... personne avant Thomas, qui l'invente, Tempier, qui
l'institutionnalise, et Raymond Lulle qui la popularise, n'a soutenu
l'absurde doctrine de la double verité ...

Alain de Libera


J'ai essayé de montrer dans cet article que la célèbre dispute de la fin du XIIIe siècle concernant  la "doctrine de la double vérité" correspond à un es- pace théorique disputé entre plusieurs modèles concurrents du monde pro- mus par les universitaires parisiens; lisant attentivement les textes, au-delà des connotations esthétiques et affectives  par lesquelles elle fut le plus souvent interprétée, j'ai considéré que l'absence à l'intérieur des textes averroïstes de la doctrine proprement dite ne signifie pas nécessairement que ses opposants l'auraient inventée, mais plutôt que les suppositions théoriques averroïstes menaient vraiment, avec l'assomption de quelques prémisses strictement théo- logiques, à une doctrine de la double véri té, qui ainsi ne peut plus avoir aucun auteur concret déterminé. Par exemple, considérant la théologie comme une science dans le même sens où les artistes regardaient la philosophie, la con- struction de l'opposition entre la pensée pr édicative et l'intuition de la foi forme une théorie de la double vérité qui échoit rigoureusement à l'image que les théologiens pouvaient avoir du mouvement de l'averroïsme parisien.

The 13th century was one of the important furnaces of ideas for European thinking, grown out of the university debates taking place in the years 1270-1277. To meditate on the nature of the predicable in a context in which the great themes of thinking concerned the relations between Creator and creature meant a rigorous delimiting of the space of discourse from the area of the miracle. In addition, it can be maintained that this delimiting was analogous to a hier archical vision of the world, in which the spaces reserved to discoursing on the univ ersal concept corresponded at most, in the realist version, to the existence of universals, whereas human discourse st ood no chance of legitimisation when referred to realities superior to universals. This analogy justifies why Greek and Arab neo-Platonism, infiltrated into the Latin philosophic milieus of the century, gave rise to an important disputation concerning the nature of rational discourse, the legitimacy of theology as a rigorous science, and the role of miracle in discourse.


At the beginning of the 14th century, Raimundus Lullus1 wrote several ample commentaries of the 219 theses censored by Bishop Tempier of Paris on March 1, 1277 2. In his text, Raimundus denounces two Parisian thinkers, Siger of Brabant and Boetius of Dacia, on account of professing a doctrine of the "double truth" which contended that some propositions of science could sustain a truth opposed to the truth of the propositions of faith, without ei ther of these two coherent systems of propositions entering a conflict with the other. The history of this accusation can be given on two planes.

One of them refers to the fact that, with c onstancy going throughout the history of medieval philosophy since the 11 th century, the conflict between reason and faith was announced by such an expression as Petrus Damianus', where philosophy was an " ancilla theologiae"3 (an expression that had no philosophical value, because neither philosophy nor  theology had in the eyes of the monk the clear significance of distinct sciences), or by St An selm, who attempted a reconciliation between the two terms in his well-known phrase "fides quaerens intellectum"4. In the earliest historiographies of medieval philosophy, this broad plane of the disputation assimil ated the theme of the double truth disputed in the 13th century5 with the generic relation between faith and reason.

I maintain that this superposition is unwarranted  because it does not retain that the "double truth" disputation generates a second level, much  more particular, of the relation between faith and reason. The dispute in question was in fact connected  to the particular plane of the conflict between theology (professed as an autonomous science only at the beginning of the 13 th century 6) and the Greek-Arab paradigm of thinking, which had come as an unforeseen novelty in the area of Latin scholasticism and brought with it an extremely rigor ous understanding of the hierarchy of the world and the objects of knowledge. Setting the issue of the "double truth" in relation to this particular aspect of the disputations, I hope to present a history and an  interpretation of it in much more detail than its purely generic analysis might grant.


