I was in line, waiting to buy a coffee (caffeine is the one drug I can’t seem to function without).
The guy in front of me turned around and said, “How do you know I exist?”
I thought for a few seconds, and then said, “If you don’t, could I please cut in front of you?”
His kind, open face released a smile. He was young (probably younger than my daughters), dressed casually, wore a back-pack and those ubiquitous ear-buds — one in and one out (he’d politely popped out the left ear-bud — the one closest to me —before beginning the conversation): a student from the university, I assumed — probably fresh from a philosophy seminar.
“”No, he said; “but, if you don’t mind, could you please answer the question? It’s for a paper. I’m doing a random study of responses.”
I hadn’t noticed at first, but he was holding something in his hand: I pointed at it and asked if he was recording.
“Oh. Sorry.” He started to put it away, but I told him it wasn’t a problem: I was just curious (for no particular reason, I think I was flattered).
“So,” he said, “how do you know I exist?”
“You’re here in front of me, talking, and I can touch you” (I poked him, gently, with my index finger); “so, to me, you exhibit tactile, sensual reality.”
“I could be a figment of your imagination.”
“I suppose. But you still exist, even as a figment.”
“How so?”
There was a pause in our conversation while we ordered our drinks; but, when we’d both received our order, we sat down and continued where we’d left off…
“You exist,” I said, “even as a figment of my imagination. If you think about it, a thought has existence: it is. It was imagined, uttered, or otherwise brought into being.”
He looked at me, into me, almost through me, as if opening to the conversation for the first time, and said, “But that’s not corporal existence.”
“True. But I think we have to define what we mean by existence. Is it the world we are sensually aware of, but exists independent of our senses? Or is it everything that is? And if it’s the former, then how can I be sure of anything? Does anything exist independently of me? It reminds me of the Schrödinger’s cat dilemma.”
He said, “Could you explain?” I was suddenly sure he’d end up being a psychologist.
“Theoretical physicists — quantum mechanics — determined that the observer is part of the experiment. For example, in our current experiment, I’m attempting to determine if you are real; if you exist. Correct?”
He nodded.
“So. While I’m looking at you — or sensing you in some manner — you exist. In my universe, you exist; at the very least, you are a figment of my sensual imagination. I could ask for confirmation from any other person in this place, and I’m sure they would say that you are real, and exist — unless they are in your philosophy class, or they are being inane — because they are also part of my sensual construct. Agree?”
He glanced around, but again he nodded (and I saw him checking to make sure he was recording).
“But,” I said, “if I walk away, out of eye-sight, do you still exist? I don’t think there is any way for me to corroborate that, because I am no longer an observer in that particular experiment. I could walk back and check to see if you were still here, but that makes me an observer again. As soon as I stop sensing you, the experiment — for me — is untenable.”
“What if you see me in a photograph?”
I pondered for a moment before answering, and then said, “The picture isn’t you; however, it would exist. Anything within my sensual environment — the sphere of perception that flows about me — is part of what exists for me, whatever ‘me’ is. After I leave this coffee shop, the exchange we’ve had — and, in particular, my memory of you — will exist in my mind, in my sphere of sensual memories, but the memory is not you. My perceptions are all I can be sure of. Even though it’s an imperfect awareness, my perceptions are all I’ve got; some days I see a little clearer than others, but it suffices.
“And by the way,” I said, “how do you know that I exist?”
We talked while we finished our coffees, and a bit after that. I continued to dance around the topic, pretending to know what I was talking about. He took some books from his pack and spread them on the table. We had a pleasant existential discussion, as full of fluff as they come (with a troubling foray into Sartre’s Nausea, which has always made me uncomfortable), but he was really geared up for it.
After a while, at a convenient break in the conversation, I decided I should get moving and stood up to leave; we said our farewells and I walked away, out of sight.
A nagging curiosity got the better of me and I retraced my steps back to the coffee shop.
But he was no longer there.