The god of this world is Paul's title for Satan in 2 Corinthians 4:4: in whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them. The title is provocative: it grants Satan the language of god (lower-case) precisely to expose his usurpation; the true God remains the Creator he opposes.
(2 Cor 4:4.) Paul's title for Satan; the false god of the present age, blinding unbelief.
Greek theos tou aiōnos toutou — the god of this age. The title is striking; it deliberately attributes to Satan the language reserved for God, exposing his usurped reign over fallen humanity.
His specific work: blinding the minds of them which believe not. Conversion is therefore an unblinding (2 Cor 4:6: God, who commanded the light to shine out of darkness, hath shined in our hearts).
2 Corinthians 4:4 — "In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ... should shine unto them."
John 12:31 — "Now is the judgment of this world: now shall the prince of this world be cast out."
John 14:30 — "The prince of this world cometh, and hath nothing in me."
1 John 5:19 — "The whole world lieth in wickedness."
Modern unbelief looks like a personal failure to think rightly; Paul names it as the work of a god blinding minds.
2 Corinthians 4:4 is uncomfortable for modern apologetics. Unbelief is not first an intellectual problem; it is a blinding of the mind by the god of this world. Argument alone will not unblind; God's shining of light into hearts will (2 Cor 4:6).
The household's evangelism therefore depends on prayer for the lifting of the blinding more than on cleverness of presentation. The Lord open her heart (Acts 16:14) is the actual mechanism; arguments are scaffolding around the same prayer.
Greek theos tou aiōnos toutou — the god of this age.
Greek theos — god (lower-case here, of the false god).
Greek aiōn — age, world; the present-age domain.
"Unbelief is mind-blinding before it is argument-failure."
"The Lord open her heart — the actual mechanism."
"Argument is scaffolding around prayer."