The documentary history of the period 1270-1277 records two texts of an official character that announce the conflict between reason and faith, in its particular occurrence that would stem from the disputation between theologians and "artists" (i.e., masters and students of the Faculty of Arts). The first of these texts is a document pronounced on Apri l 1, 1272 in the Church of Saint Geneviève from Paris, by which it was forbidden to anyone in  the university milieus of Paris to pronounce theses contrary to faith:

Being convoked for this reason all the masters an d each of them in the Church of Saint Genevieve from Paris we decide and command  that none of the masters and of the bachelors of our Faculty should ever engage himself in the determination or in the discussion on a theological problem, as would be on the Incarnation or on the problem of Trinity and the other similar top- ics, going far beyond his own established limits;  as the Philosopher said: it is entirely unfitted for someone who does not have the knowledge of geometry to dispute with someone who does. ... moreover we decide that if someone disputes somewhere in Paris any problem which seems to concearn both philosophy and faith, and if that per son determines it contrary to our faith, then he is going to be rejected as a heretic from our community forever...7

The value of this text is outstanding because it  extracts from Aristotle a principle of the autonomy of knowledge, while targeting this principl e against the Aristotelians themselves. The first part of the interdiction is clear: it is desired that the autonomy of theology should be established in relation to philosophy, a statement which leads one to think of a principal separation. Still, the second part contradicts the newly framed principle of autonomy by propounding the idea that it might be possible for some (common!) problems to be solved either  in favour of faith, or in that of science. The historical consequence (a courageous one, reached  with admirable academic consistency), was the separation of the Faculty of Arts from the University, so that for three years (until 1275, when Pierre of Auvergne reunified the University) there were two rectors in Paris, and a document appears to suggest that the rector of the "artists" was none other but Siger of Brabant 8. Nevertheless, all that the text from 1272 warrants us to assume for the time being  is that there are problems which might be settled in favour either of faith or reason. Much more ra dical is instead the formulation of the document from 1277, which itself mentions a theory of the double truth that it condemns:

In order to avoid the appearance of actually  sustaining what they sugest, their answers are so uncertain that when they whish to avoid Scilla, they are crushed by Caribda. They say that ac- cording to philosophy some facts are true, but not true according to catholic faith, as if two con- trary truths could exist...9

The formulation of the two truths, as I have ment ioned earlier, was quite an influential factor in the reception of Averroism as professed by Siger and Boetius, the consequence being that the philosophy of the two "artistae" was categorised as sophistic. Still, the document itself warns of the fact that Averroist texts were not as clear as they appear ed with respect to the truth-value of the theories that they asserted. The masked, understating nature  of Siger's texts on the theory of the universal existing in itself has already been remarked. The idea of a discourse prepared for the censors does not appear to be an absolute novelty because, a few de cades before the events of 1277, Roger Bacon had remarked about the artists that their discourses did not always have as an aim the proper expression that would facilitate understanding, but they were rather striving to introduce Averroist theses in forms difficult to recognise10:

Saying that neither through philosophy one could say otherwise, nor by the way of reason one could obtain anything else, but only through fa ith, they pale each time when the error of Averroes is announced. But they lie as the most common heretics.11

The accusation of insincerity formulated by Roge r Bacon might have a particular purport. It is known about Siger of Brabant that he was often wont  to dissimulate his true theoretical position. For instance, with regard to the theory pronouncing the unity of intellect, in his  Commentary to Liber de Causis, Siger pays polite reverence to the Christian faith without renouncing the premises that lead him to the thesis of the unique intellect 12. Instead, as we shall see, the accusation cannot be extrapolated to refer also to the text of Boetius of Dacia,  On the Eternity of the World, in which we find once more the bases for the Averroist formula of truth13.

