Neither individuality nor substance can provide a sufficient account for the uniqueness of human persons. This problem is demonstrated with respect to the various ways one can describe the human person; matter, substantial form, essence, and nature. It is nature that describes beings as they exist. Because human nature is distinctively rational, human beings are most appropriately described as persons. An investigation of personality reveals that each person stands in a unique relation to being by virtue of the acts of intellect and will. Therefore, only personality provides a sufficient account of the uniqueness of individual persons. But because personal uniqueness is an aspect of relation, it cannot be conceived outside that relation. And as the person’s relation to being is tantamount to his ability to enter into communion, uniqueness necessarily implies communion.