"I think, therefore I am... I think."
Nordom, Planescape: Torment
When I was younger I was terrified by the thought that every night when I went to bed, I was killed in my sleep and replaced by a clone with identical memories. To go to sleep was to create a pause, a space, an interruption in the continuity of my consciousness: How could I know it was still me that took up where the previous me left off? I would wake in the morning, and lie in bed as I went over my memories, pondering: are these mine? Am I still me?
"All is flux; nothing stands still."
Heraclitus
Heraclitus said that no man can ever step in the same river twice, because he is never again the same man, and it is never again the same river. The passage of time is the passage of change. Even as I write and even as you read, change is happening. Our cells shrivel up and die and are replaced - the body that you had when you were born has by now been entirely replaced by food. The neural network that is our brain processes information and is forever altered by the information: neural paths are closed and new ones are created. We live second to second as if in an animation. The transitions seem to flow smoothly and naturally, but slow it down, freeze it frame by frame and you will see the minute differences; the tiny alterations of you. You are not the same person from one frame to the next.
Change is not an illusion, as Parmenides and Zeno argued - rather, it is the state of being which is the illusion. Permanence is a human lie - everything in this world is transient, temporary. Including the notion of you.
So it would seem my younger self's fears weren't entirely unfounded. When I wake up in the morning, I'm not the same person as who I was when I went to sleep the previous night. I have changed. Zahir A has vanished, and Zahir B has stepped in to take his place. If anything, my younger self was being entirely too naive. The change is happening not just when I sleep, but at all times, during my sleeping as well as my waking hours, all without me realizing it. An iteration of me is lost and replaced with each moment to the next. I die a million deaths every day.
"I yam what I yam and tha's all what I yam!"
Popeye the Sailor Man
Who is the "I" that lurks in the darkness behind our eyes? It has been documented that people who suffer massive brain damage can likewise experience massive changes in personality - the self and the physical form are not so easily separated as one would like to think. And yet if you were to take a human brain and disassemble it, piece by piece, you would not find a soul. You would not find an "I". All you would have left is a dissected brain. In searching for it, you have destroyed it. So what is it then? Some intangible value? Something beyond the senses?
Yet we do sense it - don't we? You feel like you. You feel that there is a "you". Don't you? What does it mean to say, "I don't feel like myself today"? Is it simply that our behavior has diverged from some established mean? But human behavior itself is hardly consistent - we act differently in different environments. We can be animated and talkative among close friends, yet quiet and withdrawn among strangers. We can be kind and compassionate to our mothers, yet cold and distant to an acquaintance. If even daily behavior is so fluid, how can we lay claim to a concrete identity?
Perhaps it is so difficult to define identity because identity itself is something that is vague and indistinct - a haphazard collective of a person's thoughts and feelings and memories and beliefs? All of which are constantly changing. In one instance to the next, new memories are gained and older memories are lost or overwritten (are you absolutely certain you correctly remember everything that has happened to you? Barring an eidetic memory, I think not). Our beliefs and perceptions of the world are constantly challenged and changed by new experiences. If identity is memory and perception, then we change identities each time we learn something new or forget something we once knew or change our views about something that we once held as unshakeable truths. There is a reason why a change in one's opinion is called "changing one's mind".
Who, then, is this person who is sitting at his keyboard typing this right now? What is this thing that is thinking these thoughts right now? A person with a soul? An automaton that thinks it is thinking? The nth iteration of something that exists only within the frame of a second, erased by time and replaced by another iteration the very next moment? Is there really a me, or am I simply some random assortment of living cells, bound together in symbiosis and fooling itself into thinking it is a single entity?
Does identity have a meaning, or are we all simply figments of our own imaginations?