Let us remark, however, that the accusation of the double truth did not surface only in 1272 and in 1277, but was already present in 1270, in  the closing of Thomas Aquinas' treatise  On the Unity of intellect and was directed at Siger of Brabant14:

[123.] It is more serious what he says in the following words: "I necessarily conclude through reason that the intellect is one in number; but without avoidance I sustain through faith the opposite." Therefore, his opinion is that the faith deals with some facts from which one could contradictory conclude by necessity. But because by necessity one could conclude only on those who are truly necessary, whose opposite is impossible and false, it results from what he said that faith should be concearned with the impossible false, with what God couldn't do: but the ears of the true belivers cannot be put through this. He doesn't courageously keep himself close to those which do not belong to philosophy but to pure faith and he dares to discuss the latter; for exam- ple, if the infernal fire affects the soul, and he dares to say that the opinions of the doctors on the question have to be refuted. He could dispute with a similar argument the question of the Trinity, the Incarnation and others of the same kind a bout which he could talk only with an unclear sight.15

As Bruno Nardi has stated 16, and as Borbély Gábor has vouched in the Hungarian edition of the treatise by Saint Thomas17, no such citation is to be found among the treatises that have remained from Siger. This fact is extremely important: it might me an that St Thomas was, in a sense, inventing his adversary in order to refute him, exaggerating his position. We do not know whether Siger of Brabant was, at an initial stage, of the opinion that there were two truths, yet the texts that have remained from him, as we shall see below, are more ambiguous  than St Thomas would wish to expose them as. All those four passages that we have examined (to the best of our knowledge, the only ones in the period that brought the accusation of the "double truth", which is precisely the reason why I have preferred to quote them in extenso) rise a number of questions: who was  the one who invented the theory of the double truth: Siger of Brabant, Boetius of Dac ia, St Thomas Aquinas, or Etienne Tempier? Likewise, what was the position of Averroism itself with respect to the theory of truth?


Resorting to the cliché launched by Raimundus  Lullus, Sajó Géza, the editor of Boetius'  On the Eternity of the World 18, states that, for the historiography of medieval philosophy, the discovery of Boetius's treatise confirms the presence of the double truth doctrine within the current of Latin Aver- roism19. In a famous volume, employing a quaint formul ation (without reference) of the double truth, Jacques le Goff had maintained precisely the same  idea, namely that the Averroists were those who "invented the doctrine of the double truth "20. The myth of this theory, launched by historians of medieval philosophy, has made a career starting with Victor Cousin and P. Mandonnet, up to, more recently, M. de Joos21.

On the other hand, the contrary opinion to that  maintained by the aforementioned authors was shared by such authors as Etienne Gilson, F. van  Steenberghen, and Alain de Libera. In an exposition from 1955, Etienne Gilson 22 claims the fact that none of the known Averroist texts contains an affirmation of the double truth, that it constitutes a subsequent and disingenuous myth, and that, to the contrary, all that the treatise by Boetius of Daci a attempts is to assert the autonomy of sciences in relation to faith. Gilson remarks a fact that is extre mely important to our discussion, in what concerns master Boetius: in On the Eternity of the World , the opposition is never established between  philosophia and theologia, but always between philosophia and fides. This means that the truths of the two domains have no point of contradiction, because one of them refers to a truth in itself ( simpliciter), while the other has a relative significance ( secundum quid); he identifies a passage in Boetius' treatise which, indeed, brings this duality into relief and at which I  shall refer in my turn,  in the paragraph bellow. To the same extent, F. van Steerberghen has remarked  upon the inadequacy of categorising heterodox Aristotelianism (the name he gives to Latin Ave rroism) as a doctrine of the "double truth", a fact ostensibly invalidated by Siger's treatises23.

Alain de Libera has pursued two distinct contentions with regard to the origin of this myth. This situation is somewhat disconcerting considering that, in 1991, in his work  Penser au Moyen age 24, the medievalist gives the suggestion that the treatise that  induced Tempier to write the foreword of the censorship document was indeed that of Boetius of  Dacia, inasmuch as Tempier rejected the idea of a peaceful coexistence of faith with philosophy, in the form proposed by Boetius 25. This fact would indicate that Tempier invented the doctrine himself, yet Alain de Libera does not further specify, this time, what was the reason why Tempier rejected the doctrine, as long as it did not announce any contradiction with faith. On the other hand, in 1994, in his preface to the French translation of St Thomas Aquinas' treatise On the Unity of intellect, Alain de Libera considers § 123 of the Thomist text, quoted above, and remarks upon the double truth as being a "piège logique" that St Thomas was setting for Siger of Brabant 26. This conjecture would imply that Tempier's formulation was, in fact, but a resuming of an idea of Thomas Aquinas' or, which is extremely plausible, the product  of an intellectual climate of the faculty of arts in which tolerance for some version of the double truth might have been a fact.

