uncertainties about identity

 

The past is all of one texture—whether feigned or suffered

— whether acted out in three dimensions, or only witnessed

 in that small theatre of the brain which we keep

 brightly lighted all night long, after the jets are down,

 and darkness and sleep reign undisturbed 

in the remainder of the body. 

 There is no distinction on the face of our experiences;

 one is vivid indeed, and one dull, and one pleasant, 

and another agonising to remember;

 but which of them is what we call true, 

and which a dream, there is not one hair to prove. 

 

 The past stands on a precarious footing; 

another straw split in the field of metaphysic, and behold us robbed of it.

...

the past, ... is lost for ever: our old days and deeds, our old selves, too,
and the very world in which these scenes were acted, all brought down to the
 same faint residuum as a last night's dream, to some incontinuous images,
and an echo in the chambers of the brain.  Not an hour, not a mood, 
not a glance of the eye, can we revoke; it is all gone, past conjuring.  And 
yet conceive us robbed of it, conceive that little thread of memory that
we trail behind us broken at the pocket's edge; and in what naked nullity
should we be left! For we only guide ourselves, and only know ourselves,
by these air painted pictures of the past.

~  Robert Louis Stevenson

 from A Chapter on Dreams,
The Complete Works of Robert Louis Stevenson 
art by Arthur Boyd