Laudator Temporis Acti

Aristophanes, Wasps 190-191 (tr. Jeffrey Henderson):

LOVECLEON
Leave me alone, or we'll soon be fighting.
LOATHECLEON
Fighting about what?
LOVECLEON
The donkey's shadow!

Φιλοκλέων
εἰ μή μ᾽ ἐάσεθ᾽ ἥσυχον, μαχούμεθα.
Βδελυκλέων
περὶ τοῦ μαχεῖ νῷν δῆτα;
Φιλοκλέων
περὶ ὄνου σκιᾶς.

Liddell-Scott-Jones, s.v. ὄνος, explain περὶ ὄνου σκιᾶς as "for an ass's shadow, i.e. for a trifle."

"A donkey's shadow" is an ancient proverb ripe for modern revival. When I listen to contemporary debates about politics or religion, I am often tempted to say, "A donkey's shadow."

Renzo Tosi, Dicionário de Sentenças Latinas e Gregas, tr. Ivone Castilho Benedetti (São Paulo: Martins Fontes, 1996), pp. 230-231 (#488 = Περὶ ὄνου σκιᾶς), cites most of the ancient evidence for this proverb, including the following literary references.

Aristophanes, fragment 192 Kock = Comicorum Atticorum Fragmenta I, 437 (from Daedalus; I don't have access to Kassel-Austin, but I think this is their fragment 199; my translation):

What's the battle about now? About a donkey's shadow.

περὶ τοῦ γὰρ ὑμῖν ὁ πόλεμος νῦν ἐστι; περὶ ὄνου σκιᾶς

Sophocles, fragment 331 Radt (from the satyr play Celadion, my translation):

Whatever happens, this is all a donkey's shadow.

ὅσ' ἂν γένηται ταῦτα πάντ' ὄνου σκιά.

Plato, Phaedrus 260c (where some editors excise σκιᾶς = shadow), tr. H.N. Fowler:

Then when the orator who does not know what good and evil are undertakes to persuade a state which is equally ignorant, not by praising the "shadow of an ass" under the name of a horse, but by praising evil under the name of good, and having studied the opinions of the multitude persuades them to do evil instead of good, what harvest do you suppose his oratory will reap thereafter from the seed he has sown?

ὅταν οὖν ὁ ῥητορικὸς ἀγνοῶν ἀγαθὸν καὶ κακόν, λαβὼν πόλιν ὡσαύτως ἔχουσαν πείθῃ, μὴ περὶ ὄνου σκιᾶς ὡς ἵππου τὸν ἔπαινον ποιούμενος, ἀλλὰ περὶ κακοῦ ὡς ἀγαθοῦ, δόξας δὲ πλήθους μεμελετηκὼς πείσῃ κακὰ πράττειν ἀντ᾽ ἀγαθῶν, ποῖόν τιν᾽ ἂν οἴει μετὰ ταῦτα τὴν ῥητορικὴν;

Archippus (late 5th-early 4th century BC) wrote a comedy with the title ὄνου σκιά = a donkey's shadow. See Suda, omicron 400 Adler, who cites Aristotle's Didascaliae (fragment 625 Rose), and Zenobius 6.28, in E.L. von Leutsch and F.G. Schneidewin, Corpus Paroemiographorum Graecorum, Vol. I (Gottingen: Vandenhoeck & Ruprecht, 1839), pp. 169-170 (at 170, lines 18-19).

Lucian, Hermotimus 71 (tr. Augusta M. Campbell Davidson):

All philosophers are contending as it were for an ass's shadow.

ἀλλὰ πάντες, ὡς ἔπος εἰπεῖν, περὶ ὄνου σκιᾶς μάχονται οἱ φιλοσοφοῦντες.

Dio Chrysostom 34.48 (tr. H. Lamar Crosby):

And whether it is a question of Aegaeans quarrelling with you [Tarsians], or Apameans with men of Antioch, or, to go farther afield, Smyrnaeans with Ephesians, it is an ass's shadow, as the saying goes, over which they squabble; for the right to lead and to wield authority belongs to others.