However things might have stood, even if it is  virtually impossible to reconstruct the exact historical disputation because of the physical im possibility of knowing the totality of the text that circulated at that time, it is clear that we ca n determine neither the fa lsity of the double truth nor whether its attribution is correct. The reason is th at the question that I have implicitly formulated above (who was that who launched the theme of the  "double truth"?) is one that has a historical and philological horizon; on the contrary, we might ask ourselves "what is the proper sense of the doctrine, irrespective of who was it that first formulated  it?". By posing the question in this way, one is in the position to take a step, a small but a novel one, in  the research on this issue, so that it is evident now that the philosophical import of the theme must be  divided with respect to the dispute between Siger and St Thomas, on the one hand, and on the other,  with respect to the disputation between Boetius and Tempier's commission of censors.


Alain de Libera has shown in his analysis that, in  Quaestiones in tertium de anima, IX, and later in De anima intellectiva, VII, Siger of Brabant thought that God could not effect contraries at the same time, and making multiple intellects was such a c ontradictory accomplishment, because matter alone multiplies, while the intellect was immaterial. As lo ng as Siger never states what he beliefs with any clarity, St Thomas was, according to de Libera, setting him a logical trap: divine omnipotence should be believed in through faith, while the theory of the un ique intellect was said to result solely from the assumed philosophical principles (matter that individu ates the species). This, for de Libera, means that Siger did fall into the trap laid by St Thomas, namely by asserting in  De anima intellectiva, VII that in the undecided or heretical situations of philosophy one ha d to follow the faith that goes beyond all human reason27. Even this being the case, it does not follow  that Siger followed the doctrine of the double truth. To the contrary, in the same treatise he invoked a precept concerning the autonomy of the sciences28 in relation to the divine miracle:

Nothing concearning ourselves, but related to God's miracles as long as we normally talk about those of nature...29

The principle is twice important: it is taken even fr om the work of St Thomas Aquinas, who had inherited it from Albertus Magnus 30, and it came to influence Boetius of Dacia, the creator of a system of the autonomy of sciences in direct relation with the idea that the beginning of creation is indemonstrable. Hence, one observation can be joined with de Libera's analysis: irrespective of whether it was St Thomas or Siger that originated the doctrine of the double truth, both  the one and the other were about to engage in a discussion on the value of  truth that neither of them had fully clarified. St Thomas had, for instance, given his opinion that  the eternity of the world was a coherent thesis, although invalidated by faith, while Siger affirmed the unity of intellect, although he says that the impera- tive of his faith compels him to follow the contrary of this idea. All this indicates that what was at stake from the philosophical point of view in the theme of the double truth has not yet been accounted for in discussing the conflict between Siger and St Thomas.


Master Boetius announced in his treatise th at there was no contradiction between faith and philosophy. I have quoted earlier that Etienne Gilson has remarked the absence of the term theologia in this text; still, the reputed medievalist has left this  event uncommented from the point of view of the possible status of theology, in Boetius' thinking.  Boetius' text brings one clarification with respect to faith and philosophy: " And then, there is no contradiction between faith and the philosopher. [...] For this reason, the Christian, provided he comprehends with subt lety, is not constrained that from his law to obliterate the principles of philosophy, but saves both faith and philosophy"31

The logic in which this is achieved is valid only in  the event in which there is a hierarchy of the world, in which the sublunary world has as a plane  superior to itself the skies and then God and also where there is, symmetrically, one ‘specialist' for each  type of reality, which is to say, a naturalist, a mathematician, and a metaphysician.  Yet this was the very gist of Boetius' text: the eternity of the world has to be a working assumption for the natu ralist and for the mathematician (because both of them study motion, the real and the ideal), but also for the metaphysician, because the latter studies the prime cause in its quality as  sufficient cause, and not as  voluntary cause (because the latter cannot be known)32. From this scheme results that science comprises the whole field of the real. The most impor- tant observation is that here to faith might correspond at most the prime cause in the sense of voluntary cause, yet to theology cannot correspond anything, because, in the given scheme, it does not vie with metaphysics.

