Aertsen, Jan A. 1984. Medieval Reflections on Truth. Adaequatio Rei Et Intellectus. Amsterdam: VU Boekhandel.
Inaugural address on the occasion of his taking up the chair of Medieval philosophy of the Free University in Amsterdam on November 9, 1984.
"There are certain basic words which form the undertone of our thinking and of the manner in which we experience things. These basic words are not unchangeable; they often receive a
different content . . . One such basic word is 'truth'."
This is the start of the report of the Synod of the Reformed Churches in the Netherlands, issued in 1981, "On the nature of the authority of Scripture".(1) How does it happen that
the Bible is read so differently? In searching for an answer to this problem, the report adopts a course remarkable within the. Reformed tradition. It poses a truly philosophical question: "What is
truth?" That the Bible is read differently is related to the fact that not all people mean the same by what they call "truth".
If I want to raise this same question today, then I am in good company - though I must add at once that it is the matter rather than the company that motivates me. From the outset,
that is, as early as with the Greeks, philosophy and truth are seen in an intimate connection. Aristotle, for example, describes philosophy as the "theory" of truth.(2) It is in the Middle Ages,
however, that for the first time treatises appear under the title of De veritate, where truth itself is explicitly made the object of reflection. I would like to draw your attention to
medieval observations on the query about truth.
'Adaequatio rei et intellectus' as the medieval formula of truth and the criticism of it.
Is an exposition on this theme worthwhile, though? Do we not already know what truth was in the Middle Ages? Probably there is no formulation in scholastic thought that has become
more widely known. Even those who did not enjoy the privilege of a classical education are able to say that truth is adaequatio rei et intellectus. What is meant by that seems to be clear.
The formula appears to express the "natural" idea of truth, i.e., the correspondence between thought and reality. The determination of truth as adaequatio has become so self-evident that, as
the Handbuch philosophischer Grundbegriffe states, it is the point of depart and reference for all contemporary discussions on truth.(3) It can be added that this occurs mostly in a critical
sense. Two examples may suffice.
In the above-mentioned synodal report the first chapter sketches the changes in the concept of truth over the course of time. The so-called subject/object relation underlies the
entire exposition, apparently from the unquestioning presupposition that this relation is fundamental to the phenomenon of truth as such. The changes in the concept of truth, then, are described in
three phases. Successively the report speaks of "objective truth", "subjective truth" (in systems of thought like idealism and existentialism), and finally, of a newer conception called the
"relational" concept of truth - the objective and the subjective in one. This means that "truth always occurs within a relation, within the 'relatedness' of man to something else."(4) As the report
claims, moreover, this relational concept of truth links up with what the Bible calls truth.
The objective concept of truth - the most current idea of truth - is represented by the medieval formula, phrased "truth is the correspondence of the human way of picturing things
with the matters themselves." The human way of imagining things, the human consciousness, is like a mirror able to reflect "the objective state of affairs". This conception of truth is not only
ascribed to Thomas Aquinas, but to a great variety of people: " . . . Greek philosophers, . . . the classical Reformed theologians, . . . the logician Bertrand Russell, . . . the Marxist Lenin". The
drawback of this conception, in the assessment of the report, is that man is very passive. Does knowing the truth not demand man's activity, research; and wrestling? Without a human spirit there is
An entirely different criticism can be found in Heidegger, who dealt most thoroughly with the western conception of truth. The lectures he delivered at the University of Freiburg
during the winter semester of 1942-43 appeared in 1982 in the Gesamtausgabe of his works under the title Parmenides.(5) Strictly speaking, the title is misleading for actually these
lectures deal with the essence of truth, the identical subject that engaged Heidegger in writing Vom Wesen der Wahrheit, which dates from the same time. In the lectures, however, there is "a
more direct confrontation with the history of western thought".(6) In his view a change in the essence and "locus" of truth has evolved in philosophy. Truth becomes "rightness" (Richtigkeit)
of knowing and asserting; it is no longer "unconcealedness" (aletheia) of being, as it was for the early Greek thinkers. The medieval formulation fixes this essential transformation. "
`Veritas est adaequatio intellectus ad rem' Im Sinne dieser Umgrenzung des Wesens der Wahrheit als Richtigkeit denkt das gesamte abendländische Denken von Platon bis zu Nietzsche. "(7) Truth
becomes a characteristic of a mental act within man. Inevitably the problem then arises how a psychical process in the inner man can be brought into agreement with things outside.(8) This traditional
and current conception of truth, however, is derivative (abkünftig). Parmenides' thought reveals "the road of truth, far away from the beaten track of men". (Fragm. B 1, 27). It can
give us a reminder of the forgotten "primordial" sense of truth, the unhiddenness of being, which is the ground of the possibility of rightness.
