Likewise, statements that speak of Christ as "made" and as "predestined" seem contrary to the orthodox conclusion about the divinity of Christ. By these and other reasonings, Thomas argues to demonstrate the conclusion held by Photinians: "that by merit Christ acquired divine honor through grace and that He was not by nature divine." (SCG IV, Ch. 4 [9])

            Thomas addresses the conclusion of the Sabellians and the Arians in the same manner: he presents the arguments that are advanced on behalf of their positions, demonstrating how their conclusions follow from the starting points upon which they all can agree. But he then proceeds to show how that same body of evidence necessarily leads to conclusions contrary to the Sabellian and Arian positions, demonstrating an incoherence in the total positions of these thinkers.

            The arguments of the Arians command the most extended treatment by Thomas, who devotes the entirety ofChapter Six to explicating precisely how the Arian conclusion that Christ was a creature might be seen as following from a wide range of truths revealed in the New Testament and in the Old Testament. Thomas adds the insight that this conclusion seems to have arisen from the influence of Neoplatonic philosophy, through whose lens the passages cited would seem to give evidence for the Son of God as just such a preeminent creature.

            Thomas continues in Chapter Seven with an exposition of specific scripture texts that the Arians cannot intelligibly accept without contradicting their claim that the Son of God is a creature; this exposition presents overwhelming evidence, from the Old Testament and the New, that both directly and indirectly, in both what is done by the Son of God, and said by the Son of God, and said about the Son of God, that the Son is not a creature, but indeed is divine in the same sense that God the Father is divine. Since, however, as Thomas says "Truth cannot be truth's contrary,"(SCG IV, Ch. 8 [1]) it is not sufficient for Thomas to demonstrate simply that another position can be drawn from the scriptures, but rather, he dedicates Chapter Eight to an exposition of how the passages relied upon for concluding to the Arian position themselves cannot rightly be read in the sense that the Arians would take them.

            Thomas's response to the erroneous conclusions held by the Photinian, Sabellian and Arian heretics is a properly theological one: Thomas responds, not by merely citing the credal conclusions enunciated earlier, but rather by turning to the same sources recognized by all parties involved, namely sacred scripture, and demonstrating by reasoned argument both that the positions these others hold are incoherent in light of the totality of the scriptures they admit as authoritative, and that the particular passages upon which their positions depend are wrongly interpreted. For Thomas, these heretical positions are primarily the product of badly done theology. Theology that is done badly may arrive at some true conclusions; so, for example, the Arians and Photinians both rightly recognize over against Sabellius that the Son is begotten, and is not the Father, while the Sabellians rightly recognize the true divinity of the Son. But such positions, in toto, are simply erroneous.


            The strategy employed by Thomas in the Summa Contra Gentiles has parallels in the juridical procedures by which universities responded to masters or students who publicly wrote or taught erroneous positions.[1] The procedures clearly designated different categories by which a theologian might deviate from the truth of the faith: a theologian's teaching might be clearly erroneous, and directly contrary to the rule of faith, or his teaching might be found to be true, when interpreted rightly, but might just "sound bad" as they are stated. The judgment rendered, however, was about the truthfulness of the teaching that was written or spoken; it was a separate matter to determine the quality of the will of the one who had written or spoken the suspect teaching.

            In most cases, when those charged with rendering a finding did in fact determine some teaching to be erroneous or misleading, students or masters responded in humility, renouncing the error into which they had knowingly or unknowingly fallen and correcting their writing or subsequent teaching. Given the paucity of evidence for dramatic trials for heresy, it would seem that most correction was done informally, and proceeded without much public drama at all. Only when a scholar was shown evidence of the error of his teaching, and refused to adhere to the steps outlined as necessary steps for correction, would the scholar himself be regarded as a heretic, willfully and pertinaciously holding a teaching that had been duly declared heretical. Whatever subsequent civil penalties might accrue from the determination of heresy, the academic penalty was clear: one who taught error, and who did so with an irreformable and evil will, was to be excluded from the life of the academy. It might be worth noting that the notable cases and highly public cases of heretics burnt at the stake were not academic exercises, but primarily political: Jan Hus, Joan of Arc, Girolamo Savonarola and Giordano Bruno are perhaps best seen as (sometimes personally difficult) individuals who were caught up in the political dynamics of violence of their era, rather than as extreme examples of academic censure.

            Notably, these procedures were academic, and presumed that the scholar under investigation had not erred maliciously, but would respond to fraternal correction. Thus the rare instances where we have record for a final declaration of a scholar as a heretic were dramatic, and rare, precisely because the bar for such a declaration was so high: one needed to have demonstrated to the accused that what he publicly wrote or taught was indeed clearly erroneous, and the accused would have to have refused to reject that error. The failing of a heretic, then, was not merely an academic one, but a spiritual one; some deeper vice, whether that of pride or curiositas, occluded the heretic from having genuine faith, and led them to teach error consistently and knowingly in substitution for the true faith. Such a scholar was thus judged to be a danger, both to himself and to the academy, and was justly excluded from the life of the academy.