For this reason, the thesis that I would endeav our to establish, in prolongation of Gilson's observation concerning the absence of Boetius' considerations on theology, amounts to the fact that precisely the  absence of the term under discussion from the text confirms the fact that Boetius' intention was polemical, inasmuch as he could not, w hen the eternity of the world was admitted as a working assumption for any science in general, admit that theology is a science, because it did not have a discursive object. This converges also with what  Boetius had stated in his treatise on the mission of the philosopher, insofar as "there can be no issue that  can be disputed through arguments which the philosopher is not bound to debate and to determine,  with respect to how in particular truth is to be found in it ..."33 By way of consequence, the dissociation of the concept of God into sufficient cause and voluntary cause (or else, a God of ‘philosophers' and a living God) splits the unity of theology, because it either states the truth, and in that case it is not to subject to dispute, or it is disputable, and then it does not state the truth. This is, in my opinion, the motive that drives not only St Thomas, but also Tempier, to judge as guilty of the double tr uth the people who undermine their own theological cogitation. In essence, Boetius demonstrates in the subtext that reason and faith do not come into con- flict if and only if theology is not a science. In favour of this assertion there are two arguments that I can bring.

The first is represented by a passage of the treatise that shows why, from a logical point of view, faith and reason do not contradict themselves. The  passage has already been remarked by Alain de Li- bera34, who uses it in order to propound the fact  that reason being put on the same plane as faith would mean a fallacia secundum quid et simpliciter , already exposed by Aristotle in  Sophistic Refutations, 25, 180a-b. The sophism amounts to saying, for instance, that Socrates is simultaneously white and non- white, if he is white in truth while his hair is black,  so weighing an absolute statement in relation with a negative one. Master Boetius does indeed suggest this possible relation35:

The conclusion by which the naturalist says that the world and the firs mouvement couldn't be new is false if we take it  absolutely (absolute) by itself, but if one recalls the arguments and the principles from which such a conclusion is inffer ed, it will result from them. And we know that both the one who asserts that "Socrates is white" and the one who denies it speak with truth  in a certain way (secundum quaedam).36

The opposition between  absolute and secundum quid is convincing in the text: it means that the propositions of faith are absolute, while those of science are relative. Yet this observation is not, in my opinion, sufficient, because Boetius' observation  does not fall entirely under the sophism enounced by Aristotle. In fact, Boetius had already announced  the frame in which philosophy (whose branches are physics, mathematics, and metaphysics, ordered by t he planes of the world) had to place itself in relation to its problems: in the passage quoted above, the philosopher was under the duty to determine all that pertained to the sphere of dispute with ( disputabile) arguments. This means that no affirmation made absolute (or: simpliciter) falls under the province of the philosopher, while, on the other hand, the word disputabile and the expression secundum quaedam are synonymous. From this observation results that affirmations made simpliciter (those that pertain to faith) are not knowledge properly so called (as is, however, the proposition "Socrates is white", and this would be the difference between Boetius and Aristotle's sophism). The result is the fact that  philosophy absorbs the entire domain of knowledge (that can be formulated in propositions or, in other words, in relationships secundum quid between pre- dicate and subject).

