Who am I? Who are you? What makes us the individuals that we claim to be? Who and/or what is it that perdures through time that gives us this continuity we call "the self"?
A big part, if not the exclusive part, in Schild's Ladder of who we are is that of memories. There are the constant references to the loss of some short-term memories experienced when local death occurs to the individual and they have not backed up their recent experiences, some times just a couple of hours sometimes close to a day or so. But I think that memories may be given to much emphasis in this quest for identity.
It seems to me that there must be a "something else" that which the memories accrue to, that which maintains them, and that which perdures throughout. If who we are or who we become is the sum of our memories then every moment I am a different person. While it may be the case that I am a changing person for at each moment I gain a new experience and thus a new memory and perhaps forget some trivial memory, I do change. But there is an "I" that remains constant an "I" that binds together past, present and future. this "I" is not only and necessarily memories. It seems it must be something more.
Take the case of amnesia, permanent or other wise, I still am though I have lost all memories. Perhaps I no longer remember that I am was a welder, but I am. Perhaps I no longer remember that I used to be able to play chess but I am. Memories are perhaps a important part of how we define our self in a functional way, but I argue that they are not sufficient for defining who we are in an essential way. Before I learned to weld I was, before I learned to play chess I was and after I forget how to weld or play chess I will still be.
Perhaps the I that perdures is some ineffable thing, perhaps it is the ultimate subject that can never become object to itself. But what ever else it may be its essential nature is not tied to memories.
In Schild's Ladder Mr. Egan either ignores this or does not wish to deal with it, or perhaps also he is a pure materialist so who we are is nothing but the brain. But then that too would not make us our memories it would make us our brain whatever its state is.
Simply put I argue that we are more than the sum or lack of our memories. Memories add to us and there loss perhaps dimishes us but memories neither create nor destroy who we are, that "I" remains and is the constant to which memories come and go.