Bibliography.—Historical: No complete history of logic in the sense in which it is to be distinguished from theoretical philosophy in general has as yet been written. The history of logic is indeed so little intelligible apart from constant reference to tendencies in philosophical development as a whole, that the historian, when he has made the requisite preparatory studies, inclines to essay the more ambitious task. Yet there are, of course, works devoted to the history of logic proper.
Of these Prantl’s Geschichte der Logik im Abendlande (4 vols., 1855-1870), which traces the rise, development and fortunes of the Aristotelian logic to the close of the middle ages, is monumental. Next in importance are the works of L. Rabus, Logik und Metaphysik, i. (1868) (pp. 123-242 historical, pp. 453-518 bibliographical, pp. 514 sqq. a section on apparatus for the study of the history of logic), Die neuesten Bestrebungen auf dem Gebiete der Logik bei den Deutschen (1880), Logik (1895), especially for later writers § 17. Ueberweg’s System der Logik und Geschichte der logischen Lehren (4th ed. and last revised by the author, 1874, though it has been reissued later, Eng. trans., 1871) is alone to be named with these. Harms’ posthumously published Geschichte der Logik (1881) (Die Philosophie in ihrer Geschichte, ii.) was completed by the author only so far as Leibnitz. Blakey’s Historical Sketch of Logic (1851), though, like all this writer’s works, closing with a bibliography of some pretensions, is now negligible. Franck, Esquisse d’une histoire de la logique (1838) is the chief French contribution to the subject as a whole.
Of contributions towards the history of special periods or schools of logical thought the list, from the opening chapters of Ramus’s Scholae Dialecticae (1569) downwards (v. Rabus loc. cit.) would be endless. What is of value in the earlier works has now been absorbed. The System der Logik (1828) of Bachmann (a Kantian logician of distinction) contains a historical survey (pp. 569-644), as does the Denklehre (1822) of van Calker (allied in thought to Fries) pp. 12 sqq.; Eberstein’s Geschichte der Logik und Metaphysik bei den Deutschen von Leibniz bis auf gegenwärtige Zeit (latest edition, 1799) is still of importance in regard to logicians of the school of Wolff and the origines of Kant’s logical thought. Hoffmann, the editor and disciple of von Baader, published Grundzüge einer Geschichte der Begriffe der Logik in Deutschland von Kant bis Baader (1851). Wallace’s prolegomena and notes to his Logic of Hegel (1874, revised and augmented 1892-1894) are of use for the history and terminology, as well as the theory. Riehl’s article entitled Logik in Die Kultur der Gegenwart, vi. 1. Systematische Philosophie (1907), is excellent, and touches on quite modern developments. Liard, Les Logiciens Anglais Contemporains (5th ed., 1907), deals only with the 19th-century inductive and formal-symbolic logicians down to Jevons, to whom the book was originally dedicated. Venn’s Symbolic Logic (1881) gave a careful history and bibliography of that development. The history of the more recent changes is as yet to be found only in the form of unshaped material in the pages of review and Jahresbericht.
1 Cf. Heidel, “The Logic of the Pre-Socratic Philosophy,” in Dewey’s Studies in Logical Theory (Chicago, 1903).
2 Heraclitus, Fragmm. 107 (Diels, Fragmente der Vorsokratiker) and 2, on which see Burnet, Early Greek Philosophy, p. 153 note (ed. 2).
3 e.g. Diog. Laërt. ix. 25, from the lost Sophistes of Aristotle.
4 Plato and Platonism, p. 24.
5 Nothing is. If anything is, it cannot be known. If anything is known it cannot be communicated.
6 Metaphys. μ. 1078b 28 sqq.
7 Cf. Arist. Top. θ. i. 1 ad fin.
8 For whom see Dümmler, Antisthenica (1882, reprinted in his Kleine Schriften, 1901).
9 Aristotle, Metaphys. 1024b 32 sqq.
10 Plato, Theaetetus, 201 E. sqq., where, however, Antisthenes is not named, and the reference to him is sometimes doubted. But cf. Aristotle, Met. H 3. 1043b 24-28.
11 Diog. Laërt. ii. 107.
12 Aristotle, An. Pr. i. 31, 46a 32 sqq.; cf. 91b 12 sqq.
13 Athenaeus ii. 59c. See Usener, Organisation der wissenschaftl. Arbeit (1884; reprinted in his Vorträge und Aufsätze, 1907).