What remains, therefore, is that theology is not a science but, tentatively, the subject of a tacit polemic of Boetius', which would fully motivate Te mpier's reaction. Besides, if it is true that the difference between Boetius and Tempier was that t he former did not believe that theology was a science (and consequently that there can be no room  for theologians within the university), then we can also clarify the historical-philological aspect of  the "double truth" disputation: we should not bank our account on malicious intent coming from any of  the persons involved in the polemic, but we can simply maintain that, convinced that theology was not a science, Boetius applied the distinction secundum quid/absolute to the philosophy of faith; to the contrary, in the eyes of Tempier, who admitted that theology was a science and that it was it s lot to deal with disputable problems (which, by consequence, would give it a place in the university), Boetius' statements inevitably produced the double truth without malicious intervention from Tempier. As a result, only the elimination of theology as a science could also eliminate the double truth.

The second argument that could be invoked in favour of the idea that the way in which theology is or not considered a science regulates, in re ality, the relation betw een faith and reason is the competition against which Boetius wrote his treatise.  In essence, Boetius maintained the fact that any discourse that produces knowledge deal with nature, with the sky, or with the sufficient cause of all and is, by consequence, a branch of philosophy that "reflects the entire being, in a natural, mathematical, or divine sense"37. This implies that all possible sciences ar e subordinated to philosophy. One cannot ex- clude the possibility of this message being polemically  targeted against the idea that all sciences are subordinated to theology. This idea had been maintai ned only a few years prior to Boetius' writing by Saint Bonaventure in a famous treatise, On the Reduction of Arts to Theology, in which he had claimed that the entire domain of knowledge was reducible to theology, because in any science one discovers a structure analogous to Trinity, which forms the pr oper scope of Scripture interpretation, or else, a theology with an evident hermeneutic character 38. The institutional opposition between the faculty of arts and that of theology, analogous to a co mpetition between the theologian and the secular intellectual (already remarked by Alain de Libera 39) could, in my opinion, be analogous also to a competition between the idea (maintained by St Bo naventure) that theology is the fundament of any science and the idea (present in the subtext of B oetius' treatise) that theology is not even a science, because about the volition of the living God there can be no dispute.


In result of this analysis, we may claim that it is  possible that the fundament of the double truth myth should be not merely non-verifiable, historically, in Averroist texts, but also something other than a malicious invention of the censors of Averroism. In  reality, the myth of this theory could have come from a misreading of Siger's intentions from the  part of St Thomas Aquinas, or of Boetius' intentions from that of Tempier, against the positively c onflicting background in which theology is, generally speaking, situated.

If to Siger and especially to Boetius, a much more rigorous and careful thinker than the master of Brabant, theology is not a science, then there is no double truth, because the truth secundum quid is the only one that produces knowledge, whereas the other,  that of faith, has a ro le that we might say, liminally, that it exceeds human discourse. If, to  the contrary, this discourse was not beyond the scope of human language, as St Thomas Aquinas and eq ually Etienne Tempier presupposed, then Boetius' demonstration, joined to the idea that theology was indeed a science,  appears to be indeed giving voice to a double truth, no matter how dear might have been to Boetius's mind the idea that he might defend himself of this accusation by invoking  fallacia secundum quid et absolute : in that case, theology and philosophy remain irreconcilable.

I must observe that, if Siger had not maintained  the unity of intellect, there would have been no thought that God cannot create several souls (in  the context in which we accept an Aristotelian definition of the soul) and with it, no "logical trap"  as offered by Aquinas. In essence, this logical trap reveals that, if we place the Aristotelian paradigm  of knowledge to a theology that wishes to be accepted as a science, we rigorously obtain a double , and absurd, truth, whereas if we realise the fact that theology is not a science, the double truth disappears.

In the same way, if we resume, in the wake of B oetius, the idea that the world is eternal, what results is the fact that the domain of philosophic sciences cover the hierarchy of the world, without leaving room for theology. In case room for theology was nevertheless made, it would have meant that creation was rationally demonstrable, or else, all that  Boetius would not allow reason to achieve. In a way similar to the previous situation, the admission of  theology as a science could have given rise to a double truth (in between the situation of metaphysic s and theology), while its dismissal eliminates any possible contradiction within the disputable propositions. The true meaning of this disputation can offer an image on the possible relation between miracle and  discourse. Latin Averroism, in fact develops an excellent secular example of a discourse on the miracle: maintained within the rigorous province of the ineffable, the miracle is indirectly signalled through a clear delimitation of the predicable space, reserved to what is human.

