It is only when we can be sufficiently intimate with ourselves that we can be comfortable both alone and with others.
Whereas the common definition of “solitude” is the state of being alone, solitude (in contrast to loneliness) paradoxically implies the subjective presence of the other. From this perspective, loneliness can be thought of as a failed experience of solitude.
From INQUIRING DEEPLY, Reflections on Connection (ch.6)