According to the teaching of our Lord, what is wrong with the world is precisely that it does not believe in God. Yet it is clear that the unbelief which he so bitterly deplored was not an intellectual persuasion of God’s non-existence. Those whom he rebuked for their lack of faith were not men who denied God with the top of their minds, but men who, while apparently incapable of doubting him with the top of their minds, lived as though he did not exist.

John Baillie, in Our Knowledge of God