14 Socrates’ reference of a discussion to its presuppositions (Xenophon, Mem. iv. 6, 13) is not relevant for the history of the terminology of induction.
15 Theaetetus, 186c.
16 Timaeus, 37a, b (quoted in H. F. Carlill’s translation of the Theaetetus, p. 60).
17 Theaetetus, 186d.
18 Sophistes, 253d.
19 Ib. id.; cf. Theaetetus, 197d.
20 Aristotle, de An. 430b 5, and generally iii. 2, iii. 5.
21 For Plato’s Logic, the controversies as to the genuineness of the dialogues may be treated summarily. The Theaetetus labours under no suspicion. The Sophistes is apparently matter for animadversion by Aristotle in the Metaphysics and elsewhere, but derives stronger support from the testimonies to the Politicus which presumes it. The Politicus and Philebus are guaranteed by the use made of them in Aristotle’s Ethics. The rejection of the Parmenides would involve the paradox of a nameless contemporary of Plato and Aristotle who was inferior as a metaphysician to neither. No other dialogue adds anything to the logical content of these.
Granted their genuineness, the relative dating of three of them is given, viz. Theaetetus, Sophistes and Politicus in the order named. The Philebus seems to presuppose Politicus, 283-284, but if this be an error, it will affect the logical theory not at all. There remains the Parmenides. It can scarcely be later than the Sophistes. The antinomies with which it concludes are more naturally taken as a prelude to the discussion of the Sophistes than as an unnecessary retreatment of the doctrine of the one and the many in a more negative form. It may well be earlier than the Theaetetus in its present form. The stylistic argument shows the Theaetetus relatively early. The maturity of its philosophic outlook tends to give it a place relatively advanced in the Platonic canon. To meet the problem here raised, the theory has been devised of an earlier and a later version. The first may have linked on to the series of Plato’s dialogues of search, and to put the Parmenides before it is impossible. The second, though it might still have preceded the Parmenides might equally well have followed the negative criticism of that dialogue, as the beginning of reconstruction. For Plato’s logic this question only has interest on account of the introduction of an Ἀριστοτέλης in a non-speaking part in the Parmenides. If this be pressed as suggesting that the philosopher Aristotle was already in full activity at the date of writing, it is of importance to know what Platonic dialogues were later than the début of his critical pupil.
On the stylistic argument as applied to Platonic controversies Janell’s Quaestiones Platonicae (1901) is important. On the whole question of genuineness and dates of the dialogues, H. Raeder, Platons philosophische Entwickelung (1905), gives an excellent conspectus of the views held and the grounds alleged. See also Plato.
22 E.g. that of essence and accident. Republic, 454.
23 E.g. the discussion of correlation, ib. 437 sqq.
24 Politicus, 285d.
25 Sophistes, 261c sqq.
26 E.g. in Nic. Eth. i. 6.
27 Philebus, 16d.
28 Principal edition still that of Waitz, with Latin commentary, (2 vols., 1844-1846). Among the innumerable writers who have thrown light upon Aristotle’s logical doctrine, St Hilaire, Trendelenburg, Ueberweg, Hamilton, Mansel, G. Grote may be named. There are, however, others of equal distinction. Reference to Prantl, op. cit., is indispensable. Zeller, Die philosophie der Griechen, ii. 2, “Aristoteles” (3rd ed., 1879), pp. 185-257 (there is an Eng. trans.), and Maier, Die Syllogistik des Aristoteles (2 vols., 1896, 1900) (some 900 pp.), are also of first-rate importance.
29 Sophist. Elench. 184, espec. b 1-3, but see Maier, loc. cit. i. 1.
30 References such as 18b 12 are the result of subsequent editing and prove nothing. See, however, Aristotle.
31 Adrastus is said to have called them πρὸ τῶν τοπικῶν.
32 Metaphys. E. 1.
33 De Part. Animal. A. 1, 639a 1 sqq.; cf. Metaphys. 1005b 2 sqq.
34 De Interpretatione 16a sqq.
35 De Interpretatione 16a 24-25.
36 Ib. 18a 28 sqq.
37 Ib. 19a 28-29.
38 As shown e.g. by the way in which the relativity of sense and the object of sense is conceived, 7b 35-37.
39 Topics 101a 27 and 36-b 4.
40 Topics 100.
41 Politics 1282a 1 sqq.
42 103b 21.
