Realism was a response to philosophical questions posed in different terms depending on the era. We can then distinguish three important periods in the history of philosophical realism, corresponding to three types of debates:
- Antiquity and the Middle Ages: Quarrel of Universals, from Plato to Ockham. Questions about reality are asked only for a particular domain of speech and thought, that of universals (categories or general concepts)
- Modern period: Issues related to scientific realism versus naïve realism, from Descartes to Kant. This period is marked by a debate between realism and anti-realism on the sciences (Copernicus, Galileo, Descartes) and on common sense (Cartesians, Locke, Berkeley, Hume, Kant) concerning their metaphysical scope.
- Contemporary period: Autonomous debate on scientific realism, from Comte to today. The debate concerning the ontological scope of thought takes place in philosophy of science and epistemology independently of metaphysical speculations and major philosophical systems.
In antiquity, realism is a position that is generally defended about certain categories of things, in combination with an antirealist or skeptical position concerning other categories of things. This combination of realism and anti-realism is ancient and goes back at least to Plato, who asserted both the existence of “Ideas” (eidos) or “essences” and the illusory character of individual sentient beings. Aristotle, also a realist about essences, moderates this position by maintaining that essences cannot exist separately from individual sentient beings. The atomists Democritus, Epicurus and Lucretius in particular, consider on the contrary that the appearances of phenomena are based on the combination of simple elements – atoms – which constitute the reality of the world.
The Neoplatonic philosopher and logician Porphyry of Tyre, in his Isagoge which is commented on by the medievals together with Aristotle’s Organon (set of logical treatises), will bequeath to scholastic philosophers and theologians the question of universals and their reality. Porphyry indeed writes:
“First of all, with regard to genera and species, the question is whether they are [I] subsistent realities in themselves or only [II] mere conceptions of the mind, and, in admitting that they are substantial realities, if they are [Ia1] corporeal or [Ia2] incorporeal, if, finally, they are [Ib1] separated or [Ib2] subsist only in sensible things and according to them. I will avoid talking about it. This is a very deep problem and one which requires a completely different and more extensive investigation.”
Middle Ages: Quarrel of Universals
The quarrel over universals designates in the first place the debate which opposed, in the middle and at the end of the Middle Ages (11th-15th century), the partisans of realism and nominalism. This dispute develops from the problem of universals, which can be formulated as follows:
Socrates is a man and Plato is a man. In these statements, the same thing is predicted of Socrates and Plato. What then is this thing that is predicated? Does it really exist?
Until the modern period, “universals” are those things which are predicated of several individuals, essentially corresponding to common nouns and verbs (“man”, “walk”, “white”, etc.).
Three responses have dominated the lore in this dispute:
- realism: universals are very real entities;
- nominalism: universals are just words or verbal expressions designating individuals;
- conceptualism: universals are concepts, in other words, properties that have no existence on their own
Guillaume de Champeaux speaks of man as a reality present entirely in each man at the same time (realism), but under the influence of Abelard, he will end up considering universals as simple similarities. Abelard takes up the old argument of Boethius: no reality can be said of several things, only names have this virtue. Abelard defends a conceptualist or moderately realistic position: the general terms designate not entities existing by themselves but properties which do not exist separately from the things which they characterize.
These positions have their origin in the opposition between Aristotle and Plato on Ideas: Plato being associated with realism, Aristotle with conceptualism and the Stoics with nominalism. The problem of universals is a debate between realism and anti-realism which is termed “regional”: it only concerns a specific domain of objects or thoughts. However, the quarrel of the universals touched on all the aspects of philosophy approached at the time as well as on theology.
According to the medievalist Alain de Libera, medieval realism supports, against nominalism and conceptualism, four theses:
- Universals are things (reism);
- We must distinguish universal, particular, singular;
- In preaching, it is a thing that is predicated of a thing, and not a term of another term;
- Language restores reality.
The problem of universals is still the subject of discussion today, mainly in the analytic tradition, but in a renewed philosophical context (new logic since Frege, new physics, etc.). The crisis of foundations in mathematics has revived the debate. The three positions held in relation to the ontological status of logico-mathematical contents correspond to the three medieval positions on universals, as Willard V. O. Quine reminds us. Gottlob Frege’s logicism is a realism or “concept platonism”, David Hilbert’s formalism is a nominalism, and the intuitionism of Luitzen Egbertus Jan Brouwer is a conceptualism.
In this debate, Quine first took the nominalist position by co-authoring Steps Toward a Constructive Nominalism with Nelson Goodman, then sided with conceptualism. Nelson Goodman, and more recently David K. Lewis, are renowned defenders of nominalism. David M. Armstrong is an ardent defender of realism about universals.
Middle Ages: Thomistic and Neo-Thomistic Realism
- For Platonic realism, universals are things and they exist ante rem (before singular things)
- For nominalism, universals are flatus vocis (simple vocal emissions), they exist post rem (they only serve to nominally designate singular things)
- For conceptualism, finally, universals exist in re (they are constructions of the mind abstracted from extra-mental things).
The philosopher and theologian Thomas Aquinas, however, supports the three propositions together. According to St. Thomas, universals exist both ante rem, that is, in the divine understanding before Creation, in re: in the created things that actualize them, and post rem: in the human mind that conceives them.
Realism, for the Thomists (philosophers and theologians claiming the thought of Thomas Aquinas) grants ontological priority to being over the way it is known. Thomistic realism is thus opposed to idealism for which it is the knowing subject, or the Self, which pre-exists the known being; but also to empiricism, which is generally considered a “deflationary” philosophy (reducing the number of existing entities). Deflationism, represented for example by William of Ockham in the Middle Ages or David Hume in modern times, is anti-realistic from an ontological point of view because it refuses to hypostasize or multiply entities without necessity, according to the well-known maxim of Ockham’s razor.
The Aristotelian-Thomist-inspired philosophers Jean-Pierre Lainé and Marie-France Lainé summarize the three ontological positions as follows:
“If it is true that the object of philosophy is, as we say, the being of all things, […] it is no less true that one cannot relate to it otherwise than by knowing it, whence a somewhat inevitable split between those who will give priority to being or reality, and those who, on the contrary, will give it to the subject who knows […]. The first attitude will be called realism, since it favors the real, and the second idealism (not forgetting its enemy brother, empiricism) since, on the contrary, it gives preference to the subject and its ideas.”
Both authors associate nominalism and skepticism with empiricism. According to nominalism, abstract entities do not exist, skepticism denies that we can reach any form of absolute reality with certainty, and empiricism explains that it is our sensations that are the most vivid and the most real, not our abstract ideas.
Thomistic realism maintains a position contrary to the preceding ones: abstract entities exist and structure things from within, they are more the object of knowledge than purely singular things (“science consists of a judgment bearing on the universals and necessary beings,” asserts Aristotle), and reality is knowable in itself, not necessarily constructed or distorted by our subjectivity.
Thomist realism would later be updated and developed rigorously by neothomists, in particular by Étienne Gilson in his two works Réalisme thomiste et critique de la connaissance et Le Réalisme méthodique. Another updating of Thomism will see the light of day in analytical philosophy with “analytical Thomism” whose main representatives are Anthony Kenny, Peter Geach and G. E. M. Anscombe.
(Includes texts from Wikipedia translated and adapted by Nicolae Sfetcu)