Diversity involves difference, but not all difference is diversity. Diversity requires a background of sameness, of a shared nature and shared values. Diversity is difference that still speaks to us, presenting possibilities we might pursue and challenges to which we might rise. Diversity is difference in which we see ourselves, in both our possibilities and our failures.

As biological specimens, humans vary in innumerable ways, small and large, but not all biological difference is the kind of diversity we celebrate. Diversity involves the differences that matter, that reveal our essences and that challenge our self concepts. We are revealed to ourselves by what we recognize as diversity and how we respond to it. Differences can matter to us in two different ways, in ways that celebrate who we are and in ways the challenge it.

We notice some differences because they demonstrate the full potentialities of a form and nature that we share, because they reveal more perfectly what we might be and the beauty of a form in which we participate, that is us. There are countless kinds of laughter, of smiles, of dancing, music, cuisine, and culture. There is a dazzling panoply of different kinds of well-formed human bodies, faces, movements, and expressions. Plato had seen long ago that a fundamental feature of form is its expansiveness, its ability to expand outward into more and more different reflections of itself. In the Timaeus, he remarks of the creator that it would have been regarded jealous, or miserly, had it held back any measure of its overflowing goodness, any possible reflection of its form. Normally we make choices and pursue one possibility, disciplining ourselves to the perfection of one possible flowering of form. But it is the essence of joy and of celebration to overflow boundaries, to seek more and more expressions of ourselves. Differences are beautiful because they are us, our human form, our nature, unconstrained by the boundaries that limit one individual and allowed to flower freely. They celebrate a fullness of human life that no one of us can hold.

Difference can also challenge us. But how it challenges us also reveals who we are, our most fundamental faults, and our most essential value. As far as I can see, differences challenge us in three related ways: (a) they challenge the integrity of the communities in which we develop most fully; (b) they reveal to us our vulnerabilities and fears; and (c) they reveal to us our moral failings. Diversity flowers from the similarity behind our differences and, in so doing, reveals our failures to remain true to our common source.

All of the various forms of our individuality require nurturing and care within a community or family. The purpose of a family or a community, of civilization itself, is to allow for the safety, security, and intimacy in which our individuality can grow and perfect itself most freely. There is in us, therefore, a deeply ingrained, perhaps even biological, tendency to resist the stranger, the different, whatever threatens our communities. There is a fundamental tension involved here: On the one hand we see the necessity of communities that nurture our individuality: we all know what it is like to belong, to be brought inside, to come home. On the other hand, it is the very preciousness of this sanctuary that leads us to exclude those who are different enough to make us feel them a challenge to its integrity. Every community that aims to be diverse must struggle with this tension: We build a community on shared values to foster the growth of the forms of individuality we have chosen, but this makes us exclude those who do not share those values. It is a mark of our status as creatures that we can express the diversity of human nature only in particular ways, as the individuals we choose to be, and that these choices exclude others.

But all this begs the question: Why do we feel difference to be a threat? What differences matter enough to place someone on the outside? What differences define our community? Who is our neighbor? The strong need not fear, and what we know with certainty can admit no doubt. This means that the differences that threaten us reveal our weak spots. Just as we only revel in the diversity that reflects back on our common nature, so we only fear the differences that still present real possibilities for us, that still have some secret hold on us, the reveal some weakness. If someone likes broccoli, while we are allergic to it, we do not feel threatened by their difference. When a difference really gets under our skin, it is always because, in some sense, it really is already within our skin. We feel the pull of that alternative in our common humanity; the spark that lights its fire feeds our flame too. But we feel it pulling us away from the space we have created for our own individuality.

Of course, this reveals the answer to the question “Who is our neighbor?” and the most fundamental way in which difference challenges us. Beneath every difference, in the face that looks out at us, we feel the common spark, the common nature that makes them feel different to us. They are us. Their individuality tries to express the same life as ours. They deserve what we deserve. And yet we feel their difference. They are on the outside, and we fear to let them in. They are our neighbors, yet we cannot bring ourselves to treat them as ourselves. One of Dostoevsky’s major insights was that we do not hate people because of what they are or what they did, but because of what we did to them or what they make us see about ourselves. Seeing difference indicts us of our inability to rise above it. It reminds us of what we would rather not see: that all men are our neighbors and that we cannot bring ourselves to love them as ourselves. Much of the hatred we feel for those different than us involves this deflection of guilt and a demonizing of their differences to escape it.

Now, diversity is not the absence of discrimination. The purpose of education is to make certain kinds of discriminations, between the true and the false, the good and the bad, the beautiful and the ugly. Valuing diversity does not mean that anything goes and that all alternatives are equal. We don’t value a diversity of answers to the question “What does 2 times 3 equal?” Debating our differences about how we make these discriminations is no threat to the real basis of our community. But some human differences are expressions of what we have in common, and the value of our humanity lies in the common spark from which our individuality flows. We may not make the same discriminations another person does, but if we find our differences worth talking about we recognize them as flowing from values we share. We may not love the actions and opinions of every person in their diverse forms, but we are called to love spark of humanity, in all its conflicts and convolutions, that gives rise to them. They are us; they are our neighbor, and the hospitality of a community that brings them inside can only make it stronger.

There are many kinds of diversity: diversity of styles and preferences, diversity of cultures, diversity of religious belief, diversity of gender and sexual preference, diversity of races and nationalities, diversities too diverse for enumeration; yet all of them reflect our similarities as much as our differences. Diversity celebrates the flowering of the full potential of being human and challenges us to ask of those who, in their flowering, are different from us: Where can I belong, if they do not belong? What do I fear in myself if I fear them? How can I value myself, if I do not value them?