The sin of Adam is original sin, for two reasons. We all inhabited.. potentially, in Adam, namely in his procreative power, and in this way we participated in his free decision and thus are guilty. This again is of course myth, and a very questionable myth.
Secondly, he introduced libido, desire, concupiscence, into the process of sexual generation, and this element was given by heredity to all the others. Everybody is born out of the evil of sexual desire. Original sin in everybody is, as in Adam, first of all spiritual sin, sin of the soul. But it is also bodily sm, and Augustine had great difficulties in uniting the spiritual character of sin in everybody with the heritage- character which comes from Adam.
In this way everybody belongs to a “mass of perdition,” to a unity of negativity, and the most striking consequence of this is that even the little infants who die early are lost. Since everybody, by hereditary sin, belongs to the mass of perdition, nobody is saved who is not saved by a special act of God. This is the most powerful emphasis on the unity of’ mankind in the tragedy of sin. He denies, in this way, most radically and almost in the sense of his Manichaean past, the freedom in the individual personality. The embracing unity makes us what we are. Now if we look at our modern research into depth psychology and depth sociology, we probably are able to understand better than our fathers did what Augustine means, namely the inescapable participation in human existence, in a social structure and in an individual psychological structure, whether we call it neurotic or something else; it is something which we can see better today. The question which is put before us, of course, is:” What about the participation of the individual in guilt ?, and there is no answer to this in the context of Augustine.