1. According to the account of original sin in Genesis, a minimal human community, a man and a woman, was involved. Although the woman’s sin was first, it was not decisive. The man’s was, so that the common responsibility was primarily, although not exclusively, his.
2. For the sake of argument, the theory of polygenism, according to which the minimal human community must have been a sizable group, is granted here. It is also assumed that this was one interbreeding population with a potentiality for communication and social cohesion. Note, finally, that any social group can act as a group (see 2‑E).
The Church’s teaching about this initial human condition has been stated above. What does theological speculation appropriately add to this picture?
First, it seems appropriate from a theological point of view to add that Man not only emerged from the hand of God but also organically emerged from subpersonal antecedents. A subpersonal creation which is like God not only in existing but also in causing other things to exist is a more perfect manifestation of God’s goodness than a subpersonal creation which simply exists as a setting for these other things. In particular, a subpersonal creation which has a share in causing the very image of God to come to be in the world is more noble than one which has no such share. Just as Mary and the whole of Israel are ennobled by the role which they play in the Incarnation of the Word, so the natural world (including our primate antecedents) is ennobled by doing its part, albeit nonconsciously, in the coming to be of persons within nature (see S.c.g., 3, 69).
Second, it is appropriate to assume that the condition of primal humans was no more different from our condition than must be assumed. The basis is Ockham’s razor. On this assumption, we ought to suppose that the primal Man’s awareness of God was much like our own: faith in revelation. He had ground enough to believe in God and his promises, but no knowledge of what immortality and everlasting life might be like. He knew the difference between right and wrong, but saw no more clearly than we the implications for his friendship with God of doing what is wrong.
Third, while the biological evidence indicates that humankind emerged from a very large, widely scattered, interbreeding population, theology must assume that the spiritual capacity for free choice was given initially by a special divine intervention, which completed hominization, to a group of individuals small and cohesive enough to function socially as a single body. In this way, solidarity in sin by the whole of humankind was possible at the beginning. As additional groups were hominized, they emerged into an already-given existential situation, and so shared prior to any personal act in the moral condition of humankind. In this sense, they shared “by propagation not by imitation” (DS 1513/790), even if not all humans were lineal descendants of a single couple.
3. No matter how a group is organized, someone’s action is decisive. (In a group which operates by simple majority voting, for example, the vote which makes the majority is decisive.) Primate hordes are structured socially, with a single dominant leader; supposing the transformation of a primate group into a human extended family, it is reasonable to suppose that it would have a similar social structure. Thus, there is no obstacle to thinking the original human community had a single leader whose action was decisive for its action as such. We can call this individual “Man.”
4. As was explained in D above, the primitive condition of the first humans cannot be supposed to preclude free choice and sin. Once there were humans, they could make free choices and so could sin. It is a mistake to suppose initial goodness would have ruled out the possibility of temptation and, thus, of sin. Even emotional inclinations which are natural and in themselves good cannot always be followed reasonably, because they are not always consistent with integral human fulfillment.
5. It is evident that a large group of people can be carried away by a common wave of emotion and unreasonable thinking and so go wrong together. Moreover, factional conflict, in which questions of social control are settled by power with unfairness on all sides, is very common. Even in such factional contention there is common responsibility for accepting the use of unfair means; at the same time, the individual with primacy in the society has the primary responsibility for any general resort to violent means of settling issues.
All sorts of possible temptation situations which will meet the requirements of the original condition can be imagined. For example, leaders of groups and their followers often have disagreements in judgment about what is best for the group. Perhaps such a disagreement arose—for instance, about whether the time was ripe for Man to turn over leadership (changes in leadership do occur in all groups). Not out of any unruly passion or selfish inclination established by previous sin, for these are excluded by hypothesis, but out of a judgment that the problem threatened the whole group’s well-being, Man may well have decided to cripple his brother.
The wrongness of such an act would have been obvious to Man. But all the consequences of doing wrong need not have been clear. Moreover, human freedom in this case would first have encountered its own paradoxical character. If the wrong is done, human good—the well-being of the group—seems to be promoted. The choice to do wrong does have a negative aspect with respect to human good, but so does the choice not to do wrong! True, God had warned against doing it. But the warning was not an evident truth. Perhaps—in this “perhaps” is a role for Satan—the submission to moral limits is something God demands for his own good, not for ours? In that case, one can assert one’s human dignity by rejecting God’s warning to do only what is morally right (see S.t., 2–2, q. 163, a. 2).
6. Every morally evil act is a sin, even though there is no direct choice of something else in preference to God (see 13‑D). To act against reason is to alienate oneself from God in whose wisdom and goodness human reason and fulfillment are participations. Moreover, as faith teaches, some sort of revelation and covenantlike relationship existed at the beginning between God and humankind. Thus it is reasonable to assume that Man was aware that moral evil would disrupt friendship with God.
7. It is not necessary to suppose that humankind in general and Man in particular fully comprehended the significance of the sin they were tempted to commit. Indeed, Genesis suggests that, inasmuch as the comprehension of evil comes from experiencing its consequences, it was only by experience that Man learned the whole human meaning of evil. Thus, those who first sinned could have known right from wrong without fully appreciating in advance the significance of their wrongdoing.
8. Nor, to have involved us all in his sin, need Man have thought of himself as acting on behalf of humankind at large (see I below). Our existential involvement follows from our natural solidarity with humankind at the beginning, for whose social act the sin of Man, the leader of the first human social group, was decisive. One in species, humankind could and should have been one community in friendship with God, but by sin from the beginning instead constituted the broken human world.