"In Adam" another view

Catholics have seen the phrase "In Adam" to be a reference to the passing of sin through conception. But the idea man is only flesh is incorrect, man is also spirit and each spirit of man is a creation of God. The catholic view of original sin sees man only as a fleshly creature, procreated in body and spirit.

We do not receive our spirits from Adam.

Zec 12:1 The burden of the word of the LORD for Israel, saith the LORD, which stretcheth forth the heavens, and layeth the foundation of the earth, and formeth the spirit of man within him.

Therefore the spirit of man Is created by God, pure. In this truth original sin doctrine falls apart.

Job 32:8 But there is a spirit in man: and the inspiration of the Almighty giveth them understanding.

So, Catholics have incorrectly argued "In Adam" is a reference to fleshly pro-creation. That is why they believe original sin is passed through the flesh.

"In Adam" and "In Christ" are similar phrases, we know that "In Christ" is not speaking of physical procreation, for it must be through the New Birth. So why see "In Adam" as a physical concept?

1Co 15:22 For as in Adam all die, even so in Christ shall all be made alive.

Matthew Henry in his Commentary on John 3 saw death as losing our godly created nature, thus not seeing real death but death by the fall of man's nature. This was common among those teaching original sin. In Adam real death of the body and soul were to occur , but many apologists spiritualized death as less than it was.

Nicodemus spoke of entering again into his mother's womb, and being born; but, if he could do so, to what purpose? If he were born of his mother a hundred times, that would not mend the matter, for still that which is born of the flesh if flesh; a clean thing cannot be brought out of an unclean. He must seek for another original, must be born of the Spirit, or he cannot become spiritual. The case is, in short, this: though man is made to consist of body and soul, yet his spiritual part had then so much the dominion over his corporeal part that he was denominated a living soul (Gen_2:7), but by indulging the appetite of the flesh, in eating forbidden fruit, he prostituted the just dominion of the soul to the tyranny of sensual lust, and became no longer a living soul, but flesh: Dust thou art. The living soul became dead and inactive; thus in the day he sinned he surely died, and so he became earthly. In this degenerate state, he begat a son in his own likeness; he transmitted the human nature, which had been entirely deposited in his hands, thus corrupted and depraved; and in the same plight it is still propagated.

Henry missed the point, man was fashioned from dust before Adam's sin. He didn't become earthly but was made earthly. Thus Henry's explanation wasn't accurate. Man was as much dust before Adam's fall. This doctrine is one reason the churches of Christ of Britain split in Henry's day. Many followed Henry into original sin but others stayed faithful. 54 congregations split and 7 became what later became baptists. 

Gen 2:7 And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.

Man was earthly before man's first sin, so man's nature never fell, it was always earthly. This is clear from I Corinthians 15.

"But God giveth it a body as it pleaseth him"

"It is sown a natural body, it is raised a spiritual body"

So God made us a natural body with the ability to sin, there was no fallen nature as people embracing original sin teach. They don't like this idea because God would originate sin, but making man with the ability to disobey or to do wrong isn't the same as God forcing sin, it is man's choice.

Tertullian seemed to have a good argument in refuting Marcion. Marcion believed in a dual God, The God of the Old Testament being evil and the God (Christ revealed)  of the New Testament being good. The argument Tertullian used against Marcion is also useful against original sin.

Adam was the diffuser of the knowledge of God to the whole creation, it is by this knowledge man becomes guilty before and without the law.

Tertullian argued

For indeed, as the Creator of all things, He was from the beginning discovered equally with them, they having been themselves manifested that He might become known as God. For although Moses, some long while afterwards, seems to have been the first to introduce the knowledge of the God of the universe in the temple of his writings, yet the birthday of that knowledge must not on that account be reckoned from the Pentateuch. For the volume of Moses does not at all initiate the knowledge of the Creator, but from the first gives out that it is to be traced from Paradise and Adam, not from Egypt and Moses. The greater part, therefore, of the human race, although they knew not even the name of Moses, much less his writings, yet knew the God of Moses; and even when idolatry overshadowed the world with its extreme prevalence, men still spoke of Him separately by His own name as God, and the God of gods, and said, If God grant, and, As God pleases, and, I commend you to God. Reflect, then, whether they knew Him, of whom they testify that He can do all things. To none of the writings of Moses do they owe this. The soul was before prophecy. From the beginning the knowledge of God is the dowry of the soul, one and the same among the Egyptians, and the Syrians, and the tribes of Pontus.

"In Adam" could be the idea of the knowledge he diffused about God to his offspring, so that all mankind would be without excuse. Through Adam came the consciousness of right and wrong.

The witness of Adam along with the physical creation was enough to make man accountable for serving or not serving the creator. All of creation is infused with this knowledge. Through Adam all knew God.

Rom 1:21 Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.

As you see their hearts were darkened after they had knowledge of God. So after infancy. Therefore original sin falls apart.