Sometimes this process of filling in gaps in the past becomes more complete.  Thus, for example, in recalling a particular night a week or so ago, I instinctively represent it to myself as so many hours of lying in bed with the waking sensations appropriate to the circumstances, as those of bodily warmth and rest, and of the surrounding silence and darkness.

It is apparent that I cannot conceive myself apart from some mode of conscious experience.  In thinking of myself in any part of the past or future in which there is actually no consciousness, or of which the conscious content is quite unknown to me, I necessarily imagine myself as consciously experiencing something.  If I picture myself under any definitely conceived circumstances, I irresistibly import into my mental image the feelings appropriate to these surroundings.  In this way, people tend to imagine themselves after death as lying in the grave, feeling its darkness and its chilliness.  If the circumstances of the time are not distinctly represented, the conception of the conscious experience which constitutes that piece of the ego is necessarily vague, and seems generally to resolve itself into a representation of ourselves as dimly self-conscious.  What this consciousness of self consists of is a point that will be taken up presently.

Illusions with respect to Personal Identity.

It would seem to follow from these errors in imaginatively filling up our past life, that our consciousness of personal identity is by no means the simple and exact process which it is commonly supposed to be.  I have already remarked that the very fact of there being so large a region of the irrevocable in our past experience proves our consciousness of personal continuity to be largely a matter of inference, or of imaginative conjecture, and not simply of immediate recollection.  Indeed, it may be said that our power of ignoring whole regions of the past and of leaping complacently over huge gaps in our memory and linking on conscious experience with conscious experience, involves an illusory sense of continuity, and so far of personal identity.  Thus, our ordinary image of our past life, if only by omitting the very large fraction passed in sleep, in at least an approximately unconscious state, clearly contains an ingredient of illusion.[132]

It is to be added that the numerous falsifications of our past history, which our retrospective imagination is capable of perpetrating, make our representation of ourselves at different moments and in different stages of our past history to a considerable extent illusory.  Thus, though to mistake a past dream-experience for a waking one may not be to lose or confuse the sense of identity, since our dreams are, after all, a part of our experience, yet to imagine that we have ourselves seen what we have only heard from another or read is clearly to confuse the boundaries of our identity.  And with respect to longer sections