Every person’s life is bound up with his membership in the community.  I am more than just a solitary atom; I am a part of a whole.  But the individual's identity is not exhausted by his membership in the community.  As Thomas Aquinas explains, the kind of unity that the commonwealth enjoys is not a "unity of essence" or a "unity of matter," but only a "unity of order," amounting to no more than the fact that things stand in a shared relationship.  "To be one in respect of order is not to be one unqualifiedly speaking," he says, "since unity of order is the least of unities."

Consequently, although I am a part of the community, I am not only a part.  A person is not like a hand, which takes its entire identity from the body to which it belongs.  He is a complete being, subsisting of himself, distinct from all else, the ultimate possessor of his properties in the sense that they are predicated of him, not of anything or anyone else.

Even so, his membership in the community matters.  It is not just something that affects him, but something about him.  The fact that I am a part does not imply that I am only a part; but neither does the fact that I am not only a part imply that I am not a part.