But when the proper function of philosophy is to "re-mind", we are also allowed to ask of this twofold criticism: do we recall the meaning of truth as adaequatio rei et
intellectus at all? Does it have a merely derivative sense, i.e., the rightness of thought? On the other hand, does the formula imply that truth is "reflection" and leave the human mind out of
account? These questions lead, me this afternoon to focus on medieval views of truth, in which the idea of the adaequatio plays a central role." (pp. 3-5)
Looking back over the course of this discussion, we may conclude that the criticism of the medieval adaequatio-formula, outlined at the beginning, did not grasp its
original meaning. Neither is this conception concerned with truth in a merely derivative sense, nor does it ignore man's activity. For in the previous analysis we observed that Thomas's notion of
true includes first, transcendentality, second, relationality, third, anthropocentrism, fourth, the fulfilment in an act of the intellect, fifth, the necessity of a norm and measure, sixth the
intrinsic connection with the word, seventh, the relation to the divine Logos, and finally, the identity with God Himself. These moments are implicitly or explicitly expressed in the formula
adaequatio rei et intellectus, in which every term is charged with meaning.
Compared to the breadth of this conception, modern theories appear to be a reduction of the integral process of truth. It is philosophically important to note that in the medieval
approach what is fundamental to truth is not the duality of subjective and objective from which then their togetherness has to be conceived. Rather, it is the primordial conformity of being and
intellect that is fundamental to truth. Indeed, as we have seen, being and thinking are the same in the Origin.
Another remarkable aspect in this medieval view is the attempt to integrate philosophical and religious truth. This endeavour runs parallel to the philosophical introduction of the
synodal report of the Reformed Churches, with which I began this address. Its intention is that the "relational" concept of truth links up with what the Bible calls truth. Thomas's conception lies
concretely in the notion of word, a good example of the way in which his understanding of truth is deepened by a theological reflection. But that which fundamentally enables the integration is the
basic idea of the transcendentality of truth. This conception underlies his entire discussion.
The medieval doctrine of the transcendentals - being, one, true, good, and beautiful - forms "the heart of scholastic ontology and metaphysics."(93) This doctrine will be the
subject of my research over the coming years. Today I wanted to present you with a sample of it.(94)
(1) In the Dutch original, the report carries the title God met ons . . . over de aard van het Schriftgezag, published in: Kerkinformatie, nr. 113 (Febr. 1981). The report
was translated into English by the Secretariat of the Reformed Ecumenical Synod, Grand Rapids, Mich., U.S.A.
(2) Metaphysica II, c. I, 993 a 30. Cf. 993 b 20.
(3) L.B. Puntel - Wahrheit, in: Handbuch philosophischer Grundbegriffe III, München, 1974, 1651. Cf. Th. de Boer - De eindigheid van de mens en de oneindigheid van de
waarheid. De geschiedenis van het fenomenologisch waarheidsbegrip van Brentano tot Levinas, in: De eindige mens?, Bilthoven, 1975, 55 f.
(4) o.c., 10 (in the English translation).
(5) Frankfurt am Main, 1982 (Gesamtausgabe II. Abteilung, Bd. 54).
