A Brief Look at the Life and work of St. Thomas Aquinas and His Impact on Scholastic Philosophy


by Fr. Raymond Taouk




st. Thomas aquinas


1) life and works


1.    Life. Thomas Aquinas (1225-1274) was born in Roccasecca near Naples. He studied as a child (aged 7) at the monastery of Monte Cassino. In 1239, he studied the Trivium under Peter Martin, and the Quadrivium with Peter of Ireland. In 1244, he becomes a Dominican at Naples, and is sent to Paris. His brothers oblige him to return to Roccasecca and he is freed the following year. He finally goes to Paris in 1245 and studies under St. Albert the Great until 1248, and follows him to Cologne. In 1252 he returns to Paris and obtains the grade of licence in Theology in 1256, and Master’s degree in 1257. He teaches as such until 1259, when he returns to Italy teaching in various cities, Agnani, Orvieto, Rome and Viterbo. He returns to Paris in 1269 where he remains until 1272, when he goes to teach in Naples. Called by Gregory X to attend the IId Council of Lyons in 1274, he dies on the way at Fossanova (March 7). Soon canonised & named Doctor Angelicus.


2.    His teaching was in advance to that of his time in many ways.

·      ‘Erat enim novos in sua lectione movens articulos, novum modum et clarum determinandi inveniens, et novas inducens in determinationibus rationes, et nemo qui ipsum audisset nova docere et novis rationibus dubia definire, dubitaret quod eum Deus novi luminis radiis illustraret, qui statim tam certi cœpisset esse judicii ut non dubitaret novas opiniones docere et scribere quas Deus dignatus esset noviter inspirare.’

·      Also, given the disorders in the Fac. of Theology provoked by the Secular clergy who considered the Regular clergy to be inapt for teaching, STAq inaugurated the ‘Disputationes Quodlibetales’ in 1256 to answer all the questions on any given topic of philosophy or theology, presented before teachers and students alike. They took place twice a year (Easter and Christmas) touching on topical problems, which gave birth to the XII Quodlibetales.

2) struggle against averroists and augustinians


1.    Averroism. ST fought against the Averroism of Siger de Brabant (1235-?), the most famous University teacher during the years 1265 until ST’s return. Here are some of his doctrinal tenets:

·      In Mphcs, to precise the relation betw. God and the world, he uses the principle of symmetry whereby to each act must correspond a passive potency, to the form a matter, to the accident a substance, to the Pure Act the logical power of existing.

·      Following Avicenna and Averroes, he affirms that the immediate effect produced by God, the first intelligence, is necessary, eternal and unique. The other intelligences derive from the first following also the law of eternal necessity. He still leaves room for contingency with regard to the mixture of causes in the sublunar world. He maintains the system of celestial spheres which come necessarily and eternally from the creation of God.

·      In psychology, he maintains the thesis of the unicity of the intellect. Given that intellection is inorganic, the int. soul cannot be the form of the body. Given that the body is the only element which provides the numerical -material- multiplicity, it follows that the human intellective soul is one and unique. Men are distinguished by their external and internal senses. This thesis destroys the personal immortality.


2.    Refutation of Averroism. St. Bonaventure, and after him and more than him, ST will fight strenuously agst the errors of Siger which were attacking the dogma.

·      The main error regarded the unicity of the intellect. ST refutes it on the philosophical ground, based on the Aristotelian definition of the soul ‘actus primus corporis organici’, which has four functions including the understanding.

·      ST shows how daring it is for a Christian to place a contradiction betw. his philosophy and faith. Such a man must logically admit two truths, one natural and the other supernatural, which can contradict each other. Slowly, Siger will join the Thomist position in psychology but not in his cosmogony with regard to the eternal necessary spheres.


