Part of the extended series Evidence for the Faith
Are you the same person you were when you were two years old? Not entirely: you’ve changed in many ways since then. But are you the same person? I heard someone recently ask it this way: were you ever two years old? Of course you were. Whatever the differences between the you of today and the two-year-old you, there is something about you that has endured across the years, to make you the same “you” now that you were then, in spite of all that has changed in the meantime.
What is that something? What is it about you that has caused you to remain you? What is personal identity, and how does it endure?
There is a mystery here, not easily resolved by naturalistic explanations. It constitutes one thread in a line of cumulative evidences for Christian theism. It is far from the strongest thread—I would not bank my entire belief-set on it, and I’ve only dabbled in study on this—but it is a fascinating one.
The ancient Greeks wondered about a ship whose parts were replaced one by one over the years until none of the original remained. At the end, was it the same ship? I prefer the farmer’s story: “I’ve had this axe my whole life. I’ve had to replace the handle a few times, and it’s needed a new axe-head every dozen years or so, but it’s been a good axe, and I wouldn’t trade it for any other.”
Are you the same “axe” you were as a baby? Most of your body is far younger than you are. Your brain cells may be the same age as you, but almost nothing else is. Or perhaps even your brain cells are younger than you are. Were you ever a fetus? If so, then you were you at the time, even without all those neurons in place. (Some of you reading may doubt that you were really “you” when you were a fetus. That is to say, you doubt that whatever-there-was-that-was-about-to-become-you was really you when whatever-was-about-to-become-you was a fetus. That’s not just clumsy English—though it is indeed that. It’s nonsensical on its face.)
Physically, you are not what you once were, yet you are still who you once were. How is that possible?
Perhaps you are the same you now as before, just because you can trace a line of physical continuity, or continuity of memories, from then until now. Physical continuity seems a weak explanation for continuing identity, however, for reasons already mentioned. Continuity of memory seems more promising; but what about the person with amnesia? When his wife finally finds him and says, “Thank goodness, you’re alive!” is she wrong to identify him as her husband? If he asks, “Who am I?” and she answers, “You’re my husband,” is she wrong? If continuity of memory is the explanation for continuity of identity, then the “you” who was her husband no longer exists; the man is a different “you” in every sense that matters. But this is nonsense. He may not realize he is that person, he may not perceive it, but undoubtedly he is.
When my sister was in a coma for three weeks, we spoke words to her like, “We love you. We’re praying for you.” Were we wrong to think that was really her? Certainly not–even though for that period there was no continuity of experience or memory to her.
But the problem is even greater than that. If I say I am the same “I” that I was at two years old—or even two years ago—because I have experienced some continuity of memory since then, all I’m saying is that there exists in my mind today a memory that I ascribe to myself through that duration. But if I say this, I’m assuming it was “I” who had those experiences, who formed and retained those memories. I’m saying that they have been “my” memories throughout this period of continuity. This is illegitimate bootstrapping. If my continuing identity really does depend on me having developed and holding those memories, but my developing and holding those memories depends on my having had a continuing identity, then we have the existence of A depending on the existence of B while the existence of B depends on the existence of A.
The Parts and the Self
There is also the puzzle of the parts and the whole. My foot hurts; that means I hurt. My stomach has been empty for a while; that means I am hungry. The foot is not the stomach, but there is a sense in which I can say “I” when I speak about both of them. The parts have an identity relationship of sorts with the self, without being identical with the self.
That may seem fairly innocuous, but not so much so when we consider the brain instead of the foot or the stomach. When patients are diagnosed with dementia they experience a paradoxical sense of relief: “It’s not me, it’s only my brain.” As I point out in that linked article, I doubt this is just a false conclusion flowing from dementia. I think it’s a valid conclusion from the premise, I am intimately related to my body, yet I am not my body.
An Argument Against Atheism
I write these thoughts based on admittedly too little research. This is not (I repeat) my strongest argument for Christian theism.
Still I think there is something more to it than a mere mental puzzle. I am convinced I was once a younger man, and that the person I am now is, in essence, the same person I was then, even though in many properties and characteristics I am different. It seems to me that only one thing makes this possible, and it’s wrapped up in that important word “essence.” There is something that is essentially me, inherently me, enduringly me, despite all that has changed about me over the decades of my life.
I cannot imagine anything in philosophical naturalism—the view that reality is nothing but matter and energy interacting in space and time according to necessity and (perhaps) chance—that would supply that inherent, enduring, essential me-ness. So while this is not the greatest argument for Christian theism, I think it has force against naturalistic atheism.
Personal Identity: The Question
Am I wrong? In my admittedly brief readings on this topic, have I missed some satisfactory naturalistic explanation for human identity? Or is this a real problem for naturalism, as I think it is? I’m open for your input.
(P.S. for those who are wondering: yes, I am finally picking up this series again.)