Ephesians 4:18

The phrase ἐσκοτωμένοι τῇ διανοίᾳ (Eph. 4:18) presents a syntactic and semantic ambiguity. Grammatically, σκοτόω ("to darken") is a transitive verb that typically takes a direct object in the accusative—thus, "to darken the thinking" would ordinarily appear as τὴν διάνοιαν σκοτοῦν. However, here the noun διάνοια appears in the dative, raising the question of construction.

The dative is construed as (a) a dative of instrument or cause ("darkened by the thinking"), or (b) less precisely, a dative of sphere or reference ("darkened in thinking"), which is the more interpretive rendering, despite lacking an explicit preposition such as ἐν. The former reading is grammatically stricter—suggesting the διάνοια itself as the agent of obscuration—while the latter is semantically idiomatic, portraying the seat or domain of the impairment.