1 Lullus, Raimundus, Liber reprobationis aliquorum errorum Averrois, in Opera latina, ed. Keicher, Paris, 1978, or Liber de naturali modo intelligendi, in Opera latina, ed. Keicher, Paris, 1978, or  Declaratio Raimundi super modum dialogi edita , in Opera latina, ed. Keicher, Paris, 1989.
2 For the text of the censored propositions, cf. H. Denifle, E. Chatelain, Cartularium Universitas Parisiensis, Paris, 1889- 1897, vol. I, pp. 543-555.
3 Cf. Petrus Damianus, De divina omipotentia, in PL, vol. 145, coll. 603.
4 Cf. St Anselm of Canterbury, Proslogion, ch. I, in PL, vol. 159, coll. 227.
5 The proof for this event can be found in the succession of  early histories of medieval philosophy, in which M. de Wulf, B. Haureau, or V. Cousin stated that the rel ation between faith and science represented one of the undifferentiated constants of medieval thinking.
6 Cf., in support of this statement, Amos Funkenstein,  Theology and the Scientific Imagination , Princeton, 1986 (Romanian edition, Humanitas, 1996, p. 11), and especially M.D. Chenu,  La theologie comme science au XIIIe siecle , J. Vrin, Paris, 1969, p. 9.
7 ... convocatis propter hoc magistris omnibus et singulis in ecclesia sancte Genovefe Parisiensis, statuimus et ordinamus quod nullus magister vel bachellarius nostrae Facultatis aliquam quaestionem pure theologicam, utpote de trinitate et incarnatione sicque de consimilibus omnibus , determinare seu etiam disputare praesumat, tanquam sibi determinatos limites transgrediens, cum sicut dicit Philosophus, non geometram cum geometra sit penitus inconveniens disputare ... statuimus insuper et ordina mus quod si quaestionem aliquam quae fidem videatur attingere simulque philosophiam, alicubi disputaverit Parisius, si illam contra fidem determinaverit, ex tunc ab eadem nostra societate tanquam haereticus perpetuo sit privatus ...
8 Cf. Chartularium ..., p. 523, document No. 460, which contains the expression " Procurator vero partis adversae, quae pars Sigerii communiter nominatur ...".
9 Ne autem, quod sic inuunt, asserere videantur, responsiones ita palliant quod, dum cupiunt vitare Scillam, incidunt Caribdim. Dicunt enim ea esse vera secundum philosophiam, sed non secundum fidem catholicam,  quasi sint duae contrariae veritates ...
10 Cf. Roger Bacon, Communis naturalium, I, 1, R. Steele, p. 286  apud R. Macken, Revue des Sciences Philosophiques et Theologiques, 1971, p. 217.
11 Palliant ergo errorem suum quando arctantur, dicentes  quod per philosophiam non potest aliter dici, nec per rationem potest haberi aliud sed per solam fidem. Sed mentiuntur tanquam vilissimi haeretici.
12 Cf. Siger de Brabant, Quaestiones super Librum de causis, A. Marlasca, Louvain-Paris, 1972, chapter 27.
13 Cf. Boetius of Dacia,  Tractatus de aeternitate mundi, editio altera  auctoritate codicum manu revista et emendata , Sajó Géza, Berlin, Walter de Gruyter et Co., 1964.
14 Cf. Sancti Thomae Aquinatis tractatus De unitate intellectus contra averroistas, edition critica, <curavit> L. W. Keeler, Pontificia Universitas Gregoriana, textus et documenta, series Philosophica, 12, Roma, 1936, §. 123.