(6) Vom Wesen der Wahrheit, in: Wegmarken, Frankfurt am Main, 1967, 73-97. See also for Heidegger's view of truth Sein und Zeit, VIII ed., 1957, 212 f.; Vom Wesen
des Grundes, in: Wegmarken, 25 f.; Platons Lehre von der Wahrheit, in: id., 109-144; Kant und das Problem der Metaphysik, Frankfurt am Main, III ed., 1965, 31 f.; 107 f.;
Cf. W. Brettschneider - Sein und Wahrheit. Über die Zusammengehörzgkeit von Sein und Wahrheit im Denken Martin Heideggers, Meisenheim, 1965; J. van der Hoeven - Heidegger,
Descartes, Luther, in: Reflecties, Opstellen voor Prof. dr. J.P.A. Mekkes, Amsterdam, 1968, 71-116; Th. de Boer - o.c., 78 f.; E. Tugendhat - Heideggers Idee von Wahrheit, in: G.
Skirbekk (Hrsg.) - Wahrheitstheorien. Eine Auswahl aus den Diskussionen fiber Wahrheit im 20. Jahrhundert, Frankfurt am Main, 2nd edition, 1980, 431-448.
(7) Parmenides, 73.
(8) id., 74.
(93) J.B. Lotz - Zur Konstitution der transzendentalen Bestimmungen des Sein nach Tomas von Aquin, in: Die Metaphysik im Mittelalter (Hrsg. P. Wilpert), Berlin, 1963,
(Miscellanea Mediaevalia Bd. 2) 334.
(94) Cf. my essay "The Convertibility of Being and Good in St. Thomas Aquinas" to be published in The New Scholasticism [59, 1985, pp. 449-470]
———. 1988. Nature and Creature. Thomas Aquinas's Way of Thought. Leiden: Brill.
Translated by Herbert Donald Morton from the Dutch Dissertation Natura en Creatura. De denkweg van Thomas van Aquino (Amsterdam, 1982) .
Contents: List of Abbreviations XI; Preface XIII; Introduction 1; 1. From questioning towards knowing 7; 2. By the way of predication (Per via predicationis): Definition
and participation 54; 3. By the way of causality (Per viam causalitatis) 92; 4. The way of truth (Via veritatis); 5. By the way of reason (Per viam rationis) 191; 6.
Hodo-logy 230; 7. Principium 279; 8. Finis 337; Epilogue 391; Bibliography 397; Index Rerum 409-413.
"The study presented here is the revised version of a doctoral dissertation that was submitted to the Central Interfaculty (Faculty of Philosophy) of the Free University in
Amsterdam in fulfillment of the requirements of the Doctorate of Philosophy and defended publicly on April 16, 1982. That this dissertation was originally published at a Protestant university may be
considered a sign of common responsibility for a Doctor of the still undivided western Christendom." (from the Preface).
"Our aim was to develop an interpretation of the inner coherence and direction of Thomas's philosophizing. This objective was pursued by following his way of thought and by seeking
to fathom the motives of his quest for intelligibility. Now that this inquiry has been brought to an end, it turns out that our investigation of Thomas's way of thought has proceeded according to the
order of the transcendentals "being," "true," and "good." Their logical order, which Thomas sketches, is that "being" is the first and that "the true" and "good" come after it, in this order. For, so
he argues in S. Th. I, 16, 4, "knowledge naturally precedes the appetite." "Being" is the first, "good" the ultimate.
From the triad "being"-"true"-" good," their convertibility, and their conceptual nonidentity a number of coherences can be brought to light that were not always signalized or
worked out by Thomas himself. They are nonetheless most illuminating for the movement of Thomas's thought, and also for the course of our investigation. These coherences show that in what has
preceded, a multiplicity of themes has been traversed according to a definite pattern." (p. 391)
(7) The result of Aristotle's exposition in Metaph. II is the thesis: "There is the same disposition of things in being and in truth" (4.3.1.). On the analogy of this
thesis Thomas himself frames the statement: "There is the same disposition of things in goodness and in being" (8.1.1.). A hierarchical order can be found in being, the true, and good. Whatever is in
any way and is true and is good is to be reduced to the first Being, to the maximally True and to the ultimate Good, namely, God. The causal relation of God to the world is therefore threefold. He is
'causa efficiens', 'exemplaris', and 'finalis'. With this threefold causality Thomas connects the triad of transcendental determinations 'ens (or: unum) - verum - bonum'.