            What, then, might we learn from the example of the medieval academy, and from the approach of Thomas Aquinas in Summa Contra Gentiles, Book IV? It might seem rather insane to suggest we reintroduce the procedures for heresy trials into the modern academy; and I would agree. Yet a procedure that is capable of judging the theological merits of an academic’s work according to commonly recognized sources, principles and methods, as Thomas’s arguments do and as heresy proceedings should, would be far more preferable to the current procedures by which the theological academy includes or excludes scholars in its activity of study, teaching and writing, where the criteria for such inclusion or exclusion is sometimes far more arbitrary and decidedly untheological than the medieval practices themselves.

            The absence of heresy tribunals does not mean the academy employs no fora for rendering judgment on the suitability of a particular scholar for inclusion in the academy: from admissions committees to thesis committees, from hiring committees to tenure committees, from editorial boards to elections for boards of professional organizations, judgment is rendered regularly on the writings and teachings of theologians today. Yet any agreement among theologians about theological method today is severely limited, shared by specific subgroups or schools working bodies within academic theological societies, but hardly by the entire society itself, never mind shared by all the academic societies in toto.

            In the absence of broad agreement on the standards of what constitutes good or bad theology, decisions about the suitability of a theologian or a school of thought are necessarily made in such fora. The danger is that an essential distinction operative in the medieval procedures concerning heresy, and evident in Thomas’s engagement with heresies in his Summa Contra Gentiles Book IV, will be overlooked, and two distinct issues may be conflated. If academic theology fails to maintain the medieval distinction between judging whether the scholar’s teaching was erroneous, and determining whether that scholar would remain pertinacious in holding that error once it was pointed out, then to hold a position perceived as erroneous (from one’s perspective) is taken as evidence of a bad will itself in the one who holds such positions. Dialog and debate are then naturally replaced by the demonization of one’s opponents and the struggle to seize the power by which such demons may be exorcised from the respectable places in the academy. In the absence of common standards, the diversity of schools of thought that might be found in the middle ages (which consisted of differences within the common practice of academic theology) devolves in our age into a multiplicity of camps, staking claims to territory and defending them by whatever means are necessary. Without recourse to common criteria for good and bad theology, we find a perverse inversion of the procedure for medieval trials for heresy: one's opponent from a different camp has an evil will, and it is that evil will that results in his teaching a position opposed to one's own.

            Medieval charges of heresy, or even rightly of error, depend on the activities being common; in the academy today, I am afraid, the activities of the theologians assembled in the various gatherings of academic societies of theology today are merely diverse, and in the absence of the capacity for judgment of the truth of the teaching of those others, judgment is rendered on the person him or herself. Without common method or sources, we are not even at the point of understanding what other speakers or writers are trying to do, never mind being able to evaluate whether they are doing it well, and certainly not at the point of genuinely determining whether they are doing it with a good will or a genuine faith.

            In this respect, our academy is in the state of simply being "others" to one another, not capable of rightly understanding, judging or evaluating what the other is doing. In this respect, we are not up to the task of the reasoned engagement we see Thomas working at in Book IV of the Summa Contra Gentiles; I fear, we are not even operating at the level of engagement that marks the first three books. We are short of even understanding what dialog might be, or what it might mean, never mind being able to adequately engage in it. In this respect, the academy has devolved from the scholastic model by which universities engaged in cumulative and progressive activities, and returned to something more akin to the situation of theological camps operating from separated monastic schools, consisting of a small cadre of listeners under the tutelage of single masters whose activities and teachings make good sense to a small intended audience, but not to anyone else outside the abbey walls. In such a frame, the absence of charges of error and heresy would not be an achievement of unity and coherence, but rather a sign of its opposite.


     [1]  Here I am indebted to J.M.M.H. Thijssen, Censure and Heresy at the University of Paris, 1200-1400. Philadelphia: University of Pennsylvania Press, 1998.

Nazianzus: Possible to Conceive the Essence First, then the Persons

In a recent article, I critiqued certain iterations of the "Social Analogy" and what I call the "I - Thou" argument for the Trinity. 

In the course of the argument, I noted my agreement with Bruce Marshall (see his fine essay on the Trinity in The Thomist, 2010) that, even in the East, theological reflection sometimes begins with the one essence and subsequently adverts to the distinction of persons. Prof. Marshall adduced some evidence; I adduced some evidence. I would point to another text in G. Nazianzus, from the commonly available English translations: "When we look at the Godhead, or the First Cause, or the Monarchia, that which we conceive is One; but when we look at the Persons in Whom the Godhead dwells, and at Those who timelessly and with equal glory have their being from the First Cause--there are Three Whom we worship." (Theological Oration on the Holy Spirit, par. 14). I take this statement as indicative of the macro-structure of the Theological Orations.

Happy feast of St. Thomas Aquinas again!

January 28 is Aquinas’s liturgical feast according to the calendar of Paul VI. On that date in 1369 Aquinas’s relics were translated to the Dominican church in Toulouse.

March 7 is Aquinas's liturgical feast according to the pre-Pauline calendar of the Roman Rite. Aquinas died on that date in 1274 at the abbey of Fossanova, where he had stopped after taking ill on his way with Reginald of Piperno to the second Council of Lyons.

Both calendars are still in force in the Roman Rite.