STOICISM. — Philosophical school founded in the “Stoa” (Portico) of Athens by Zeno of Citium around 300 B.C. His successors were Cleanthes (d. in 233–32), author of a famous hymn to Zeus, and Chrysippus of Soli (d. around 206). The Ancient Stoa also included Aristo of Chios, Eratosthenes of Cyrene, Zeno of Tarsus... Then came the Middle Stoa, whose principal centre was Rhodes: its most distinguished representatives were Boethus of Sidon (d. in 119 B.C.), Panaetius of Rhodes (180–110), and Posidonius of Apamea (135–51). With them, s. opened eclectically to the influence of Plato and Aristotle and, especially in the last of them, intensified the religious sense of speculation, Neoplatonism (v.). Panaetius’ work, Περὶ τοῦ καθήκοντος, would serve as the model for Cicero’s De officiis. The New Stoa, or Roman Stoa, of which Panaetius was the principal founder and which flourished in the imperial age, included L. A. Seneca (v.), Epictetus (v.), and the emperor Marcus Aurelius. With them, original s. lost much of its systematic rigour, indulging in not a few motifs of Platonic dualism. The same philosophical school founded at Rome by Q. Sextius around 40 B.C. may also be regarded as a derivation from s., even though Pythagorean influences are evident in it, especially in Sotion of Alexandria, Seneca’s teacher.
The Stoics divide philosophical investigation into the three fundamental parts, logic, physics, and ethics, while acknowledging their intrinsic connection and unity (Arnim, work cited in the bibliography, II, 38). In its physical conception, s., reacting decisively against Platonic and Aristotelian dualism, renews certain fundamental aspects of Heracliteanism monism (v.). The incorporeal does not exist; only bodies are substances, since only what is material acts and produces effects. The incorporeal are place, time, motion, and everything that “can be enunciated” (τὸ λεκτόν) of substance. Through a critical revision of Aristotelianism, the Stoics reduce the fundamental determinations of reality, or categories, to four: substance, quality, modality, and relation. Substance or substratum (οὐσία, ὑποκείμενο) is the prime matter of which everything is constituted; essential quality (τὸ ποιόν) is what differentiates substances and is inseparable from them; modality (πῶς ἔχον) is an accidental quality (such as being seated) that does not subsist in itself; relation (πρὸς τί πῶς ἔχον) exists only in relation to something else (such as right and left). The latter two, unlike the former two, are therefore not entities but merely incorporeal “enunciables.” There are two primordial principles of everything: the passive principle, which is substance devoid of quality, or matter, and the active principle (no less corporeal than the other), namely reason (λόγος), which produces individual beings within it and is inseparable from II. God is the logos, “industrious and artificer fire” (πῶς τεχνίτης), which informs matter from within; he is spirit (πνεῦμα), which pervades every living being and gives it unity and consistency; he is “like a seed (λόγος σπερματικός) that contains within itself all the reasons of the beings that were, are, and will be” (Aristocles, in Eusebius, Praep. ev., XV, 816 d), and is therefore providence (πρόνοια), necessity (ἀνάγκη), destiny (εἱμαρμένη), and the immanent principle of finality: of cohesion in the mineral world, of vegetative power in plants, of sensation in animals, and of reason in human beings. As such, God assumes many names; the gods, that is, the elements and natural phenomena, are born and die, but Zeus, the inextinguishable fire, endures through the changing vicissitudes of the world. Thus the Stoics interpret traditional mythology naturalistically. The cosmos is spherical and therefore finite (although the space surrounding it is infinite), animate, perfect, blessed, and divine: it is generated from fire and is resolved into fire in a general conflagration (ἐκπύρωσις; Seneca [Nat. quaest., III, 29] considers it of Babylonian origin), only to be reborn like the mythical phoenix and repeat exactly the preceding cycle (ἀποκατάστασις). The souls of human beings (only those of the best, according to Chrysippus) survive until the epyrosis, since the soul too is a corporeal breath innate in the human being.
Closely connected with the naturalistic principles is Stoic logic, which aims to be a logic of the concrete. Hostile to every form of innatist epistemology, the Stoics see sensory experience as the beginning of all knowledge: it begins with sensation, which is an impression (τύπωσις) of the object upon the soul, or, as Chrysippus maintained, an alteration (ἀλλοίωσις); once sensation has ceased, representation (φαντασία) arises; from the repetition of representations experience is formed, and from experience derives intellectual knowledge, or science, which is an organic connection of concepts. Of concepts, some are formed spontaneously in all human beings and are therefore called “anticipations” (προλήψεις) and “common notions” (κοινώ) (ἐννοίωσις); others, however, are the result of reflection and mental operations. Although sensation is a passivity (πάθος), the Stoics, unwilling to reduce knowledge to the mere recording of empirical data, highlight through the theory of “assent” (συγκατάθεσις) the active aspect of knowledge: there is no “apprehension” (κατάληψις) assent (v.). Here, however, the solutions are equivocal: sometimes assent conditions apprehension, in which case the intellectual act is the work of a free intervention by the subject and, as such, is distinct from sensation (the voluntarist thesis); at other times, apprehension is the presupposition of assent, insofar as sensation is considered already endowed with its own evidence (ἐνάργεια), that is, as a “cognitive impression” (φαντασία κατὰληπτική): the tendency is thus to unify sensation and intellect or, in any case, to minimize their distinction (the intellectualist thesis). In short, s., which has complete confidence in the value of perception, lacks a critical theory of experience. Consequently, criterion (v.) of truth was placed now in the “cognitive impression,” now in the “common notions,” and now in the “coherence” among representations. Once the world had been conceived as an organic and living being, pervaded inwardly by the divine unifying Force, knowledge too undoubtedly had to be conceived as a “relation” and as an “agreement” subject (v.) object (v.). This metaphysical dogma, while conferring upon particular things the unity and connection that seemed compromised by naturalistic premises, also led the Stoics to recognize a very special importance in hypothetical and disjunctive syllogisms, at the expense of apodictic knowledge—not so much in order to introduce an element of contingency (in any case antithetical to their determinism), as to adapt the movement of thought more closely to the various and manifold aspects of experience.