This coherence of the transcendentals with the divine causality makes clear that the "anthropocentrism" in Thomas's doctrine is to be specified: man is marked by a transcendental
openness, certainly, is "in a certain sense all things," but not in a constitutive sense. It is typical of the medieval approach to inquire into the origin of being, into the ground of the truth and
goodness of things. This origin and ground is conceived as "creation." Every being is true and good because it is thought and willed by the Creator. The relational character of the transcendentals
"true" and "good" is ultimately founded in the relation to the divine intellect and will.
The divine foundation of the transcendentals is connected by Thomas with the circulation in God Himself, the eternal coming forth of the Persons. "Being" (or: "one") is attributed
by appropriation to the Father, "true" to the Son, and "good" to the Spirit. This connection with the divine Trinity provides the basis for developing a trinitarian interpretation of that which is
creaturely. In the conceptual nonidentity of the transcendentals 'ens - verum - bonum' the threefold structure of that which is comes to expression. Viewed in the light of the Triune
causality, the different components of that which is concur into a unity.
"Being," "true," and "good" are not only common names but also divine names. The relation of what is common to what is proper to the Transcendent is conceived by Thomas in terms of
"participation." He subscribes to Aristotle's criticism of this Platonic idea by stating that there
are no separate, self-subsisting Forms of natural things. But Thomas, in the prologue to his commentary to pseudo-Dionysius's De divinis nominibus, recognizes the
legitimacy of this doctrine with regard to what is most common. Only in the case of transcendental forms can a first be posited which is the perfection essentially and as such subsistent. All else
must consequently be understood as participation in this perfection. Against this background it becomes understandable that Thomas conceives "creation" preeminently as "participation."
The doctrine of the transcendentals is found to have an important, integrating function in Thomas's way of thought. In man's quest for intelligibility, the transcendentals present a
comprehensive perspective on nature and creature. Their circular ways come to an end in the return to the Origin, in which "being," "true," and "good" are perfectly one." (pp. 395-396).
———. 1996. Medieval Philosophy and the Transcendentals. The Case of Thomas Aquinas. Leiden: Brill.
Contents: Preface IX-X; Introduction 1; One. The Beginnings of the Doctrine of the Transcendentals 25: Two. Thomas's General Account of the Transcendentals 71; Three. Metaphysics
and the Transcendentals 113; Four. Being as the first Transcendental 159; Five. One as Transcendental 201; Six. True as Transcendental 243; Seven. Good as Transcendental 290; Eight. Beauty: A
forgotten Transcendental? 335; Nine. Transcendentals and the Divine 360; Conclusions 416; Bibliography 439; Index Nominum 455; Index Rerum 459-467.
"The title of this book speaks of "Medieval Philosophy" and "the Transcendentals." It can be read as affirming that there is a philosophy in the Middle Ages and that this philosophy
encompasses a doctrine of the transcendentals alongside many others.
But our aims in this work are more ambitious. Our title means to suggest a more intrinsic relation between the terms "Philosophy" and "Transcendentals" than mere juxtaposition. We
want to show that philosophy in the Middle Ages expresses itself as a way of thought which can be called "transcendental." The present book may therefore be seen as a contribution to the discussion
of the question: what is philosophy in the Middle Ages? A recent review of literature offers a telling example of the relevance of this question: "Unmistakably philosophical research about the Middle
Ages has fallen into a crisis ( ... ) It is even impossible to reach agreement on the premise what philosophy means in the Middle Ages.(1) '"
(1) A. Speer and J.H.J. Schneider, "Das Mittelalter im Spiegel neuerer Literatur", in: Theologische Quartalschrift 172 (1992), p. 235.
