Sometimes those who are skeptical of the Natural vs. Moral Ability distinction are so because they do not believe it gives enough credence to the noetic effects of sin (the disabling effects of sin upon the mind), as is argued in Charles Hodge’s critique.  Owen, however, ‘the Prince of the Puritans’, recognizes the full weight of the noetic effects of sin (that it consists in a moral ‘deprivation of the light and power’ of the faculties) while still maintaining, in a different sense, that man has by his creaturely nature a natural, facultative capacity to receive spiritual things.  While man has a full facultative capacity to do all that God requires of him, according to Owen, he has no active moral power to do the spiritual things that God requires of him. 

John Owen on Natural vs. Moral Ability