3.    Augustinianism

·      As a reaction to the erroneous commentaries of Aristotle, and without regard to the distinct pure Aristotelism of the Thomists, the Augustinians held different view points :

·      In theology, it was more a current than a systematic school of thought, designed to maintain the theological spirit of St. Augustine re. the primacy of God, the doctrine of exemplarism, a definitive mysticism and moralism (man must act together with grace to submit himself to it). In this, ST is perfectly Augustinian.

·      In philosophy, there appears an eclectic construction which unites Neoplatonism together with Aristotelism. St. Bonaventure is the creator of this philosophy authentically Augustinian. For him as well as for other eclectics, St. Thomas appears too daring in defending the main theses invoked by Siger which were in opposition to those cherished by the Augustinians. They differ:

·      ST distinguishes and maintains the autonomy of reason in its own domain.

·      He rejects the seminal reasons and defends the absolute potentiality of prime Matter.

·      He excludes any matter from angels and from h. souls.

·      He teaches that the spiritual soul directly informs the body.

·      At the death of St. Thomas Aquinas, with the recurrence of the Averroist agitation, in 1277, the bishop of Paris, the Augustinian Tempier makes a syllabus of 219 condemned propositions, some of which were equally defended by Siger and St. Thomas. Tempier trespassed his rights and excommunicated the doctrines and the persons. Later, he was prevented by Rome from condemning those propositions which taught the unicity of the form in the Thomistic way. This condemnation signed the death of Sigerism and of the Latin Averroism, but the Dominicans who had taken ST as their official teacher considered as invalid those points of doctrine which condemned him, which were explicitly vindicated during his canonisation by John XXII in 1319.


3) creation of thomism


            Relying on the achievements of his predecessors, ST can build his own philosophy independently from any historical contingency, based on experience and common sense, the philo of being.

            In the XIIIth cent., Thomism was a fecund revolution ie. a profound change, not by way of a radical subversion or destruction, but by way of a positive and vital development and perfection. With the guidance of an excellent master in St. Albert the Great, of an excellent originator in Aristotle, of an excellent milieu in the Universities and the Dominican order, but also by his supernatural lights, he was able to collect the materials, to organise them under a directive principle through a powerful intellectual effort.[1] The result has a triple characteristic:


1.    Conservation of the materials.

·      He wants to preserve all the truths acquired until his time, and the extent and source of his information is enormous (Patristic collections ordered accdg to the subject matter; he searches for translations of Greek authors).[2] He does the job with :

·      discernment by a critical spirit, which allows him to discard the apocryphal texts attributed to Ar. or to St. Aug. He discovers the true author of the Liber de Causis, which allows him to interpret correctly those texts. He seeks chosen materials, in philosophy by completing Ar. with the neoplatonism of Denis Areopagyte, in theol. by the S. Script. and St. Aug.

·      interpretation. His aim is always doctrinal, the discovery of truth as opposed to what any author thought personally. Dealing w. obscure passages of Ar. or of St. Aug., he does not oppose them but gives them a sense sec. veritatem, which method he himself calls exponere reverenter.

·      hierarchy. He chooses those theses which are evident, based on experience and common sense, and takes them as the foundations of his philosophy as Ar. ‘proprium ejus philosophiae fuit a manifestis non discedere.’ He is very reserved when it comes to scientific explanations, as e.g. for the theory of the celestial planets.


2.    Novelty, the intellectual effort


·      The spirit and vision of the Thomistic world is a profound and moderate metaphysical vision. He judges everything according to the view point of God. He considers beings as such and seeks to explain their profound reasons. He gives them their experimental foundation. By his method inductive, experimental and progressive, he is Peripatetician. By his metaphysical outlook in which he delights, he is also Platonician. He is also analytical and synthetic:

·      Analytical, because he bases the divers sciences on experimental facts which correspond to them according their proper method :

- a priori definitions and deductions in metaphysics,

- introspection and facts of consciousness in psychology,

- a priori principles of duties and applications according to circumstances in Moral life,

- external experience in Physics.