15 [123.] Adhuc autem gravius est quod postmodum dicit: " per rationem concludo de necessitate, quod intellectus est unus numero; firmiter tamen teneo oppositum per fidem ". Ergo sentit quod fides sit de aliquibus, quorum contraria de necessitate concludi possunt. Cum autem de necessitate concludi non possit nisi verum necessarium, cuius oppositum est falsum impossibile, sequitur secundum eius dictum quod fides sit de falso impossibili, quod etiam Deus facere non potest: quod fidelium aures ferre non possunt. Non  caret etiam magna temeritate, quod de his quae ad philosophiam non pertinent, sed sunt purae fidei, disputare  praesumit, sicut quod anima patiatur ab igne inferni, et dicere sententias doctorum de hoc esse reprobandas. Pari enim ratione posset disputare de trinitate, de incarnatione, et de aliis huiusmodi, de quibus nonnisi caecutiens loqueretur.
16 Cf. Saggi sull' aristotelismo padovano dal secolo XIV al XVI, Sansoni, Firenze, 1958.
17 Aquinói Szent Tamás, Az értelem egysége, fórditotta és gondozta Borbély Gábor, Budapest, Ikon Könyvkiadó, 1994.
18 The text was discovered by the Hungarian researcher in a private collection of anonymous manuscripts in Budapest and subsequently identified as the purportedly lost opuscule by Boetius. Cf.  Un traité récemment découvert de Boéce de Dacie  De mundi eternitate, texte inédit avec une introduction critique  par Sajó Géza,  avec en appendice un texte inédit de Siger de Brabant Super VI Metaphysicae , Budapest, Akadémiai Kiadó, 1954, reprinted in Berlin in 1964 (for the second edition, cf. supra).
19 Cf. the 1953 edition of the treatise, p. 37.
20 Cf. J. le Goff, Intelectualii în Evul Mediu, Meridiane, Bucharest, 1994, p. 126.
21 Cf. M. de Joos, L'actualité de Boèce de Dacie, in Dialogue, 1967-1968, pp. 527-538.
22 Cf. E. Gilson, Boèce de Dacie et la double verité, ADHLMA, XXX, Paris, pp. 81-99.
23 Cf. F. van Steenberghen, La philosophie au XIII e siècle, Louvain, 1966, p. 389: "Let us first note that there is no trace in Siger's writings of the famous theory of the double truth that has often been attributed to him after P. Madonnet."
24 Cf. Alain de Libera, Penser au Moyen Age, Seuil, Paris, 1991.
25 Cf. Alain de Libera (1991), pp. 123: "This is precis ely what Tempier rejects: the possibility of a peaceful coexistence of the philosopher and the believer. For this reason, he invents the double truth."
26 Cf. Thomas d'Aquin, Contre Averroes, trad. d'Alain de Libera, GF-Flammarion, Paris, 1994, pp. 51-58.
27 Cf. ed. Bazan, p. 108, r. 83-87.
28 Cf. ed. Bazan, p. 84, r. 47-48.
29 Sed nihil ad nos nunc de Dei miraculis, cum de naturalibus naturaliter disseramus.
30 Cf. Albertus Magnus,  De generatione et corruptione , in Opera, vol. IV, p. 363 and Saint Thomas Aquinas,  Summa Theologica, I, q. 76, a. 5, ad 2m.
31 Cf. Boetius of Dacia, op. cit., §. 12.
32 Cf. Boetius of Dacia, op. cit., §. 9.
33 Cf. Boetius of Dacia, op. cit., §. 7.
34 Cf. Alain de Libera, op. cit., §. 8.
35 Cf. Boetius of Dacia, op. cit., §. 8.
36 Unde conclusio in qua naturalis dicit mundum et primum motum non esse novum, accepta absolute, falsa est, sed si referatur in rationes et principia ex quibus eam concludit, ex illis sequitur. Scimus enim quod qui dicit Socratem esse album et qui negat Socratem esse album, secundum quaedam uterque dicit verum.
37 Cf. Boetius of Dacia, op. cit., §. 7.
38 Cf. St Bonaventure,  On the Reduction of Arts to Theology , bilingual edition, translated by Horia Cojocariu, Charmides, Bistria, 1999.
39 Cf. Alain de Libera, Penser au Moyen Age, Seuil, 1991, pp. 240-245.