Aristotle, Aquinas & Emergence

I was asked to write an article relating the teaching of Aquinas to contemporary science for the journal Scientia et Fides. I decided to use and further develop the material contained in my doctoral dissertation. I expanded my reinterpretation of the classical notion of emergence, with its emphasis on the role of downward causation, in terms of the fourfold notion of causation in Aristotle and Aquinas, and the theory of divine action offered by the latter. The PDF version of the article is available HERE.

Abstract of the article:

One of the main challenges of the nonreductionist approach to complex structures and phenomena in philosophy of biology is its defense of the plausibility of the theory of emergence and downward causation. The tension between remaining faithful to the rules of physicalism and physical causal closure, while defending the novelty and distinctiveness of emergents from their basal constituents, makes the argumentation of many proponents of emergentism lacking in coherency and precision. In this article I aim at answering the suggestion of several thinkers to redefine emergence and downward causation in terms of the broader Aristotelian view of causation. In addition, I further develop this interdisciplinary conversation to include theological implications of emergentism, analyzed in reference to Aquinas’ understanding of divine action in terms of the same fourfold division of causes—bringing thus natural science, philosophy, and theology into creative and fruitful dialogue.

Keywords: emergence; downward causation; hylomorphism; teleology; Aristotle; Aquinas.


Thomism and Evolution

I’m sharing the good news. My article on the thomistic response to the theory of evolution – that I have been working on for a long time – has been published today in an online version of the coming issue of Theology and Science. you can find link to the article and a pdf of the final draft on my profile on ACADEMIA.EDU and RESEARCHGATE.NET.

The paper is significant for two reasons.

First, I’m bringing in it my discovery of a preliminary definition of natural selection in Aquinas’ commentary on Aristotle’s Physics II, 8 (198b 29-32), that can be found in In Phys. II, lect. 12, par. 253.

Second, in the theological part of the paper I bring Aquinas’ Commentary on Sentences (In I Sent., dist. 44, I, 2, co.) where Thomas — in the context of divine action in the possible perfection of the universe — says explicitly about addition of new species (multae aliae species).

Thomistic Response to the Theory of Evolution: Aquinas on Natural Selection and the Perfection of the Universe


Neither Aristotle nor Aquinas assumes the reality of the evolution of species. Their systems of thought, however, remain open to the new data, offering an essential contribution to the ongoing debate between scientific, philosophical, and theological aspects of the theory of evolution. After discussing some key issues of substance metaphysics in its encounter with the theory of evolution (hylomorphism, transformism of species, teleology, chance, the principle of proportionate causation), I present a Thomistic response to its major hypotheses. Concerning the philosophy of Aquinas I trace what might be seen as a preliminary description of natural selection in his commentary on Aristotle’s Physics. Turning toward theology, besides addressing the topics that were referred to in the past—such as: Aquinas’ reading of Genesis, his account of creation as dependence in being, secondary and instrumental causality, and univocal/equivocal predication of God—I bring into discussion Thomas’ concept of the perfection of the universe, which has been virtually unused in this context.

Key Words: Aristotle; Aquinas; Natural selection; Chance; Divine causality; Evolution; Hylomorphism; Perfection of the Universe; Teleology

Aristotle & Evolution

I want to share the news about my latest publication – an article on Aristotle and evolution published in the proceedings of the 1st Virtual international Conference on the Dialogue between Science and Theology organized by RCDST of Ovidius University of Constanta, Romania.

An Aristotelian Account of Evolution and the Contemporary Philosophy of Biology

The article is also available HERE

Proceedings of the conference



The anti-reductionist character of the recent philosophy of biology and the dynamic development of the science of emergent properties prove that the time is ripe to reintroduce the thought of Aristotle, the first advocate of a “top-down” approach in life-sciences, back into the science/philosophy debate. His philosophy of nature provides profound insights particularly in the context of the contemporary science of evolution, which is still struggling with the questions of form (species), teleology, and the role of chance in evolutionary processes. However, although Aristotle is referenced in the evolutionary debate, a thorough analysis of his theory of hylomorphism and the classical principle of causality which he proposes is still needed in this exchange. Such is the main concern of the first part of the present article which shows Aristotle’s metaphysics of substance as an open system, ready to incorporate new hypothesis of modern and contemporary science. The second part begins with the historical exploration of the trajectory from Darwin to Darwinism regarded as a metaphysical position. This exploration leads to an inquiry into the central topics of the present debate in the philosophy of evolutionary biology. It shows that Aristotle’s understanding of species, teleology, and chance – in the context of his fourfold notion of causality – has a considerable explanatory power which may enhance our understanding of the nature of evolutionary processes. This fact may inspire, in turn, a retrieval of the classical theology of divine action, based on Aristotelian metaphysics, in the science/theology dialogue. The aim of the present article is to prepare a philosophical ground for such project.