43 Topics 160a 37-b 5.
44 This is the explanation of the formal definition of induction, Prior Analytics, ii. 23, 68b 15 sqq.
45 25b 36.
46 Prior Analytics, i. 1. 24a 18-20, Συλλογισμὸς δὲ ἑστὶ λόγος ἐν ᾦ τεθέντων τινῶν ἕτερόν τι τῶν κειμένων ἐξ ἀνάγκης σνμβαίνει τῷ ταῦτα εἶναι. The equivalent previously in Topics 100a 25 sqq.
47 Prior Analytics, ii. 21; Posterior Analytics, i. 1.
48 67a 33-37, μὴ συνθεωρῶν τὸ καθ᾽ ἑκάτερον.
49 67a 39-63.
50 79a 4-5.
51 24b 10-11.
52 Posterior Analytics, i. 4 καθ᾽ αὐτὸ means (1) contained in the definition of the subject; (2) having the subject contained in its definition, as being an alternative determination of the subject, crooked, e.g. is per se of line; (3) self-subsistent; (4) connected with the subject as consequent to ground. Its needs stricter determination therefore.
53 73b 26 sqq., 74a 37 sqq.
54 90b 16.
55 Metaphys. Z. 12, H. 6 ground this formula metaphysically.
56 94a 12, 75b 32.
57 90a 6. Cf. Ueberweg, System der Logik, § 101.
58 78a 30 sqq.
59 Topics, 101b 18, 19.
60 Posterior Analytics, ii. 13.
61 Posterior Analytics, ii. 16.
62 Posterior Analytics, i. 13 ad. fin., and i. 27. The form which a mathematical science treats as relatively self-subsistent is certainly not the constitutive idea.
63 Posterior Analytics, i. 3.
64 Posterior Analytics, ii. 19.
65 De Anima, 428b 18, 19.
66 Prior Analytics, i. 30, 46a 18.
67 Topics, 100b 20, 21.
68 Topics, 101a 25, 36-37, b1-4, &c.
69 Zeller (loc. cit. p. 194), who puts this formula in order to reject it.
70 Metaphys. Δ 1, 1013a 14.
71 Posterior Analytics, 72a 16 seq.
72 Posterior Analytics, 77a 26, 76a 37 sqq.
73 Metaphys. Γ.
74 Posterior Analytics, ii. 19.
75 de Anima, iii. 4-6.
76 Metaphys. M. 1087a 10-12; Zeller loc. cit. 304 sqq.; McLeod Innes, The Universal and Particular in Aristotle’s Theory of Knowledge (1886).
77 Topics, 105a 13.
78 Metaphys. 995a 8.
79 E.g., Topics, 108b 10, “to induce” the universal.
80 Posterior Analytics, ii. 19, 100b 3, 4.
81 Topics, i. 18, 108b 10.
82 Prior Analytics, ii. 23.
83 Παράδειγμα, Prior Analytics, ii. 24.
84 Sigwart, Logik, Eng. trans. vol. ii. p. 292 and elsewhere.
85 Ueberweg, System, § 127, with a ref. to de Partibus Animalium, 667a.
86 See 67a 17 ἐξ ἁπάντων τῶν ἀτόμων.
87 Ἐπιφορά. Ἐπι = “in” as in ἐπαγωγὴ, inductio, and -φορὰ = -ferentia, as in διαφορὰ, differentia.
88 Diog. Laërt. x. 33 seq.; Sext. Emp. Adv. Math. vii. 211.
89 Diog. Laërt. x. 87; cf. Lucretius, vi. 703 sq., v. 526 sqq. (ed. Munro).
90 Sextus Empiricus, Pyrrhon. Hypotyp. ii. 195, 196.
91 Sextus, op. cit. ii. 204.
92 Op. cit. iii. 17 sqq., and especially 28.
93 The point is raised by Aristotle, 95A.
94 See Jourdain, Recherches critiques sur l’âge et l’origine des traductions latines d’Aristote (1843).
95 See E. Cassirer, Das Erkenntnisproblem, i. 134 seq., and the justificatory excerpts, pp. 539 sqq.
96 See Riehl in Vierteljahrschr. f. wiss. Philos. (1893).
97 Bacon, Novum Organum, ii. 22, 23; cf. also Aristotle, Topics i. 12. 13, ii. 10. 11 (Stewart, ad Nic. Eth. 1139b 27) and Sextus Empiricus, Pyrr. Hypot. iii. 15.
