XVIII. (59) But the tree of life is that most general virtue which some people call goodness; from which the particular virtues are derived, and of which they are composed. And it is on this account that it is placed in the centre of the Paradise; having the most comprehensive place of all, in order that, like a king, it may be guarded by the trees on each side of it. But some say that it is the heart that is meant by the tree of life; since that is the cause of life, and since that has its position in the middle of the body, as being, according to them, the dominant part of the body. But these men ought to be made aware that they are expounding a doctrine which has more reference to medical than to natural science. But we, as has been said before, affirm that by the tree of life is meant the most general virtue. (60) And of this tree Moses expressly says, that it is placed in the middle of the paradise; but as to the other tree, that namely of the knowledge of good and evil, he has not specified whether it is within or outside of the Paradise; but after he has used the following expression, “and the tree of the knowledge of good and evil,” he says no more, not mentioning where it is placed, in order that any one who is uninitiated in the principles of natural philosophy, may not be made to marvel at his knowledge. (61) What then must we say? That this tree is both in the Paradise and also out of it. As to its essence, indeed, in it; but as to its power, out of it. How so? The dominant portion of us is capable of receiving everything, and resembles wax, which is capable of receiving every impression, whether good or bad. In reference to which fact, that supplanter Jacob makes a confession where he says, “all these things were made for Me.”{12}{#ge 42:36.} For the unspeakable formations and impression of all the things in the universe, are all borne forward into, and comprehended by the soul, which is only one. When, therefore that receives the impression of perfect virtue, it has become the tree of life; but when it has received the impression of vice, it has then become the tree of the knowledge of good and evil, and vice and all evil have been banished from the divine company. Therefore the dominant power which has received it is in the Paradise according to its essence; for there is in it that characteristic of virtue, which is akin to the Paradise. But again, according to its power it is not in it, because the form of virtue is inconsistent with the divine operations; (62) and what I here say, any one may understand in this manner. At this moment, the dominant part is in my body, according to its essence, but according to its power it is in Italy, or Sicily, when it applies its consideration to those countries, and in heaven when it is contemplating the heaven. On which principle it often happens that some persons who are in profane places, according to their essence, are in the most sacred places, thinking of those things which relate to virtue. And again, others who are in the temples of the gods, and profane in their minds, from the fact of their minds receiving a change for the worse, and evil impressions; so that vice is neither in the Paradise, nor not in it. For it is possible that it may be in it according to its essence, but it is not possible that it should be according to its power.