In this introductory chapter I want first to analyze three different answers to the question "Is there a medieval philosophy?" that are (or were) important for the place of the
Middle Ages in the history of philosophy. This analysis affords me an opportunity to take stock of the current study of medieval philosophy (0.1.-0.3.), I will then explain how I myself approach the
period, indicating what, in my view, is constitutive for the thought of the Medium Aevum (0.4.). This final section will clarify the intention of this book." (pp. 1-2).
"Is there a medieval philosophy? Thus far I have discussed three significant conceptions, those of Gilson, of the Cambridge History and of De Libera. They have made substantial
contributions to the study of medieval philosophy, but I have formulated objections to all three because they do not provide sufficient insight into the philosophical dimension of medieval thought.
Now in order t0 make some progress in this question, I am interested in statements by medieval writers in which they personally indicate what they consider to be fundamental to their thought or what
they regard as decisive for the possibility of philosophy. Such "ego" statements are relatively rare among Scholastic authors, but they are not altogether absent. I mention four examples, all taken
from theologi. [The authors discussed are Bonaventure, Thomas Aquinas, Duns Scotus and Meister Eckhart.] (p. 17).
"The transcendental way of thought is neglected in the conceptions of medieval philosophy discussed above. Although the doctrine of the transcendentals is the core of medieval
metaphysics, the doctrine is not considered at all in Gilson's The Spirit. In the Cambridge History it receives only one brief reference (p. 493), and it remains outside of consideration in De
Libera's determination of the place of medieval philosophy. One of the objectives of the present study is to show not only that the "forgotten" doctrine is important for our understanding of medieval
philosophy, but also that the idea of medieval philosophy as a transcendental way of thought does not exclude the other conceptions, but incorporates them.
The conception of medieval philosophy as transcendental thought expresses already in its terminology a moment of continuity with modern philosophy, for the term 'transcendental' is
generally reserved for the way of thought inaugurated by Kant.
Kant brings the project of his three Critiques together under the title of "Transcendental Philosophy," but he himself recognizes that this notion has a long tradition. In the
Critique of Pure Reason (B 113) he points to the 'transcendental Philosophy of the Ancients" and quotes the proposition "so famous among the Schoolmen: quodlibet ens est unum, verum, bonum," At the
same moment, however, he distances himself from the traditional conception. 'These supposed transcendental predicates of things are nothing else but logical requirements and criteria of all knowledge
of things in general" (B 114 ) . 'Transcendental' in the Kantian sense is concerned with the mode of our cognition of objects, insofar as this mode of cognition is possible a priori.
The Kantian perspective has strongly affected the study of medieval transcendental thought. An example of the connection of medieval thought with "modernity" is to be found in Kurt
Flasch's important study on Nicholas of Cusa which contains a chapter, entitled "Metaphysics and Transcendental Thought in the Middle Ages. (56) Flasch does not refer here to the doctrine of the
transcendentals, for he wants to take the term 'transcendental' exclusively in a Kantian sense, that is, as transcendental-logical. (57) Every transcendental philosophy, in his view, is based on the
idea that the world of objects is constituted by the human mind. Transcendental thought in the Middle Ages is therefore related to those thinkers who acknowledge a constitutive function of the human
mind, such as the German Dominican Dietrich of Freiberg (d.
after 1310), They show "a much more modern Middle Ages than it is generally supposed. "(58)
Yet this transcendental-logical approach seems questionable from a historical point of view. It makes the Kantian position the exclusive criterion for determining what
transcendental thought is in the Middle Ages. Medieval philosophers, however developed their own concept of transcendentality, and it is this way of thought that Kant called the 'Transcendental
Philosophy of the Ancients'.
It would be more appropriate historically and philosophically to consider the medieval doctrine as a distinctive form within the tradition of transcendental philosophy.
