RATIONCINATION
**RATIONCINATION** (from *ratio*, q.v.) is the act by which thought, on the basis of given propositions, facts, or judgments, proceeds to a new affirmation. In its broadest sense, *rationcinatio* is synonymous with inference and denotes the discourse or movement of reason in act (premises, *prototae*, *tae prototatae*) toward further judgments (conclusions) that are connected to the former by a relation of causal derivation. The logical nexus of derivation (the *consequens* in Scholastic terminology) is essential; hence, not every process of thought that occurs through chance or mere temporal succession can be called *rationcinatio*.
In traditional logic, *rationcinatio* stands alongside concept (q.v.) and judgment (q.v.) as the third fundamental activity of reason. St. Thomas Aquinas sees in it the distinctive character of human understanding, which is essentially analytical and progressive in time: *"Homines ad intelligibilem veritatem non statim perveniunt, et ideo rationales dicuntur"* (Sum. Theol., I, q. 79, art. 8, c.; cf. De verit., q. 15, art. 1). Nevertheless, the cognitive principle that understands (*intellectus*) and that reasons (*ratio*) is identical; the difference is merely functional. While the intellect denotes "pure apprehension of truth," it is proper to reason to engage in *discursus*, and not elsewhere, for it cannot be introduced into cognition (In *Anal. Post.*, I, lect. 1, n. 4; cf. Sum. Theol., loc. cit., and q. 85, art. 4). *Rationcinatio* is thus, in relation to the intellect, as "acquisition" to "possession," "becoming" to "being," "motion" to "rest." Analyzing this relationship, St. Thomas observes that just as motion is impossible without a fixed point of departure, so too *rationcinatio* presupposes certain truths or principles of immediate intuition (*intellectus principiorum*), from which it proceeds and to which it returns in the resolutive and demonstrative process of conclusions. *Ratio* thus finds in *intellectus* both its principle and its term: *"Intellectus invenitur rationis principium quantum ad viam inveniendi, terminus vero quantum ad viam iudicandi"* (De verit., q. 15, art. 1).
As inference, *rationcinatio* is an essentially active function of thought: not mere intuition of a given datum, but a process of inquiry (*"a certis ad incertorum indagationem nitens cogitatio"*; St. Augustine, *De immort. anim.*, cap. 1; PL 32, 1021 A). It is clear, however, that the intuitive moment is not absent from *rationcinatio*; indeed, it assumes more complex forms than in pure concept. *Rationcinatio* is accomplished through a precise noetic act in which a certain proposition B is seen to depend upon and derive from a preceding proposition or series of propositions A. *Rationcinatio* is thus the intuition-affirmation of judgments (relations among concepts) and of causal nexuses between judgments; it therefore involves multiple intuitive moments that render *rationcinatio* almost a synthesis of the other mental acts, thereby further attenuating the distinction between *intellectus* and *ratio*.
As inference, *rationcinatio* does not necessarily imply the discovery of new truths, as in the case of a proposition already known but derived (proved) from a principle that justifies or confirms it (e.g.: theft is evil because it is irreconcilable with social life, and society is a good for man). The novelty of *rationcinatio* (which is always present, otherwise one could not speak of true inference or rational process) often consists precisely in the proof: B was known as problematic; now it is seen in its connection with A, which is certain. *Rationcinatio* determines here the relation of derivation of B from A and thus attains a new certainty and evidence for B (even if B was already known by another path).
Regarding the various forms of inference (for which see *SILOGISMO*), the general division of *rationcinatio* into deduction (q.v.) and induction (q.v.) should be noted. While deduction verifies the type of formal inference that is logically necessary (to which the norm *"ex vero non sequitur nisi verum"* primarily refers: cf. Aristotle, *Anal. pr.*, II, cap. 2, 53b7), induction, which infers universal principles from particular truths, relies less on the logical structure of *rationcinatio* than on the intellectual intuition of the relation of particular facts to the ontological determination of universal nature. Yet it would be an arbitrary restriction to conceive *rationcinatio* solely as formal inference (cf. A. Lalande, op. cit. in bibl., p. 868), for induction also verifies an effective process and dialectic of thought. Conversely, the contrary assertion (cf. J. Stuart Mill, *A System of Logic*, II, cap. 3) that sees only in induction a true inference, in the sense of an extension of knowledge, is equally unjustified.
*Rationcinatio* as a process unfolding in time (and thus open to a true "progress" of knowledge; for Bosanquet, the denial of the temporal duration of inference is "the first and fatal error" [op. cit. in bibl., p. 41]) and as dialectical development is an essential form of rational thought. It functions, on the one hand, due to the fragmentary and analytical nature of human knowing, and on the other, due to the indefinite relations that bind together the object and contents of thought into a unity. A movement of knowledge toward unity, analysis toward synthesis, *rationcinatio* is the logical expression of the ontological organic unity of the real. It is thus the perfection and power of thought, which, while extending the domain of truth in breadth, simultaneously clarifies it in depth by determining the manifold internal relations of structure, necessity, and causality.
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