But though Plato may have commenced at the age of twenty his acquaintance with Sokrates, he cannot have been exclusively occupied in philosophical pursuits between the nineteenth and the twenty-fifth year of his age — that is, between 409-403 B.C. He was carried, partly by his own dispositions, to other matters besides philosophy; and even if such dispositions had not existed, the exigencies of the time pressed upon him imperatively as an Athenian citizen. Even under ordinary circumstances, a young Athenian of eighteen years of age, as soon as he was enrolled on the public register of citizens, was required to take the memorable military oath in the chapel of Aglaurus, and to serve on active duty, constant or nearly constant, for two years, in various posts throughout Attica, for the defence of the country.[9] But the six years from 409-403 B.C. were years of an extraordinary character. They included the most strenuous public efforts, the severest suffering, and the gravest political revolution, that had ever occurred at Athens. Every Athenian citizen was of necessity put upon constant (almost daily) military service; either abroad, or in Attica against the Lacedæmonian garrison established in the permanent fortified post of Dekeleia, within sight of the Athenian Akropolis. So habitually were the citizens obliged to be on guard, that Athens, according to Thucydides,[10] became a military post rather than a city. It is probable that Plato, by his family and its place on the census, belonged to the Athenian Hippeis or Horsemen, who were in constant employment for the defence of the territory. But at any rate, either on horseback, or on foot, or on shipboard, a robust young citizen like Plato, whose military age commenced in 409, must have borne his fair share in this hard but indispensable duty. In the desperate emergency, which preceded the battle of Arginusæ (406 B.C.), the Athenians put to sea in thirty days a fleet of 110 triremes for the relief of Mitylenê; all the men of military age, freemen, and slaves, embarking.[11] We can hardly imagine that at such a season Plato can have wished to decline service: even if he had wished it, the Strategi would not have permitted him. Assuming that he remained at home, the garrison-duty at Athens must have been doubled on account of the number of departures. After the crushing defeat of the Athenians at Ægospotami, came the terrible apprehension at Athens, then the long blockade and famine of the city (wherein many died of hunger); next the tyranny of the Thirty, who among their other oppressions made war upon all free speech, and silenced even the voice of Sokrates: then the gallant combat of Thrasybulus followed by the intervention of the Lacedæmonians — contingencies full of uncertainty and terror, but ending in the restoration of the democracy. After such restoration, there followed all the anxieties, perils, of reaction, new enactments and provisions, required for the revived democracy, during the four years between the expulsion of the Thirty and the death of Sokrates.
[9] Read the oath sworn by the Ephêbi in Pollux viii. 105. Æschines tells us that he served his two ephebic years as περίπολος τῆς χώρας, when there was no remarkable danger or foreign pressure. See Æsch. De Fals. Legat. s. 178. See the facts about the Athenian Ephêbi brought together in a Dissertation by W. Dittenberger, p. 9-12.
[10] Thuc. vii. 27: ὁσημέραι ἐξελαυνόντων τῶν ἱππέων, &c. Cf., viii. 69. Antiphon, who is described in the beginning of the Parmenides, as devoted to ἱππικὴ, must have been either brother or uncle of Plato.
[11] Xen. Hell. i. 6, 24. Οἱ δὲ Ἀθηναῖοι, τὰ γεγενημένα καὶ τὴν πολιορκίαν ἐπεὶ ἤκουσαν, ἐψηφίσαντο βοηθεῖν ναυσὶν ἑκατὸν καὶ δέκα, εἰσβιβάζοντες τοὺς ἐν ἡλικίᾳ ὄντας ἅπαντας, καὶ δούλους καὶ ἐλευθέρους· καὶ πληρώσαντες τὰς δέκα καὶ ἑκατὸν ἐν τριάκοντα ἡμέραις, ἀπῆραν· εἰσέβησαν δὲ καὶ τῶν ἱππέων πολλοί. In one of the anecdotes given by Diogenes (iii. 24) Plato alludes to his own military service. Aristoxenus (Diog. L. iii. 8) said that Plato had been engaged thrice in military expeditions out of Attica: once to Tanagra, a second time to Corinth, a third time to Delium, where he distinguished himself. Aristoxenus must have had fair means of information, yet I do not know what to make of this statement. All the three places named are notorious for battles fought by Athens; nevertheless chronology utterly forbids the supposition that Plato could have been present either at the battle of Tanagra or at the battle of Delium. At the battle of Delium Sokrates was present, and is said to have distinguished himself: hence there is ground for suspecting some confusion between his name and that of Plato. It is however possible that there may have been, during the interval between 410-405 B.C., partial invasions of the frontiers of Bœotia by Athenian detachments: both Tanagra and Delium were on the Bœotian frontier. The great battle of Corinth took place in 394 B.C. Plato left Athens immediately after the death of Sokrates in 399 B.C., and visited several foreign countries during the years immediately following; but he may have been at Athens in 394 B.C., and may have served in the Athenian force at Corinth. See Mr. Clinton, Fast. Hell. ad ann. 395 B.C. I do not see how Plato could have been engaged in any battle of Delium after the battle of Corinth, for Athens was not then at war with the Bœotians.
At the same time I confess that the account given by or ascribed to Aristoxenus appears to me to have been founded on little positive information, when we compare it with the military duty which Plato must have done between 410-405 B.C.
It is curious that Antisthenes also is mentioned as having distinguished himself at the battle of Tanagra (Diog. vi. 1). The same remarks are applicable to him as have just been made upon Plato.
From the dangers, fatigues, and sufferings of such an historical decad, no Athenian citizen could escape, whatever might be his feeling towards the existing democracy, or however averse he might be to public employment by natural temper. But Plato was not thus averse, during the earlier years of his adult life. We know, from his own letters, that he then felt strongly the impulse of political ambition usual with young Athenians of good family;[12] though probably not with any such premature vehemence as his younger brother Glaukon, whose impatience Sokrates is reported to have so judiciously moderated.[13] Whether Plato ever spoke with success in the public assembly, we do not know: he is said to have been shy by nature, and his voice was thin and feeble, ill adapted for the Pnyx.[14] However, when the oligarchy of Thirty was established, after the capture and subjugation of Athens, Plato was not only relieved from the necessity of addressing the assembled people, but also obtained additional facilities for rising into political influence, through Kritias (his near relative) and Charmides, leading men among the new oligarchy. Plato affirms that he had always disapproved the antecedent democracy, and that he entered on the new scheme of government with full hope of seeing justice and wisdom predominant. He was soon undeceived. The government of the Thirty proved a sanguinary and rapacious tyranny,[15] filling him with disappointment and disgust. He was especially revolted by their treatment of Sokrates, whom they not only interdicted from continuing his habitual colloquy with young men,[16] but even tried to implicate in nefarious murders, by ordering him along with others to arrest Leon the Salaminian, one of their intended victims: an order which Sokrates, at the peril of his life, disobeyed.
[12] Plato, Epistol. vii. p. 324-325.
[13] Xen., Mem. iii. 6.