καὶ εἴτε Αἰγαῖοι πρὸς ὑμᾶς εἴτε Ἀπαμεῖς πρὸς Ἀντιοχεῖς εἴτε ἐπὶ τῶν πορρωτέρω Σμυρναῖοι πρὸς Ἐφεσίους ἐρίζουσι, περὶ ὄνου σκιᾶς, φασί, διαφέρονται. τὸ γὰρ προεστάναι τε καὶ κρατεῖν ἄλλων ἐστίν.

Apuleius, The Golden Ass 9.42 (tr. W. Adlington, rev. S. Gaselee), conflates two Greek proverbs (ὄνου σκιά = a donkey's shadow and ὄνου παράκυψις = a donkey's peeping):

But I, that was an ass very curious and restless in my nature, when I heard so great a noise craned my neck and put my head out of a little window to learn what the stir and tumult did signify. It fortuned that one of the soldiers, spying about, perceived my shadow, whereupon he began to cry, saying that he had certainly seen me: then they were all glad and a great shouting arose, and they brought a ladder and came up into the chamber and pulled me down like a prisoner; and when they had found me, they doubted nothing of the gardener, but seeking about more narrowly, at length they found him couched in a chest. And so they brought out the poor gardener to the justices, who was committed immediately to prison, in order that he might suffer the pain of death; but they could never forbear laughing and jesting how I looked out from my window: from which, and from my shadow, is risen the common proverb of the peeping and shadow of an ass.

The ancient scholiasts, lexicographers, and paroemiographers offer another aetiology of "a donkey's shadow." Tosi gives many citations for the aetiology, but not Aesopica 460 Perry = 339 Halm and Pseudo-Plutarch, Lives of the Ten Orators 8.64-65 = Moralia 848a-b. Here is the story, from the Aesopica, in Laura Gibbs' translation:

They say that during an assembly in Athens, Demosthenes was prevented from making his speech, so he told the audience he wanted to say just a few words. When the audience had fallen silent, Demosthenes began his tale. 'It was summertime, and a young man had hired a donkey to take him from Athens to Megara. At midday, when the sun was blazing hot, the young man and the donkey's driver both wanted to sit in the donkey's shadow. They began to jostle one another, fighting for the spot in the shade. The driver maintained that the man had rented the donkey but not his shadow, while the young man claimed that he had rented both the donkey and all the rights thereto.' Having told this much of the story, Demosthenes then turned his back on the audience and began to walk away. The Athenians shouted at him to stop and begged him to finish the story. 'Indeed!' said Demosthenes. 'You want to hear all about the donkey's shadow, but you refuse to pay attention when someone talks to you about serious matters!'

In the modern retelling of this tale by Christoph Martin Wieland (1733–1813) in Die Abderiten, Book IV: Der Process um des Esels Schatten, the name of the man who rented the donkey is Struthion, and the name of the donkey's owner is Anthrax.

Also not cited by Tosi is Origen, Against Celsus 3.1 (quoting Celsus; cf. also 3.2 and 3.4; tr. Frederick Crombie):

He gives it as his opinion, that "the controversy between Jews and Christians is a most foolish one," and asserts that "the discussions which we have with each other regarding Christ differ in no respect from what is called in the proverb, 'a fight about the shadow of an ass,'" and thinks that "there is nothing of importance in the investigations of the Jews and Christians: for both believe that it was predicted by the Divine Spirit that one was to come as a Saviour to the human race, but do not yet agree on the point whether the person predicted has actually come or not."

José Sánchez Lasso de la Vega, "Notulae," Emérita 38 (1960) 125–142, discusses the proverb on pp. 133–135, with the unconvincing suggestion that behind the expression is περὶ ὀνείρου σκιᾶς = concerning a dream's shadow.

I haven't seen Herwig Maehler, "Der Streit um den Schatten des Esels," in A.H.S. El-Mosalamy, ed., Proceedings of the XIXth International Congress of Papyrology, vol. I (Cairo, 1992), pp. 625-633 (discussing P.Berol. 21188 recto).

For more ancient lore and proverbs about donkeys, see Herbert Pierrepont Houghton, Moral Significance of Animals as Indicated in Greek Proverbs (Amherst: Carpenter & Morehouse, 1915 = diss. Johns Hopkins University), pp. 44-48, and Kathleen Freeman, "Vincent, or the Donkey," Greece & Rome  14, No. 41/42 (Jun., 1945) 33-41.

Thanks to Eric Thomson for much help with this post.