·      Synthetic, because each detail is referred to invariable principles, the essence of his Metaphysics.[3]


3.    Progress, a directive principle. Inasmuch as human knowledge is the common good of reason, it should progress through the collaboration of thinkers of all times, in depending only on evidence and on God’s Revelation. From this comes his respect towards men of the past, including those who erred. From this also comes his full independence from any h. authority when it comes to philosophy ‘locus ab auctoritate quae fundatur super rationem humanam est infirmissimus’. A philosopher is worth what his argument is worth. From this also comes his confidence in explaining faith by philosophy, which would be illustrated and confirmed by the truth from above.


            4) philosophia perennis


1.    The natural philosophy must be in accordance with the natural tendencies of the human mind.  Such is the philosophy of ST since it is :

·      the philosophy of evidence : both experimental evidence of the sense data, and intellectual of the self evident first principles.

·      the philo. of being : it is regulated by being and reality.

·      the philo. of the intellect : since it is the philo. which believes and defends the true, object of the int., and since it educates the intellect with its discipline.


2.    This natural philosophy has therefore specific characteristics, it is   :

·      a universal philosophy : it does not depend on history/geography but on the nature of man.  It is universal because it is simply the elevation or technicisation of common sense.

·      perennial philosophy : it existed before in the natural pre-philosophical knowledge of things.  It still exists today as a living and progressive tradition.

·      an organic philosophy (one philo.) because :

·      it insures the harmonious unity between the sciences,

·      the same simple principles explain divers complex problems,

·      leaving aside any one principle would give a wrong view of the whole reality.



5) the fundamental principle of thomism


1.    Aristotle, although he was the most metaphysical Greek thinker of all times, thought as a physician because  his main principle stressed the distinction of Act and Potency. St. Thomas however, studies things from the standpoint of truth and he searches the principle which founds philosophy as such. This leads him to consider the real as totally intelligible, either bec. it is God or because. it is a participation of God. This central vision of Thomism synthesises the platonic principle of participation and the moderate realism of Aristotle. St. Thomas appropriates these Greek principles for his own use, not for historical reasons, but because. they are simply natural truths which deserve to be used.


2.    This principle of universal intelligibility is Quidquid esse potest intelligi potest.[4] Thus:

·      the object of philosophy is reality. This intelligible ‘id quod est’ is the real nature, independent from, exterior and anterior to, thought.

·      ‘Esse est actualitas omnium rerum’. Esse of itself is unlimited, infinite bec. of itself, it is pure perfection and act.[5]

·      the concept of being is analogical. It is not a supreme genus but a transcendental concept.

·      When it is limited in concrete things, being exists as a composite of Act and Potency.


3.    This principle of universal intelligibility has validity in :

·      criteriology, bec it affirms the correct correspondence of judgement with the exterior thing.

·      psychology, bec. the intellect has priority over the will. The int. has a double object : one adequate which is being, the other properly human which is the essences abstracted from the sensible. Thus, man has the natural desire to see the essence of God.

·      logic, bec. it precises the analogical value of the concept of being.

·      metaphysics especially. From being, we move on to other universal characteristics, the transcendentals. From the transcendentals, we induce the first principles of reason. Change and multiplicity of being is explained by the distinction of act and potency (keystone of Aristotelism). ST does not see so much the physical aspect of these formulae, but he seeks in creatures a means to rise to the pure perfections and to acquire some knowledge of God.


6) the method of knowledge of thomism


1.    Starting point : intuition

·      sensible intuition of the concrete being (rich in precision, poor in extension).

·      intellectual intuition (poor in precision, infinite in extension) of things outside oneself but also of one’s own conscience.

·      intuition of common sense which provides with the first principles of thought, object of the habit of ‘intellectus’. This intuition extends to the speculative principles and the practical principles of the synderesis, respectively starting point of wisdom and moral science.


2.    Discursive intelligence : The induction is the first step of reasoning which concretises the first principles drawn from concrete cases and induces proper definitions and general principles of Metaphysics.