Philosophy of Causation – Vol. 2 – Middle Ages

The second part of the written part of my Special Comprehensive Exam takes us back to the Middle Ages. It proves that by no means it was a dark age, and that the modern science has its important predecessors in those working in the field of natural philosophy at that time. My summary gives a small insight into the complexity  of their ideas, and the importance of the causal reflection in their explanations.

Causality in Middle Ages

The first important center of science and philosophy in Middle Ages was located in Oxford. Its main representatives followed the Pythagoreans and Plato, fostering mainly the mathematical component. They searched for explanations in mathematical terms, trying to relate them to Aristotle’s causality.

robert-grosseteste-1-sizedOne of the first thinkers of that school, Robert Grosseteste (ca. 1168-1253), who tried to emphasize both the role of mathematics and the indispensability of experience and experiments (“in thought if not in deed”), which are supposed to verify or falsify the outcomes of physics. But he did not present any procedure of verification. It is also doubtful that he made real experiments. He would value a demonstration involving all four causes, but he thought they should be somehow quantifiable and amenable to mathematical treatment. (He presents an analysis of four causes of thunder: 1) the formal cause is “rumbling sound in clouds,” 2) the material cause is “quenching of fire in cloud,” 3) the efficiency involved is described through the mechanism that produces the thunder (clouds, vapor, fire in air), 4) the final cause (according to Pythagoreans) is to terrify those detained in the infernal regions.)

download=176443-Cook_Roger-BaconRoger Bacon (ca. 1214-1294) was a disciple of Grosseteste. He claims that mathematics is not only essential for understanding all sciences. Without it we are not able to understand the world. Although, following his teacher, he states that mathematical reasoning must be supplemented by experience to make its intuitions certain, it is again questionable whether he performed real experiments. But it needs to be noticed that he, supported by John Peckham (ca. 1230-1292), brought an important contribution to optical sciences (even if their appeal was more towards experience than experimentation). They were also committed to a realist philosophy of science and were looking for causes of phenomena.

William_of_OckhamThe 14th century science at Oxford further questioned realism and remained under the influence of the nominalism of William of Ockham (ca. 1287-1347), who would challenge the reality of Aristotelian “common natures.” Terms such as quantity, motion, time, space, velocity and causality, had for him no other real referents than an individual substance. In this situation only the mathematical approach was able to survive (it developed analyses similar to those employed in 17th century science), while the experimental and causal components were somehow neglected. This turn brought a development of calculatory techniques and kinetics. Indeed, it was the Medieval Oxford where an important development of the philosophy of motion was reached by a series of thinkers such as: Ockham, who associated motion with successive positions of body in motion (res relativa, forma fluens); Walter Burley (ca. 1275-1344), for whom motion was res successiva, that is something real, over and above moving object, having its causes and effects (not only forma fluens but also fluxus forme); Thomas Bradwardine (ca. 1290-1349), who equated motion with “speed of motion,” and thus brought a mathematization of motion; William Heytesbury (before 1313-1372/73), who introduced important kinematical rules called “mean-speed theorem;” and Richard Swineshead (fl. ca. 1340-1354), who is associated with an anonymous Tractatus de motu locali difformi, in which we find a description of four causes of local motion: “the material cause of motion, or the matter of motion, is whatever is acquired through motion; the formal cause is a certain transmutation conjoined with time; the efficient cause is a ratio of greater inequality of the moving power over resistance; and the final cause is the goal intended.”