In ethics (manifestly open to the influences of Cynic thought), Stoicism reveals the most vital tendencies and, at the same time, the most critical aspects of the Hellenistic age. Its categorical imperative is perfectly consistent with its metaphysics: “Live according to nature”; naturam sequere. And since the world is governed by an unfailing law, that is, by the divine Logos, man—the only one among living beings capable of knowing that law and consciously accepting it—has the duty (τὸ καθήκον) of conforming to it: “Grande solacium est cum universo rapi” (Seneca, De prov., V, 8). Therefore, living in conformity with nature is equivalent to “following reason,” to “living consistently” (ὁμολογουμένως ἴζω); for the Logos is one and immutable. Stoic wisdom arises above all from this lyrical contemplation of the cosmos, experienced in a pantheistic sense, from this sympathetic relationship between the individual and the Whole: the lucid and immovable knowledge of the universal order is translated into disinterested actions that know no compromise with the passions. Now, the passions (which Zeno reduced to four fundamental ones: desire, pleasure, fear, and pain) are not the consequences of an irrational part of the soul, opposed by nature to the good (something Stoic pantheism cannot admit), but are disordered impulses of the soul, produced by false judgments of value and erroneous opinions. Virtue, the only true good, is therefore perfect reason, having attained the highest degree of knowledge; it is consequently also “apathy” (ἀπάθεια). All the virtues, having common principles and an identical end, are different names for one and the same fundamental virtue. And since virtue is one, whoever truly possesses one virtue possesses them all; and whoever possesses one vice possesses them all. There is no intermediate state between virtue and vice. Stoicism exalts the dignity of the sage, who rises free and imperturbable before reality, serenely and heroically enduring the blows of fortune. “Abstain and endure” (ἀνέγου καὶ ἀπέγου). For him, all those things are indifferent (ἀδιάφορα)—such as health, beauty, wealth, and glory—which are not in themselves either vices or virtues; even life is an ἀδιάφορον, from which the sage may free himself by suicide (ἔξαγωγή) in cases of extreme necessity (Marcus Aurelius, III, 1; Epictetus, Diss., I, 29, 29; Seneca, Ep., 80, 34-36; 70, 6.17). Yet this ethical rigorism was not always maintained within such narrow limits: indifferent things were themselves distinguished into “preferable” (προγγιένα), “non-preferable” (ἀποπρογγιένα), and “neutral”; between virtues and vices there came to be placed appropriate actions (πρέποντα), and eventually a “progress” in moral life was even admitted. Although egocentric and highly individualistic, Stoic ethics proclaimed the solidarity of all human beings; it affirmed a universal natural law that makes every human being a citizen of the world; it fought slavery and advocated the cosmopolitan ideal against the narrowness of nationalisms; under the impulse of its pantheistic monism, it polemicized against polytheistic religions and irrational cults, maintaining, on the basis of a consensus gentium, a universal primordial religiosity.
In the Roman world, Stoicism spread chiefly among the educated classes and, amid the general decline of traditional religion, constituted the nucleus of a more intimate and more firmly grounded ethical spirituality, shedding a considerable part of its logical and physical problems; its natural-law doctrine became the ideal basis for a theory of the Roman Empire understood as universal sovereignty. In this sense, its civilizing work stands alongside that of Christianity, with which it shares a soteriological interest and the cult of interiority. But the human dignity exalted by Stoicism does not naturalism (v.), nor is it strengthened in the light of operative charitas. In the history of thought, Stoic ethics has always been the standard of autonomy and inner self-sufficiency, influencing at times the Neoplatonists, at times the rationalists (Descartes, Spinoza), at times the moralists of the 16th and 17th centuries (Lipsius, Vossius, Heinsius, Charron), and at times Kantian thought. Its natural-law doctrine matured in Grotius into the requirements of an international law and LOCKE, JOHN (v.); its religious naturalism developed the concept of natural religion and also insinuated itself into the Reformation (Zwingli). The rigorous demand for immanent unity inspires all recurring forms of pantheism, as well as every cosmology understood teleologically; it incorporates the Orphic heritage, only to flow back in turn into Orphism (Orphic hymns); it nourishes Bruno’s heroic furors and his enthusiastic vision of the One-All; strangely intermingled with Neoplatonic motifs, it spreads through the Romantic milieu and lives again in Schelling’s pantheism and in the poetry of Goethe and Hölderlin. On the other hand, Stoic logic, as the logic of the particular and the concrete, in its effort to overcome Aristotelian difficulties without ever running nominalism (v.), deposits its experimentalist demands in modern empiricism (v.) (Bacon, Locke, Hume) positivism (v.), maintaining, no less than Epicureanism, the demand for concreteness and the polemic against essences in the name of functional relations.