3.    Deduction-demonstration. Once the definitions and principles have been drawn by induction, the second step produces the proper science, int. knowledge in a still imperfect degree of a determinate essence/subject matter. This occurs through the demonstrative syllogism.


4.    The systematisation terminates the knowledge of reality, by ordering the sciences. Such an ideal state of science is unreachable in the case of :

·      God due to his excess of perfection and our need to know Him through the mirror of creatures.

·      the individual because its excess of impfct, remains unpenetrable (Mat I). Scientia est universalium


iv. the scientific tradition


            The University of Oxford followed the Platonic-Augustinian philosophy during the XIII cent, as taught esp. by the school of Chartres. It specialises also in the experimental sciences. It is called the scientific traditionalism. Grosseteste (1175-1253) is the scientist who gave the physical theory of the universe. For him, light is a substance present everywhere and the first of all corporal forms.


            Roger Bacon (1210-1292) was a Franciscan and pupil of Grosseteste in Oxford. He went to Paris to learn from Alexander of Hales, suffered from the Hierarchy for suspicions of heresies, was condemned to prison in 1278, released in 1292. He is a contrasting personality. He poses as a detractor of scholasticism but follows it in its essential principles; he exalts the experimental science but defends the Augustinian illuminism; he studies nature but proclaims the supremacy of the mystical theology.  His fundamental pple is the theory of the unity of knowledge, the reduction of all arts to theology.


1.    The natures. All natures are composed of matter and form (absolute hylomorphism). Since he sees that reality is individual and that the ideas expressing it are universal, he conceives  each concrete corporal substance as a composite of different levels superimposed of so many forms which correspond to the concepts (corporeity, vegetative life, sensitive life, intellectual life). Prime Matter is not pure potency. It contains the seminal reasons. It varies accdg to the species ‘Ideo asinus non differt ab equo per solam formam sed per materiam aliam specificam.’


2.    Knowledge follows this conception of individual substances. There are two types of knowledge : experimental or global/concrete, and intellectual with direct intuitions of the substantial levels. Thus, there is no need of abstraction or of the agent intellect. For him, this Agent Intellect is God, who illumines all intelligences to give them knowl of the eternal truths.


3.    Experience. There are three sources of knowledge : authority, reason and experience. But authority wo reason is superstition. Reason alone knows nothing if it does not know Mathematics.[6] But Maths itself rests on experience. Thus, only experience is constitutive of science. There are two types of exp. corresponding to two intuitive types of knowledge : the external intuition and exp. of the external senses which is the source of the positive sciences; the internal intuition of truth, which is either natural or sn of theology or of the mystical intuitions.

Thus, Bacon joins all knowl and experience and orders them accdg to the Augustinian spirit.


[1] He wrote an extensive number of works (mostly phil. and theol). In his last sojourn in Paris, he wrote the equivalent of 8.000 pages yearly.

[2] In the Court of Urban IV, he meets G. de Moerbeke, and with his translations of Ar., he gives birth to his main philosophical commentaries between 1265-1268. These commentaries are the edition of Ar. expurged from Averroism and ‘baptised’ as the Pope requested it, bec. he separates the errors introduced by the Arab commentators, and interprets Ar. in the light of the faith, explaining what is obscure in matters of faith and correcting it by the principles of Aristotle himself.

[3] He is not synthetic in the way Descartes will be, following the system of mathematical deduction in straight line from a unique principle. For ST, the synthesis consists in uniting towards its epicentre a multiplicity of rays, and thus, he preserves and interprets the complexity of reality. Perhaps it is difficult to notice the relation between remote conclusions, but it is always easy to notice their relation with the central nucleous.

[4] CG II, xcviii everything is intelligible by  its being.

[5] Vs. Plato who considered esse as the undetermined.

[6] Earthly things are related to the planets the knowledge of which supposes Maths. And the nat. phenomena are directed by mathematical laws.

[7] He attributes to the ideas the formal extrinsic causality (ie. exemplary cause) as well as the efficient causality (cause by participation).