The other center of medieval philosophy and science was located in Paris and remained in an opposition to Oxford. Its main thinkers did not trust mathematics as much as the empirical temper of Aristotelian tradition (rediscovered at the University of Paris). They believed in man’s ability both to come to know the world of nature and to discover and name the causes of its phenomena. Thus, it was the academia in Paris that gave start to the reflection on dynamical problems, supporting the origin of a systematic science of mechanics, which already had its kinematic component established at Oxford.

AlbertusMagnusThe philosophical foundation of the Paris movement was offered by Albert the Great (1193/1206-1280) and his ingenious pupil Thomas Aquinas (1225?-1274). The first one of them, a leading scientist of his time, emphasized the role of observation and empirical reasoning. He saw the object of mathematics being an abstracted entity rather than an ontologically antecedent form. He emphasized the importance of the search for causes of natural things in the oft quoted passage from his De cello et mundo in which he says that: “In natural science we do not investigate how God the Creator operates according to His free will and uses miracles to show His power, but rather what may happen in natural things on the ground of the causes inherent in nature.”

Aquinas’ great contribution was his explanation of the way in which all four causes can be used in the demonstration in natural science. In his commentaries on major philosophical works of Aristotle Aquinas brings important development of the theory of four causes. He lists four types of formal causality, and introduces the distinction between essentia (essence, Aristotelian prime matter informed) and esse (existence). Following Avicenna, he defines four types of efficient causation and introduces important distinctions between principal/instrumental, and primary/secondary causes. He explains the way in which one thing can have many per se causes, cases of reciprocal causation, and those of things being causes of contrarieties. He also develops Aristotle’s reflection on the modes of causation, and provides an important commentary on Philosopher’s doctrine of necessity and chance. He shows that the problem of a chance event described in terms of two lines of causality crossing at a certain point of time and space cannot be resolved by tracing back each line of causality. Such operation will not provide an answer to the question of the proper (per se) cause of a chance occurrence.[1]

Developments of philosophy of causation presented by Albert the Great and Thomas Aquinas encouraged others to embrace more consciously and ardently philosophical realism in their science. Peter of Maricourt (fl. 1269) was a great experimenter who named magnet’s poles after the celestial poles and developed a methodology of falsification. Theodoric of Freiburg (ca. 1250-1310) who was a Dominican Friar concentrated himself on the search for the causes of rainbows and radiant phenomena. Although he emphasized the importance of all four causes in scientific explanation, he concentrated mainly on material and efficient causes. In his study of rainbows, he made an attempt on duplicating natural processes under controlled conditions, and thus gave the foundation to laboratory experiments. He also challenged Aristotle proposing his own use of induction which brings him closer to the modern experimental method than anyone else at his time.

The condemnations of Aristotle of 1270 and 1277 in Paris gave a fresh impulse to construct new hypothetical schemata for “saving the phenomena.” This brought a new realist analysis of local motion, developed by Jean Buridan (ca. 1310-after 1358), who claimed that it is real and independent of the thing moved and the place, and spoke of a virtus derelicta (“force left behind”) which he called impetus; Albert of Saxony (ca. 1316-1390), who speculated on the doctrine of impetus and the cause of the acceleration of falling bodies; and Nicole Oresme who would address the same problems in his writings. Interestingly enough, all three of them sowed seeds of the Copernican revolution, saying that both the hypothesis of earth in rest and the one with earth in motion, save the phenomena (but they refused to develop the second opinion). Oresme was also the first to develop an analogy between the workings of a clock and the universe, the analogy which would return and become very powerful with the mechanical turn in science.

Middle Ages brought one more opinion on causality, which remained in a radical opposition to the developments proposed in Oxford and Paris. Medieval occasionalism, linked to kalām, which is a type of philosophizing in Islam, developed by Al-Ash‘arī (d. 935) and Al-Ghazālī (1058–1111), denied any kind of causation in creatures, attributing it to the only true agent, God. This position was opposed by Averroes and Aquinas who argued that it deprives natural things of the actions that belong to them.

This story shows the ways in which the philosophy of causation, which had its roots in antiquity, was developed in Middle Ages. This movement prepared the stage for the Renaissance and the origin of the classical science, philosophy, and methodology which brought a dramatic change in philosophy of causation and more generally in philosophy of nature and metaphysics. I will describe them in the third episode which will be coming soon. 🙂