98 Bacon’s Works, ed. Ellis and Spedding, iii. 164-165.
99 A notable formula of Bacon’s Novum Organum ii. 4 § 3 turns out, Valerius Terminus, cap. 11, to come from Aristotle, Post. An. i. 4 via Ramus. See Ellis in Bacon’s Works, iii. 203 sqq.
100 De Civitate Dei, xi. 26. “Certum est me esse, si fallor.”
101 Cf. Plato, Republic, 381E seq.
102 Elementa Philosophiæ, i. 3. 20, i. 6. 17 seq.
103 Hobbes, Elementa Philosophiæ, i. 1. 5.
104 Id. ib. i. 6. 16.
105 Id. ib. i. 4. 8; cf. Locke’s Essay of Human Understanding, iv. 17.
106 Id. Leviathan, i. 3.
107 Id. Elem. Philos. i. 6. 10.
108 Condillac, Langue des Calculs, p. 7.
109 Locke, Essay, iii. 3.
110 Id. ib. iv. 17.
111 Loc. cit. § 8.
112 Id. ib. iv. 4, §§ 6 sqq.
113 Berkeley, Of the Principles of Human Knowledge, § 142.
114 Hume, Treatise of Human Nature, i. 1. 7 (from Berkeley, op. cit., introd., §§ 15-16).
115 Essay, iv. 17, § 3.
116 Hume, Treatise of Human Nature, i. 3. 15.
117 Mill, Examination of Sir William Hamilton’s Philosophy, cap. 17.
118 Cf. Mill, Autobiography, p. 159. “I grappled at once with the problem of Induction, postponing that of Reasoning.” Ib. p. 182 (when he is preoccupied with syllogism), “I could make nothing satisfactory of Induction at this time.”
119 Autobiography, p. 181.
120 The insight, for instance, of F. H. Bradley’s criticism, Principles of Logic, II. ii. 3, is somewhat dimmed by a lack of sympathy due to extreme difference in the point of view adopted.
121 Bacon, Novum organum, i. 100.
122 Russell’s Philosophy of Leibnitz, capp. 1-5.
123 See especially remarks on the letter of M. Arnauld (Gerhardt’s edition of the philosophical works, ii. 37 sqq.).
124 Gerhardt, vi. 612, quoted by Russell, loc. cit., p. 19.
125 Ibid., ii. 62, Russell, p. 33.
126 Spinoza, ed. van Vloten and Land, i. 46 (Ethica, i. 11).
127 Nouveaux essais, iv. 2 § 9, 17 § 4 (Gerhardt v. 351, 460).
128 Critique of Judgment, Introd. § 2, ad. fin. (Werke, Berlin Academy edition, vol. v. p. 176, l. 10).
129 Kant’s Introduction to Logic and his Essay on the Mistaken Subtlety of the Four Figures, trans. T. K. Abbott (1885).
130 Loc. cit., p. 11.
131 Or antitheses. Kant follows, for example, a different line of cleavage between form and content from that developed between thought and the “given.” And these are not his only unresolved dualities, even in the Critique of Pure Reason. For the logical inquiry, however, it is permissible to ignore or reduce these differences.
The determination too of the sense in which Kant’s theory of knowledge involves an unresolved antithesis is for the logical purpose necessary so far only as it throws light upon his logic and his influence upon logical developments. Historically the question of the extent to which writers adopted the dualistic interpretation or one that had the like consequences is of greater importance.
It may be said summarily that Kant holds the antithesis between thought and “the given” to be unresolved and within the limits of theory of knowledge irreducible. The dove of thought falls lifeless if the resistant atmosphere of “the given” be withdrawn (Critique of Pure Reason, ed. 2 Introd. Kant’s Werke, ed. of the Prussian Academy, vol. iii. p. 32, ll. 10 sqq.). Nevertheless the thing-in-itself is a problematic conception and of a limiting or negative use merely. He “had woven,” according to an often quoted phrase of Goethe, “a certain sly element of irony into his method; ... he pointed as it were with a side gesture beyond the limits which he himself had drawn.” Thus (loc. cit. p. 46, ll. 8, 9) he declares that “there are two lineages united in human knowledge, which perhaps spring from a common stock, though to us unknown—namely sense and understanding.” Some indication of the way in which he would hypothetically and speculatively mitigate the antithesis is perhaps afforded by the reflection that the distinction of the mental and what appears as material is an external distinction in which the one appears outside to the other. “Yet what as thing-in-itself lies back of the phenomenon may perhaps not be so wholly disparate after all” (ib. p. 278, ll. 26 sqq.).