The French scholar S. 8reton wrote in 1963 that the doctrine of the Transcendentals is "classic and yet poorly known."·(59) His observation still holds. We only possess two general
studies on this subject, the first by H. Knittermeyer, the other by G. Schulemann.
Both studies go back to the 1920's and must be regarded as out of date. Their main shortcomings are that they do not pay sufficient attention to the historical and doctrinal
background of the formation of the doctrine in the thirteenth century and fail to give an explicit analysis of the notion of transcendentality. A new history of transcendental thought in the Middle
Ages is required.(61)
The focus in this book will be on Thomas Aquinas ( 1 224/5-1274), a representative of medieval thought, whose importance for the transcendental way of thought is often neglected or
underestimated. Although libraries have been written on his thought, and although we possess various studies of some aspects of his doctrine of the transcendentals, it is striking that a
comprehensive study of Aquinas's doctrine is lacking. This book will till this lacuna and wants to show that the doctrine of the transcendentals is not, as has been suggested, "a small, rather
insignificant part' of his metaphysics," (62) but is of fundamental importance for his thought. By the same token, the study will substantiate in an exemplary way the claims made in this section
concerning the conception of medieval philosophy as a transcendental way of
Thomas Aquinas was, however, not the first to formulate the doctrine of the transcendentals. The beginning of the doctrine is t0 be located in the first half of the thirteenth
century; it coincides with the introduction of a voluminous body of new philosophical literature into the Latin West. Not only the entire corpus aristotelicum, but also the writings of Arabic
philosophers become available in translation at this time. In the first chapter we will analyze the beginning of the doctrine of the Transcendentals. It is, of course, a requirement of modern
scholarship on Thomas t0 place his philosophy in its proper historical context. The first chapter provides the background for Thomas's transcendental thought and enables us to see its traditional and
innovative aspects," (pp. 21-24)
(56) K. Flasch, Die Metaphysik des Einen bei Nikolaus von Kues. Problemgeschichtliche Stellung und systematische Bedeutung, Leiden 1973, pp. 105 ff.
(57) See the extensive note in ibid., p. 103.
(58) Ibid., p. 156. Cf. on Dietrich of Freiberg K. Flasch, "Kennt die mittelalterliche Philosophie die konstitutive Funktion des menschlichen Denkens? Eine Untersuchung zu Dietrich
von Freiberg", in: Kantstudien 63 (1972), pp. 182·206.
(59) S. Breton, "L'idée de transcendantal et la genèse des transcendantaux chez Saint Thomas d'Aquin". in: Saint Thomas d'Aquin aujourd'hui, Paris, 1963. p. 45.
(60) H. Knittermeyer, Der Terminus Transzendental in seiner historischen Entwicklung bis Kant, Marburg 1920; G. Schulemann, Die Lehre der Transzendentalen in der
scholatischen Philosophie (Forschungen zur Geschichte der Philosophie lind der Pädagogik, vol. IV,2), Leipzig 1929.
(61) Cfr. J..A. Aertsen, "The Medieval Doctrine of the Transcendentals: The Current State of Research", in: Bulletin de la Philosophie médiévale, 33 (1991) , Pl'· 130-147.
See also the special issue of Topoi 11 (1992). devoted to the 'Transcendentals in the Middle Ages," (ed. J.J.E. Gracia) It contains contributions by J..J.E. Gracia, S. Dumont, J. Marenbon,
J.A. Aersten and S. MacDonald.
(62) L. Honnefelder, "Die Rezeption des scotischen Denkens im 20. Jahrhundert", in: Theologische Realenzycklopedie vol IX, sV. "Duns Sc0tus/Scotisumus II, Berlin/New York
1982, p. 233; id., Transzedentalität und Moralität. Zum mittelartelichen Ursprung zweier zentraler Topoi der neuzeitlichen Philosophie, in: Theologissche Quartalschrift 172 (1992).
