Those who would construct a moral system independent of God and His law distinguish between theological and philosophical sin. Philosophical sin is a morally bad act which violates the natural order of reason, not the Divine law. Theological sin is a transgression of the eternal law. Those who are of atheistic tendencies and contend for this distinction, either deny the existence of God or maintain that He exercises no providence in regard to human acts. This position is destructive of sin in the theological sense, as God and His law, reward and punishment, are done away with. Those who admit the existence of God, His law, human liberty and responsibility, and still contend for a distinction between philosophical and theological sin, maintain that in the present order of God’s providence there are morally bad acts, which, while violating the order of reason, are not offensive to God, and they base their contention on this that the sinner can be ignorant of the existence of God, or not actually think of Him and His law when he acts. Without the knowledge of God and consideration of Him, it is impossible to offend Him. This doctrine was censured as scandalous, temerarious, and erroneous by Alexander VIII (24 Aug., 1690) in his condemnation of the following proposition: “Philosophical or moral sin is a human act not in agreement with rational nature and right reason, theological and mortal sin is a free transgession of the Divine law. However grievous it may be, philosophical sin in one who is either ignorant of God or does not actually think of God, is indeed a grievous sin, but not an offense to God, nor a mortal sin dissolving friendship with God, nor worthy of eternal punishment” (Denzinger-Bannwart, 1290).
This proposition is condemned because it does not distinguish between vincible and invincible ignorance, and further supposes invincible ignorance of God to be sufficiently common, instead of only metaphysically possible, and because in the present dispensation of God’s providence we are clearly taught in Scripture that God will punish all evil coming from the free will of man (Romans 2:5-11). There is no morally bad act that does not include a transgression of Divine law. From the fact that an action is conceived of as morally evil it is conceived of as prohibited. A prohibition is unintelligible without the notion of some one prohibiting. The one prohibiting in this case and binding the conscience of man can be only God, Who alone has power over man’s free will and actions, so that from the fact that any act is perceived to be morally bad and prohibited by conscience, God and His law are perceived at least confusedly, and a wilful transgression of the dictate of conscience is necessarily also a transgression of God’s law. Cardinal de Lugo (De incarnat., disp. 5, lect. 3) admits the possibility of philosophical sin in those who are inculpably ignorant of God, but he holds that it does not actually occur, because in the present order of God’s providence there cannot be invincible ignorance of God and His law. This teaching does not necessarily fall under the condemnation of Alexander VIII, but it is commonly rejected by theologians for the reason that a dictate of conscience necessarily involves a knowledge of the Divine law as a principle of morality.