132 Critique of Judgment, Introd. § 2 (Werke, v., 276 ll. 9 sqq.); cf. Bernard’s “Prolegomena” to his translation of this, (pp. xxxviii. sqq.).
133 Die Logik, insbesondere die Analytik (Schleswig, 1825). August Detlev Christian Twesten (1789-1876), a Protestant theologian, succeeded Schleiermacher as professor in Berlin in 1835.
134 See Sir William Hamilton: The Philosophy of Perception, by J. Hutchison Stirling.
135 Hauptpunkte der Logik, 1808 (Werke, ed. Hartenstein, i. 465 sqq.), and specially Lehrbuch der Einleitung in die Philosophie (1813), and subsequently §§ 34 sqq. (Werke, i. 77 sqq.).
136 See Ueberweg, System of Logic and History of Logical Doctrines, § 34.
137 Drei Bücher der Logik, 1874 (E.T., 1884). The Book on Pure Logic follows in essentials the line of thought of an earlier work (1843).
138 Logic, Eng. trans. 35 ad. fin.
139 Logic, Introd. § ix.
140 For whom see Höffding, History of Modern Philosophy, Eng. trans., vol. ii. pp. 122 sqq.; invaluable for the logical methods of modern philosophers.
141 Wissenschaft der Logik (1812-1816), in course of revision at Hegel’s death in 1831 (Werke, vols. iii.-v.), and Encyklopädie der philosophischen Wissenschaften, i.; Die Logik (1817; 3rd ed., 1830); Werke, vol. vi., Eng. trans., Wallace (2nd ed., 1892).
142 The Principles of Logic (1883).
143 Logic, or The Morphology of Thought (2 vols., 1888).
144 Logic, Pref. pp. 6 seq.
145 Id. vol. ii. p. 4.
146 Logik (1873, 1889), Eng. trans. ii. 17.
147 Op. cit. ii. 289.
148 Introd. to Logic., trans. Abbott, p. 10.
149 Ueber Annahmen (1902, &c.).
150 Logik (1880, and in later editions).
151 Yet see Studies in Logic, by John Dewey and others (1903).
LOGOCYCLIC CURVE, STROPHOID or FOLIATE, a cubic curve generated by increasing or diminishing the radius vector of a variable point Q on a straight line AB by the distance QC of the point from the foot of the perpendicular drawn from the origin to the fixed line. The polar equation is r cos θ = a(1 ± sinθ), the upper sign referring to the case when the vector is increased, the lower when it is diminished. Both branches are included in the Cartesian equation (x2 + y2)(2a − x) = a2x, where a is the distance of the line from the origin. If we take for axes the fixed line and the perpendicular through the initial point, the equation takes the form y √(a − x) = x √(a + x). The curve resembles the folium of Descartes, and has a node between x = 0, x = a, and two branches asymptotic to the line x = 2a.
