A Puzzle: Self Continuity

There are only a few exotic questions that have puzzled me since my being acquainted with them. I'm sure I'll come to explore them all in this blog. The one I'll explore here is the problem of self continuity. I came up with the question myself but later found it to be a topic already discussed among scholars from a range of different studies.

Beginning with definitions, we'll bar defining the self as an immaterial, everlasting entity that transcends death or this "mortal coil." Lets instead presume that the self is constituted by the brain and its neural and chemical structures, all memories, precepts, concepts and sensations exist therein. These aspects of a person's mental landscape can be described in terms of a specific arrangement of energy and matter, and therefore so can an "I" be described in those terms. This is as relevant to the body as it is to the consciousness.

This poses a problem, however, to our usual way of thinking about ourselves. Between no two instances is there a continuously sustained arrangement of energy and matter. Take, for example, "myself" as an infant. What arrangement is shared between myself at present and myself twenty-one years ago? Not a single structure in my physiology has remained unchanged between then and now, so what is the basis for continuity between us? It is not in my genome, for if I'd had a twin, my twin would share the same genome but would not be myself. Likewise, any somatic cell taken from my body has a complete copy of my genome but is not said to be "me." It is merely a part of me. So what constitutes the whole, and what constitutes the continuity of the whole between any two instances?

Are those that look at a picture of their younger selves and say "that's me" mistaken?

The puzzles persists on much smaller timescales as well. We needn't look to ourselves in years prior to see the discontinuity; at no two fractions of a second do I retain the same material composition. The composition of each of my cells, each of their constituent parts, and each neurochemical thought process is in constant flux. This means that if the "I" is a specific arrangement of matter and energy, then at each indivisible instant of time, I die and someone else takes my place. Arguably, such divisions of time are arbitrary, and there is only one continuous flow. At that scale, the "I" no longer exists and experience becomes "disembodied" from it. This is how Buddhists regard things, that experience exists without an experiencer, and it is a troubling proposition to my precious egoism.

How could I value myself above all else and act upon that reverence if "I" exist too briefly to even formulate a thought or if "I" exist in no definite terms at all? Should I exist under some kind of collectivistic individualism, by which I value all of the countless persons that comprise me from one second to the next? Why would I do that? What makes the distinction between any two of them different from the distinction between any two random people, myself and a stranger for instance?

I do not know how to resolve this problem to my satisfaction. A different definition of the self may suffice. Perhaps if I were to define the self as a general pattern (compare to a specific arrangement) that changes along a gradient. Perhaps any overlap between two arrangements on the gradient would constitute continuity between two instances, but does such overlap even occur on very small time scales? I will have to think on this for some time.