disturbed assurance of personal identity.
Nay, more, even when such a recognition might seem to be difficult, if
not impossible, as in linking together the very unlike selves, viewed
both on their objective and subjective sides, of childhood, youth, and
mature life, the mind manages, as we have seen, to feign to itself a
sufficient amount of such similarity.

But this process of linking stage to stage, of discerning the common or
the recurring amid the changing and the evanescent, has its limits.
Every great and sudden change in our experience tends, momentarily at
least, to hinder the smooth reflux of imagination. It makes too sharp a
break in our conscious life, so that imagination is incapable of
spanning the gap and realizing the then and the now as parts of a
connected continuous tissue.[133]

These changes may be either objective or subjective. Any sudden
alteration of our bodily appearance sensibly impedes the movement of
imagination. A patient after a fever, when he first looks in the glass,
exclaims, "I don't know myself." More commonly the bodily changes which
affect the consciousness of an enduring self are such as involve
considerable alterations of coenaesthesis, or the mass of stable
organic sensation. Thus, the loss of a limb, by cutting off a portion of
the old sensations through which the organism may be said to be
immediately felt, and by introducing new and unfamiliar feelings, will
distinctly give a shock to our consciousness of self.

Purely subjective changes, too, or, to speak correctly, such as are
known subjectively only, will suffice to disturb the sense of personal
unity. Any great moral shock, involving something like a revolution in
our recurring emotional experience, seems at the moment to rupture the
bond of identity. And even some time after, as I have already remarked,
such cataclysms in our mental geology lead to the imaginative thrusting
of the old personality away from the new one under the form of a "dead
self."[134]

We see, then, that the failure of our ordinary assurance of personal
identity is due to the recognition of difference without similarity. It
arises from an act of memory--for the mind must still be able to recall
the past, dimly at least--but from a memory which misses its habitual
support in a recognized element of constancy. If there is no memory,
that is to say, if the past is a complete blank, the mind simply feels a
rupture of identity without any transformatio