This entry represents well the difficulties faced by the Suda lexicographers (and us) in defining and illustrating such words over the 1700 years of their use in Greek. For Homer and Pindar the word was still rich with its novelty and potential as a concept and metaphor: for the craftsmanship of a skilled artisan (tau 375, tau 435); for the decisive moment when a spear touches the body of its victim or a racer hits the finish line or touches his prize (epsilon 3344). When Pericles, in the Funeral Speech reported by Thucydides, used it in one of these senses in a climactic clause, it was already open to misunderstanding by the intellectuals (including Thucydides), who saw it as the main threat to man's rational control of his destiny (to judge from Villard Leglay's lengthy analysis of its use in such circles, cf. de Romilly, pp. 174-76): "They [sc. these men fallen in battle], through their encounter with man’s brief moment of opportunity, at its greatest intensity, were freed from their reputation rather than from their duty" (kai\ di' e)laxi/stou kairou= tu/xhs a(/ma a)kmh=| th=s do/chs ma=llon h)\ tou= de/ous a)phlla/ghsan: Thuc. 2.42.4, web address 1). The “encounter with the right moment” was indeed probably a metaphor from sailing, where the helmsman, in a ticklish manoeuvre of attack or defense, had to hit the right moment to touch the rudder, as well as one in medicine for the right moment to intervene. The concept, over its long history, lost its relationship to the verb for hitting the mark (epsilon 1147, eta 286, tau 435) and the metaphors in which it was once used. Like the other three concepts in the clause, notably kairo/s (cf. Trédé in bibliography), its meaning had changed in important respects before the scholiast and the Suda contributor commented on it. Tyche had come and gone as a goddess. Christians rejected savagely the philosophical view that Tyche as Fortune in some way interfered with God's governance of the universe, as we see in the first (unattributable) quotation and in the one from Procopius; for them it might mean no more than a manner of life.
See also tau 1233 for the use in Sophocles, tau 1232 for the use in Polybius, with bibliographies.
[1] This first point about tyche or fortune as one of the governing powers of the universe agrees with Aristotle, Physics 196b5-7: "There are some people who think that chance (fortune) is a cause, but one unclear to human mind, since it is something divine and extremely demonic." Ps-Plutarch, On Fate 572A-B, likewise attributes to "certain ancients" the view that "chance is an unforeseeable and unclear cause for human reasoning."
[2] The point about tyche as a fo/ra e)c a)dh/lwn closely resembles the entry for Tyche in [Plato], Definitiones 411B, and may be from a similar Academic list (Souilhé 154-59 is in error to attribute the definition to the Stoics). The writer uses the categories in Aristotle for defining particular sorts of motion (fo/ra): po/qen; poi=; ('Whence? Where to?'). See Weiss's superb treatment of tyche in Aristotle, esp. on the hitting of kairo/s as the excellence of praxis (London edn., 130-31).
[3] This concluding remark (cf. epsiloniota 142), rejecting any part for Tyche in the governance of the universe, indicates that the passage is the work of a Christian writer.
[4] Adler's reference is Polybius 'fr.83b[is]', and indeed Büttner-Wobst gives there, under the lemma tu/xh, the immediately preceding phrase of the entry: "we Christians etc." As there can of course be no question that Polybius had anything to say about Christianity, something is missing (or otherwise faulty) at this point.
[5] From the scholia to Thucydides 2.42.4 (web address 1), on the climactic clause in a famous passage of Pericles' Funeral Oration where he praises soldiers of disreputable origin for redeeming themselves by their sacrifice in battle for their country. The whole section is cited by Dionysius of Halicarnassus (de Thuc. Idiom. 16.1-13) as an example of 'winding, convoluted and involved organisation of enthymemes,' and this particular clause (quoted at the beginning of these notes) was echoed in antiquity with various syntactic phrasings. The scholiast takes a(/ma a)kmh=| as governing tu/xhs in the sense 'in the extreme heat (acme, or critical moment; cf. alpha 904, alpha 905, alpha 906) of the war (when chance or providence is about to turn it decisively one way or the other);' cf. tu/xhs a)kmh/n (Constantine VII Porphyrogenitus, De Legat. 382.11-18) and e)n a)kmh=| eu)tuxi/as (Libanius, Decl. 28.1.4). In an earlier epoch, Cassius Dio echoes the proverbial clause of Pericles but uses e)n akmh=| as governing not tu/xhs but do/chs (66.18.5) and de/ous (40.26.2, "at the acme of his reputation" or "fear"); cf. Arrian, Anabasis 7.16.7. No wonder that there is a hot debate in modern scholarship. See bibliography on Thucydides below. I rest on the analogies provided by those who have studied the concepts in Thucydides' own time, notably Trédé and Villard, to conclude that a(/ma a)kmh=| is to be taken on its own, meaning 'at the very pinnacle' and separating two coherent phrases (going with each of them in the poetic construction known as a)po\ koinou=; cf. Herodian, De Figuris 94.5, 17, and Hermogenes, De Inventione 4.3.38): "because of encountering their brief moment of opportunity” (for the metaphor involved see above) and “they were freed from their reputation" (and perhaps expectations, both discussed earlier in the paragraph) "rather than from their duty to authority" (a concept well analysed by Edmunds). Pericles thus echoes the famous epitaph on the Spartan dead at Thermopylae, who lie there still "obedient to their commands." See the translation at the beginning of the notes, and cf. Sophocles, Electra 31; also Isocrates 2.33 and Hyperides fr. 116 Jensen, at alpha 904.
[6] Procopius, Anecdota [Secret History] 4.44-45 (cf. pi 2991), cf. History of the Wars of Justinian 8.12.34-35. This comment clearly relates to Polybius; cf. tau 1232.
[7] For this proverb, of the Euripos straits between Attica and Euboea, see also alpha 2536 and delta 674, with the same gloss; cf. D. Whitehead, Hypereides: the forensic speeches (Oxford 2000) 421-3.
[8] Perhaps from Symeon Magister Metaphrastes (so Adler), in a work such as his Lives of the Gospel writers John and Luke or his Annals.
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