The single most baffling feature of The Ancient Mariner, given the weight of suffering that follows, is that no cause is shown for the Mariner's shooting of the Albatross. The Argument of 1800 moralizes but does not give a motive: "how the Ancient Mariner cruelly and in contempt of the laws of hospitality killed a Sea-bird." All of the moral importance of the crime accrues in retrospect. Yet the Mariner himself, according to the arguments put forward above, is an unreliable narrator, and the other witnesses, the Mariner's shipmates, are equivocal over the meaning of the act. In itself the act seems relatively trivial in comparison with the dire consequences that ensue; it cannot, as an act, bear the moral weight that is put upon it.

In support of his Christian view of the poem, Robert Penn Warren saw the motiveless crime of the Mariner as symbolic of the Fall, and congruent with Coleridge's adherence to the doctrine of original Sin. The will of man is fundamentally corrupt, and in the Mariner's act we watch this corruption. "The lack of motivation, the perversity. . .is exactly the significant thing about the Mariner's act" (Warren). But this is to replace one mystery by another. The sense of guilt operative in the poem is too powerful to be dissolved in such a general metaphysical belief -- one which modern readers moreover cannot be counted on to share. The guilt is reflected elsewhere in Coleridge's writings, and clearly has a personal source (cf. D. W. Harding). Warren argues rightly that we must "distinguish the themes inherent in the poem as such from the personal theme or themes which remain irrevocably tied to the man" (Warren), but it may be possible to show that Coleridge's personal guilt touches us all. This would be not Original Sin, but a risk of the human condition.