LOGOGRAPHI (λόγος, γράφω, writers of prose histories or tales), the name given by modern scholars to the Greek historiographers before Herodotus.1 Thucydides, however, applies the term to all his own predecessors, and it is therefore usual to make a distinction between the older and the younger logographers. Their representatives, with one exception, came from Ionia and its islands, which from their position were most favourably situated for the acquisition of knowledge concerning the distant countries of East and West. They wrote in the Ionic dialect, in what was called the unperiodic style, and preserved the poetic character of their epic model. Their criticism amounts to nothing more than a crude attempt to rationalize the current legends and traditions connected with the founding of cities, the genealogies of ruling families, and the manners and customs of individual peoples. Of scientific criticism there is no trace whatever. The first of these historians was probably Cadmus of Miletus (who lived, if at all, in the early part of the 6th century), the earliest writer of prose, author of a work on the founding of his native city and the colonization of Ionia (so Suïdas); Pherecydes of Leros, who died about 400, is generally considered the last. Mention may also be made of the following: Hecataeus of Miletus (550-476); Acusilaus of Argos,2 who paraphrased in prose (correcting the tradition where it seemed necessary) the genealogical works of Hesiod in the Ionic dialect; he confined his attention to the prehistoric period, and made no attempt at a real history; Charon of Lampsacus (c. 450), author of histories of Persia, Libya, and Ethiopia, of annals (ὦροι) of his native town with lists of the prytaneis and archons, and of the chronicles of Lacedaemonian kings; Xanthus of Sardis in Lydia (c. 450), author of a history of Lydia, one of the chief authorities used by Nicolaus of Damascus (fl. during the time of Augustus); Hellanicus of Mytilene; Stesimbrotus of Thasos, opponent of Pericles and reputed author of a political pamphlet on Themistocles, Thucydides and Pericles; Hippys and Glaucus, both of Rhegium, the first the author of histories of Italy and Sicily, the second of a treatise on ancient poets and musicians, used by Harpocration and Plutarch; Damastes of Sigeum, pupil of Hellanicus, author of genealogies of the combatants before Troy (an ethnographic and statistical list), of short treatises on poets, sophists, and geographical subjects.
On the early Greek historians, see G. Busolt, Griechische Geschichte (1893), i. 147-153; C. Wachsmuth, Einleitung in das Studium der alten Geschichte (1895); A. Schäfer, Abriss der Quellenkunde der griechischen und römischen Geschichte (ed. H. Nissen, 1889); J. B. Bury, Ancient Greek Historians (1909), lecture i.; histories of Greek literature by Müller-Donaldson (ch. 18) and W. Mure (bk. iv. ch. 3), where the little that is known concerning the life and writings of the logographers is exhaustively discussed. The fragments will be found, with Latin notes, translation, prolegomena, and copious indexes, in C. W. Müller’s Fragmenta historicorum Graecorum (1841-1870).
See also Greece: History, Ancient (section, “Authorities”).
1 The word is also used of the writers of speeches for the use of the contending parties in the law courts, who were forbidden to employ advocates.
2 There is some doubt as to whether this Acusilaus was of Peloponnesian or Boeotian Argos. Possibly there were two of the name. For an example of the method of Acusilaus see Bury, op. cit. p. 19.
LOGOS λόγος, a common term in ancient philosophy and theology. It expresses the idea of an immanent reason in the world, and, under various modifications, is met with in Indian, Egyptian and Persian systems of thought. But the idea was developed mainly in Hellenic and Hebrew philosophy, and we may distinguish the following stages:
1. The Hellenic Logos.—To the Greek mind, which saw in the world a κόσμος (ordered whole), it was natural to regard the world as the product of reason, and reason as the ruling principle in the world. So we find a Logos doctrine more or less prominent from the dawn of Hellenic thought to its eclipse. It rises in the realm of physical speculation, passes over into the territory of ethics and theology, and makes its way through at least three well-defined stages. These are marked off by the names of Heraclitus of Ephesus, the Stoics and Philo.
It acquires its first importance in the theories of Heraclitus (6th century B.C.), who, trying to account for the aesthetic order of the visible universe, broke away to some extent from the purely physical conceptions of his predecessors and discerned at work in the cosmic process a λόγος analogous to the reasoning power in man. On the one hand the Logos is identified with γνώμη and connected with δίκη, which latter seems to have the function of correcting deviations from the eternal law that rules in things. On the other hand it is not positively distinguished either from the ethereal fire, or from the εἱμαρμένη and the ἀνάγκη according to which all things occur. Heraclitus holds that nothing material can be thought of without this Logos, but he does not conceive the Logos itself to be immaterial. Whether it is regarded as in any sense possessed of intelligence and consciousness is a question variously answered. But there is most to say for the negative. This Logos is not one above the world or prior to it, but in the world and inseparable from it. Man’s soul is a part of it. It is relation, therefore, as Schleiermacher expresses it, or reason, not speech or word. And it is objective, not subjective, reason. Like a law of nature, objective in the world, it gives order and regularity to the movement of things, and makes the system rational.1
The failure of Heraclitus to free himself entirely from the physical hypotheses of earlier times prevented his speculation from influencing his successors. With Anaxagoras a conception entered which gradually triumphed over that of Heraclitus, namely, the conception of a supreme, intellectual principle, not identified with the world but independent of it. This, however, was νοῦς, not Logos. In the Platonic and Aristotelian systems, too, the theory of ideas involved an absolute separation between the material world and the world of higher reality, and though the term Logos is found the conception is vague and undeveloped. With Plato the term selected for the expression of the principle to which the order visible in the universe is due is νοῦς or σοφία, not λόγος. It is in the pseudo-Platonic Epinomis that λόγος appears as a synonym for νοῦς. In Aristotle, again, the principle which sets all nature under the rule of thought, and directs it towards a rational end, is νοῦς, or the divine spirit itself; while λόγος is a term with many senses, used as more or less identical with a number of phrases, οὖ ἕνεκα, ἐνέργια, ἐντελέχεια, οὐσία, εἶδος, μορφή, &c.
