Loneliness seems to be an essentially human experience. It is not just about being alone. Loneliness is not the same thing as solitude. We can be alone yet happy, because we know that we are part of a family, a community, even the universe itself. Loneliness is a feeling of not being part of anything, of being cut off. It is a feeling of being unworthy, of not being able to cope in the face of a universe that seem to work against us. Loneliness is a feeling of being guilty. Of what? Of existing? Of being judged? By whom? We do not know. Loneliness is a taste of death.

- Jean Vanier, Becoming Human, p. 33