16. All this may be illustrated by comparison with a tree. The prime source of a tree is a seed, and in this there is an endeavor to bring forth fruit. This endeavor, roused to activity by heat, brings forth first a root, and then from that a stem or stalk with branches and leaves, and at last the fruit; and in this way the endeavor to bear fruit comes forth into manifest being. From this it is evident that the endeavor to bring forth fruit is constant through the whole progression until it attains manifest being, for if it ceased the capacity to vegetate would die at once. This is the application: The tree is man; in him the endeavor to bring forth the means is from his will in his understanding; the stem or stalk with branches and leaves, in him are the instrumental means, and are called the truths of faith; the fruits which in the tree are the ultimate effects of the endeavor to bear fruit, in man are uses and in these his will comes forth into manifest being. From this it may be seen that the will to bring forth uses by means of the understanding is constant through the whole progression, until it comes into manifest being. (Concerning the will and the understanding, and their conjunction, see the Doctrine of Life for the New Jerusalem, n. 43.)