52. The reason marriages in heaven do not result in the begetting of children, but that instead they experience a spiritual procreation, which is one of love and wisdom - the reason is that in the case of people who are in the spiritual world, a third element is missing, which is the natural element. This element is the containing vessel of spiritual things, and spiritual things without their containing vessel do not assume fixed form like those that are produced in the natural world. Also, regarded in themselves, spiritual things relate to love and wisdom. Consequently, it is spiritual things that are born of their marriages. We say that these are born, because conjugial love perfects an angel, since it unites him with his partner so that he becomes more and more human. For, as we said above, married couples in heaven are not two but one angel. Therefore by the conjugial union they fulfill themselves in respect to their humanity, which is to want to be wise and to love what has to do with wisdom.