<P> In the City of God (xiii. 20 - 21), Augustine of Hippo offers great allowance for "spiritual" interpretations of the events in the garden, so long as such allegories do not rob the narrative of its historical reality . Enlightenment theologians (culminating perhaps in Brunner and Niebuhr in the twentieth century) sought for figurative interpretations because they had already dismissed the historical possibility of the story . </P> <P> Others sought very pragmatic understandings of the tree . In the Summa Theologica (Q97), Thomas Aquinas argued that the tree served to maintain Adam's biological processes for an extended earthly animal life . It did not provide immortality as such, for the tree, being finite, could not grant infinite life . Hence after a period of time, the man and woman would need to eat again from the tree or else be "transported to the spiritual life ." The common fruit trees of the garden were given to offset the effects of "loss of moisture" (note the doctrine of the humors at work), while the tree of life was intended to offset the inefficiencies of the body . Following Augustine in the City of God (xiv. 26), "man was furnished with food against hunger, with drink against thirst, and with the tree of life against the ravages of old age ." </P> <P> John Calvin (Commentary on Genesis 2: 8), following a different thread in Augustine (City of God, xiii. 20), understood the tree in sacramental language . Given that humanity cannot exist except within a covenantal relationship with God, and all covenants use symbols to give us "the attestation of his grace", he gives the tree, "not because it could confer on man that life with which he had been previously endued, but in order that it might be a symbol and memorial of the life which he had received from God ." God often uses symbols - He doesn't transfer his power into these outward signs, but "by them He stretches out His hand to us, because, without assistance, we cannot ascend to Him ." Thus he intends man, as often as he eats the fruit, to remember the source of his life, and acknowledge that he lives not by his own power, but by God's kindness . Calvin denies (contra Aquinas and without mentioning his name) that the tree served as a biological defense against physical aging . This is the standing interpretation in modern Reformed theology as well . </P>

What is the fruit in the tree of life