The Pulpit Commentary on Proverbs 12:15

The way of a fool is right in his own eyes; i.e. in his own judgment (Proverbs 3:7 : Proverbs 16:2). The second clause is best translated, as in the Revised Version, "But he that is wise hearkeneth unto counsel," distrusting his own unaided judgment, which might lead him astray (Proverbs 13:10; Proverbs 14:12; Proverbs 16:25; Proverbs 21:2; comp. Ec 35:19; Tobit 4:18). Theognis, 221, etc.—

ὅς τις τοι δοκέει τὸν πλησίον ἴδμεναι οὐδὲν

ἀλλ αὐτὸς μοῦνος ποικίλα δήνε ἔχειν

κεῖνός γ ἄφρων ἐστὶ νόου βεβλαμμένος ἐσθλοῦ

ἴσως γὰρ πάντες ποικίλ ἐπιστάμεθα

"Who thinks his neighbour nothing knows,

And he alone can see,

Is but a fool, for we perhaps

Know even more than he."