Passing from the province of Expression to the treatment of matter with its two departments of Invention and Arrangement, we find that here also Isokrates has his distinctive merits. As regards Invention—the art of discovering the available ¹ resources of a theme—Dionysios pronounces Isokrates equal to Lysias ² ; Quintilian praises not merely his facility but his effort to bring out the higher aspects of his subject ³ . In analysing the epideictic branch of Rhetoric, Aristotle notices one device as specially frequent in Isokrates—the use of the topic of comparison for the purpose of magnifying or extolling ⁴ ( αὔξησις). The Philippos will supply an instance;— in order to show that Philip of Macedon could easily conquer Asia, Isokrates points out that harder things were done with smaller means by Alkibiades, Konon, Dionysios and the younger Cyrus ⁵ . The author of the Essay on Sublimity blames Isokrates— and rightly—for a too constant and ostentatious effort to heighten rhetorically the greatness of his theme ⁶ . This effort is akin to the essentially epideictic spirit of all his work, the spirit which is always tending to transform advice, as in the Panegyrikos and Philippos, or apology, as in the Antidosis and De Bigis, into encomium ⁷ .

In Arrangement Isokrates is very clever. He is ⁸ generally said to have invented the fourfold division of the speech—used, however, before him by Lysias—with proem, narrative, proof, epilogue ⁹ ; but his distinctive skill lay in the management of a more complex system. According to Dionysios, the arrangement of Isokrates excels that of Lysias in two main points—in fineness of subdivision and in variety,—this variety arising either from new combinations within the subject itself or from the introduction of episodes not strictly proper to it ¹⁰ . The use of the latter is illustrated by a remark of Aristotle in regard to the opening of an epideictic speech. Here, he suggests, the speaker may take a hint from the flute-player. The flute-player preludes with anything that he can play effectively, and then knits this on to the keynote of his theme. So it is, says Aristotle, in the proem to the ‘Helen’ of Isokrates; the Eristics have nothing to do with Helen. ‘And here, even if the speaker pass into a foreign region ( ἐκτοπίσῃ), it is better than that the speech should be monotonous.’ The ‘episode’ on Agamemnon in the Panathenaikos (§§ 74—87) is a good instance.

One uniform type of structure may be recognised in all the best discourses of Isokrates. There is a leading idea—generally some large proposition about the affairs of Athens or of Greece—which is worked out on the principle of antithesis. Every contrast which it can yield is developed: but through all divisions and subdivisions the dominant idea is kept before the mind; and, at the close, the simplicity of the original proposition emerges from these intricate, yet never confused, antitheses in the simplicity of the conclusion. Take, for instance, the Panegyrikos. The leading idea is—A Greek war with Persia. ‘Greece’ is dealt with in Part I., ‘Persia’ in Part II. In Part I. Athens is contrasted with Sparta; the services of Athens to Greece are analysed as (1) civil, (2) military—and here, as in wars between Greeks or in wars between Greek and barbarian. Part II. shows that (1) Persia is open to attack while (2) Greece has every motive for attacking. Then the conclusion:—A Greek war with Persia is both just and expedient. It is this power of dealing luminously with a large array of facts grouped round a central idea which Hermogenes praises as the ‘distinctness’ of Isokrates ¹¹ . Like his moral bent towards subjects of practical moment and towards permanence of literary result, this faculty of arrangement set an example useful beyond the sphere of Rhetoric. It helped to show the historian how large masses of material might be wrought into a form at once clear and interesting ¹² .