———. 2012. Medieval Philosophy as Transcendental Thought. From Philip the Chancellor (Ca. 1225) to Francisco Suárez. Leiden: Brill.
Contents: Preface XIX-XX; Introduction 1; One. The Concept of transcendens in Medieval Thought: What is beyond and what is common 13; Two: Conditions, Presuppositions and
Sources of a Doctrine of the Transcendentals 35; Three. The Beginning of the Doctrine of the Transcendentals (ca. 1225): Philip the Chancellor 109; Four. The Doctrine of the Transcendentals in
Franciscan Masters [Alexander of Hales, Bonaventure] 135; Five. Albertus Magnus: Different Traditions of thought and the Transcendentals 177; Six: Thomas Aquinas: A First Model 209; Seven. Henry of
Ghent: The onto-theological transformation of the doctrine 273; Eighth. The German Dominican School: Dietrich of Freiberg and Meister Eckhart 315; Nine. Duns Scotus: A Turn in the Doctrine of the
Transcendentals 371; Ten. Discussions on the Scotist Conception [Francis of Meyronnes, Peter Thomae, Nicholas Bonet, Francis of Marchia] 433; Eleven. The Doctrine of the Transcendentals in Nominalism
[William of Ockham, John Buridan] 515; Twelve. Neoplatonic Critiques of Transcendental Metaphysics [Berthold of Moosburg, Nicholas of Cusa] 545; Thirteenth. The Doctrine of the Transcendentals in
Renaissance Philosophy [Lorenzo Valla, Pico della Mirandola] 569; Fourteen. The "Metaphysical Disputations" of Francisco Suárez: Between Scholasticism and Modernity 587; Fifteenth. The Doctrine of
the "Supertranscendentals": An Alternative Model? 635; Sixteen. Conclusion: The Importance of the transcendental way of thought for medieval philosophy 657; Bibliography 707; Index Nominum 741; Index
"The present work represents the completion of a research project that has engaged me intensively throughout my scholarly life. Its origins reach back to my inaugural address on the
occasion of taking up the Chair of Medieval Philosophy at the Free University of Amsterdam (1984). At the end of this lecture, Medieval Reflections on Truth, 'Adaequatio rei et intellectus',
I concluded that the idea of the transcendentality of truth underlies these reflections and announced that the medieval doctrine of the transcendentals "will be the subject of my research over the
This programmatic statement, typical of an ambitious new professor, turned out to be a fortunate choice. The choice had been motivated by a twofold interest. Historically, the
doctrine of the transcendentals is an innovative contribution of the Middle Ages to the history of philosophy; the origin of transcendental thought is not to be sought in modern philosophy but is
medieval. Systematically, the transcendental terms "being", "one", "true" and "good" concern what is first in a cognitive respect and what is fundamental; they express "basic" words of
The project resulted in a large number of studies, including the monograph Medieval Philosophy and the Transcendentals. The Case of Thomas Aquinas (1996). In the
Introduction, I advanced the provocative thesis of an intrinsic connection between medieval philosophy and transcendental thought, already suggested by the main title of the book. My argument was
that the theory of the transcendentals is essential for insight into the properly philosophical dimension of medieval thought, which is often developed in a theological context; medieval
philosophy can be regarded as a way of transcendental thought. The thesis provoked critical comments and questions: does it not presuppose an "essentialist" conception of medieval philosophy
and ignore its real diversity? In my view, the critique was based on a misunderstanding, which could only be removed by providing a complete history of the doctrine of the transcendentals that shows
the multiplicity of transcendental thought in the Middle Ages.
In 2003, on the occasion of my retirement as Director of the Thomas Institute at the University of Cologne, thirty-five colleagues, friends and students offered me an impressive
Festschrift with the title Die Logik des Transzendentalen. The editor of the volume expressed the hope (p. XXI) that the various contributions would stimulate the realisation of the planned
history of the doctrine of the transcendentals in a not too remote future. The Festschrift was indeed both a tribute and a stimulus." (from the Preface)