RAGIONE
Term used in philosophy which, especially in the sense of a faculty (*v.*), has had in the history of Western thought a multiplicity of meanings that have often given rise to misunderstandings and misconceptions. The term *ratio* probably derives from *ratus*, a participle of *reor* (to believe, to think), and before its properly philosophical use it meant calculation, relationship. *Ratio* corresponds both to *νοῦς* (Plato) and to *λόγος*, with this difference: *νοῦς* properly is the faculty or activity, while *λόγος* is the content of *νοῦς* (truth) or what *ratio* constructs (discourse, the sum of relationships, etc.). It is advisable to distinguish the two fundamental meanings of the term: *ratio* as faculty (*Vernunft*) and *ratio* as object of knowledge (*Grund*).
### I. *Ratio* as Faculty
The two terms *νοῦς* and *λόγος* together adequately express the sense of *ratio* as discursive or reasoning faculty, capable of formulating proofs, combining concepts and propositions, and providing demonstrations. In this function it is considered proper to man (who, according to Aristotle’s celebrated expression, is a *ζῷον λογικόν*), as St Thomas says (*In III Sent.*, dist. 25, q. 1, a. 1): «nor does it belong to God or to angels». In this sense it is distinguished from the intellect (*v.*), which is an intuitive activity, a grasping of being and capable of seizing first principles and the primary necessary truths of thought and life. These are not two distinct faculties, as St Augustine and St Thomas both agree. Indeed, for St Augustine, *ratio* and intellect (or *intelligentia*) inhere naturally in the mind (*De civ. Dei*, XI, ch. 2); the intellect is superior to *ratio* (*In Joann. Evang.*, tract. XV, 4, 19; and St Thomas, *Sum. Theol.*, II-II, q. 45, a. 5 ad 3), inasmuch as it is an interior vision (by which the mind perceives truth, which divine light reveals to it), the principle of understanding and the true eye of the soul (*De ordine*, II, ch. 2, n. 5; ch. 9, n. 26).
*Ratio*, on the other hand, is the *aspectus animi*, an organ of inquiry that discerns (analysis) and connects (synthesis), that is, the discursive faculty that applies itself to what is beneath it and to sensibles in order to judge (*De vera relig.*, ch. 29, n. 30). Even for Spinoza (*v.*) *ratio* is inferior to intuitive science: the former lets us see things sub quadam aeternitatis specie, the latter sub specie aeternitatis. Kant (*v.*) distinguishes between *ratio* (*Vernunft*)—the faculty that enables us to know the principles of a priori knowledge—and pure reason, the faculty that contains the principles that allow us to know something exclusively a priori (*Critique of Pure Reason*, Introduction, § VII); between theoretical or speculative reason, which applies itself to pure knowing and founds and constructs science, and practical reason, which contains the a priori principle of action or the rule of morality. Moreover, Kant uses the term *ratio* in the special sense of the higher faculty of the three metaphysical ideas of soul, world, and God (*Critique of Pure Reason*, Transcendental Dialectic, I, 1, section 1). In this sense *ratio* (*Vernunft*) is not opposed to experience (as in the previous case), but is distinguished from and opposed to the intellect (*Verstand*).
Rosmini (*v.*), drawing on St Augustine and opposing Kantian transcendentalism, likewise distinguishes between *ratio* and intellect or the light of *ratio*: the former is «the faculty of applying the idea of being» which is intuited by the intellect (*Principi di scienza morale*, ch. 1, art. 1). The post-Kantians made of *ratio* the absolute, intuitive of all reality which identifies with it: for Jacobi (*v.*) it is the faculty of grasping the supersensible; for Schelling (*v.*) it is the absolute (*Darstellung meines Systems der Philosophie*, in *Sämtliche Werke*, VI, p. 113); for Hegel (*v.*) it is the certainty of being all reality, the universality and objectivity in itself and for itself of self-consciousness (*Encyclopedia*, § 437).
Still in the sense of faculty, *ratio* means to judge well or rightly, that is, by making good use of the rules of logic (*v.*), and it also indicates, in modern rationalism and in Kant, the system of a priori principles not dependent on experience; finally, it is used in opposition to faith (*v.*) and to revealed and suprarational truth (for these last three senses *v.* RATIONALISM).
### II. *Ratio* as Object of Knowledge
This is what explains something in a twofold sense: ontological, as for example «reason for being», the «why» that explains and demonstrates the *ratio* of a thing, the final and formal cause; and epistemological, that is, the argument by which an assertion is supported and justified. In the language of the Scholastics the *ratio* of a thing is its essence (*ratio intellecta* is the same concept considered objectively). It can also be used in a normative sense of justification: for example, in the expression «I have my reasons for acting or thinking thus», that is, the legitimate motives for acting and affirming in one way rather than another. In this sense the *ratio* of a proposition or thesis is what justifies and demonstrates it as objectively valid. Finally, the expression «being of *ratio*» is what has objective existence only in the mind (without this excluding that it may have a real foundation), such as, for example, relations, negations, etc.
Contemporary philosophy has strongly criticized *ratio* as object of knowledge both in the ontological sense (denial of final or formal cause) and in the epistemological sense: there are no arguments to demonstrate an assertion as necessary, since only «hypotheses» exist which are accepted (one or another) according as they prove more or less suitable to a given historical or practical situation (*v.* the entries IRRATIONALISM; NEOPOSITIVISM; PRAGMATISM, etc.).