The Uniqueness of Personhood

One of the quintessential undertakings of philosophy is to define the essence of personhood. What, exactly, is it that makes me me? In a conversation over the past week, the idea was posed that I may be nothing more than my genetic makeup coupled with my lifetime of experiences - essentially, there is nothing more to man than nature and nurture. A place deep-seated within me, rebelled at the idea that there is no essence, no soul, no intentional uniqueness about me. I abhor the thought that were my genetic composition to be coupled with a precise replication of the entirety of my life's experience the result would be a direct clone of me in every aspect. The logic is sound by empirical standards, and yet I am compelled to insist upon a reality that is empirically imperceptible. I mean only that there exits an element of life that cannot be detected by present methods yet surely is real in the deepest sense of the word. I am troubled that my confidence is outside the bounds of rationalism - my epistemology is, consequently, inconsistent.