Plato, Laws 638c

πῶς οὖν δὴ λέγεις; δοκοῦσί μοι πάντες οἱ λόγῳ τι λαβόντες ἐπιτήδευμα, καὶ προθέμενοι ψέγειν αὐτὸ ἢ ἐπαινεῖν εὐθὺς ῥηθέν, οὐδαμῶς δρᾶν κατὰ τρόπον, ἀλλὰ ταὐτὸν ποιεῖν οἷον εἰ δή τις, ἐπαινέσαντός τινος πυροὺς βρῶμα ὡς ἀγαθόν, εὐθὺς ψέγοι, μὴ διαπυθόμενος αὐτοῦ μήτε τὴν ἐργασίαν μήτε τὴν προσφοράν, ὅντινα τρόπον καὶ οἷστισι καὶ μεθʼ ὧν καὶ ὅπως ἔχοντα καὶ ὅπως προσφέρειν ἔχουσιν. νῦν δὴ ταὐτόν μοι

What is your account of it? In my opinion all those who take up an institution for discussion and propose, at its first mention, to censure it or commend it, are proceeding in quite the wrong way. Their action is like that of a man who, when he hears somebody praising cheese as a good food, at once starts to disparage it, without having learnt either its effects or its mode of administration—in what form it should be administered and by whom and with what accompaniments, and in what condition and to people in what condition.