In the reaction from Platonic dualism, however, the Logos doctrine reappears in great breadth. It is a capital element in the system of the Stoics. With their teleological views of the world they naturally predicated an active principle pervading it and determining it. This operative principle is called both Logos and God. It is conceived of as material, and is described in terms used equally of nature and of God. There is at the same time the special doctrine of the λόγος σπερματικός, the seminal Logos, or the law of generation in the world, the principle of the active reason working in dead matter. This parts into λόγοι σπερματικοί, which are akin, not to the Platonic ideas, but rather to the λόγοι ἔνυλοι of Aristotle. In man, too, there is a Logos which is his characteristic possession, and which is ἐνδιάθετος, as long as it is a thought resident within his breast, but προφορικός when it is expressed as a word. This distinction between Logos as ratio and Logos as oratio, so much used subsequently by Philo and the Christian fathers, had been so far anticipated by Aristotle’s distinction between the ἔξω λόγος and the λόγος ἐν τῇ ψυχῇ. It forms the point of attachment by which the Logos doctrine connected itself with Christianity. The Logos of the Stoics (q.v.) is a reason in the world gifted with intelligence, and analogous to the reason in man.
2. The Hebrew Logos.—In the later Judaism the earlier anthropomorphic conception of God and with it the sense of the divine nearness had been succeeded by a belief which placed God at a remote distance, severed from man and the world by a deep chasm. The old familiar name Yahweh became a secret; its place was taken by such general expressions as the Holy, the Almighty, the Majesty on High, the King of Kings, and also by the simple word “Heaven.” Instead of the once powerful confidence in the immediate presence of God there grew up a mass of speculation regarding on the one hand the distant future, on the other the distant past. Various attempts were made to bridge the gulf between God and man, including the angels, and a number of other hybrid forms of which it is hard to say whether they are personal beings or abstractions. The wisdom, the Shekinah or Glory, and the Spirit of God are intermediate beings of this kind, and even the Law came to be regarded as an independent spiritual entity. Among these conceptions that of the word of God had an important place, especially the creative word of Genesis i. Here as in the other cases we cannot always say whether the Word is regarded as a mere attribute or activity of God, or an independent being, though there is a clear tendency towards the latter. The ambiguity lies in the twofold purpose of these activities: (1) to establish communication with God; (2) to prevent direct connexion between God and the world. The word of the God of revelation is represented as the creative principle (e.g. Gen. i. 3; Psalm xxxiii. 6), as the executor of the divine judgments (Hosea vi. 5), as healing (Psalm cvii. 20), as possessed of almost personal qualities (Isaiah lv. 11; Psalm cxlvii. 15). Along with this comes the doctrine of the angel of Yahweh, the angel of the covenant, the angel of the presence, in whom God manifests Himself, and who is sometimes identified with Yahweh or Elohim (Gen. xvi. 11, 13; xxxii. 29-31; Exod. iii. 2; xiii. 21), sometimes distinguished from Him (Gen. xxii. 15, &c.; xxiv. 7; xxviii. 12, &c.), and sometimes presented in both aspects (Judges ii., vi.; Zech. i.). To this must be added the doctrine of Wisdom, given in the books of Job and Proverbs. At one time it is exhibited as an attribute of God (Prov. iii. 19). At another it is strongly personified, so as to become rather the creative thought of God than a quality (Prov. viii. 22). Again it is described as proceeding from God as the principle of creation and objective to Him. In these and kindred passages (Job xv. 7, &c.) it is on the way to become hypostatized.