An affinity for solitude is comparable only to one’s affinity for certain other people. And yet one’s first experience of solitude, like one’s first experience of the other, is fraught with danger… The absence of the visible and the absence of the object; and the risk, as in dreams, that innermost thoughts will come to light. For this reason, perhaps, it is the phobia relating to solitude that for some people persists throughout life.
It is the infant waiting too long for his mother that is traveling toward death because, unattended, he is in the solitary confinement of his body. Solitude is a journey, a potentially fatal journey, for an infant in the absence of sufficient maternal care. But it is worth remembering that the infant in the dark, the infant by himself, is not only waiting for the mother. Sleep, for example, is not exclusively a state of anticipation. It is, of course, difficult to conceive in psychoanalytic terms of an absence that is not, in some way, anticipatory.
Through desire the child discovers his solitude, and through solitude his desire. He depends upon a reliable but ultimately elusive object that can appease but never finally satisfy him.Adam Phillips (psihanalist) - On Risk and Solitude