Consciousness is thus constantly surrounded by a retinue of phantom objects. These objects, although at first sight possessing a sensible aspect, are not the same as those of perception…Soon as we try to observe one of them we find ourselves confronted with strange creatures beyond the laws of the world of realities. They always occur as indivisible wholes, as absolutes. At once ambiguous, impoverished and dry, appearing and disappearing in a disjointed manner, they invariably occur as a perpetual “elsewhere,” as a perpetual evasion. But the evasion to which they invite is not only of the sort which is an escape from actuality, from our preoccupations, our boredoms, they offer us an escape from all worldly constraints, they seem to present themselves as a negation of the condition of being in the world as an anti-world.

Jean-Paul Sartre, The Psychology of Imagination