As for what makes up ones “self” I have no answers. Even allowing for the existence of a soul tho, you cannot define it as a fixed eternal thing. So much of my belief system, including religion, has changed over the years for me to accept that self is any less fluid and evolving than cellular make up. You add to your “self” as you progress thru life, and to some extent you subtract that which doesn’t fit any longer.

For example while you still may be my young friend from the beermuda triangle you are also a husband, father, and scholar. While I rather suspect that you, like myself, do a whole lot less wandering around country roads drinking the cheapest beer imaginable.