P-zed

P-zeds

Quantum Night

By Robert J. Sawyer

“Okay,” I said, looking out at my first year psych class, “how many of you drive to the university each morning?”

About a third of the students put up hands.

“Keep your hands up. The rest of you: How many of you have had a job you've driven to day after day?”

Another third raised hands.

“Okay, now keep your hands up if this has has ever happened. To you: you arrive at your destinations – school, work, whatever – and have no recollection of the actual drive.”

Most of the hands stayed in the air.

“Cool,” I said. “Lower your hands. Now, think about that: you undertook a complex task; you operated a vehicle weighing over a thousand kilos, you negotiated traffic, you avoided collisions, you obeyed signs and the rules of the road – you did all that without high-level conscious attention; that is, you did it while your mind was on other things.

“Let's try another one: how many of you have ever been reading a book – not one of mine, you understand, but somebody else's – and gotten to the bottom of a page and realized you had no awareness of what the page said"?

Again, lots of hand went up.

Philosopher's Zombie. Photo by Elena.

“Okay, you might argue that driving a car is an example of what laypeople call muscle memory, although the technical term is “procedural memory” - stuff you do without thinking about it, like returning a serve in tennis or playing a musical instrument. But what about the reading example? Your eyes tracked across successive line, and, on some, level, your brain was presumably recognizing and processing the words. In fact, you can contrive priming tests to demonstrate that the words were noted. If the page referenced, say, a porcupine, and you're asked, even though your mind wandered off while reading so you say you have no high-level conscious recollection of the page, to name a mammal, chances are you'll say “porcupine.” So, reading can't be dismissed as just muscle memory, just your eyes tracking without actually seeing. And yet you can do it, too, without real attention.”

I let that sink in for a moment, then went on. “So, it's clearly true that you can perform sophisticated acts without your full conscious attention some of the time. And, by logical extension, if you can do those things that way some of the time, then it's presumably possible there are people who do them that way all of the time. Of course, we'd have no way to tell, would we? When you're reading but not absorbing, nobody can tell that from the outside. And when you're driving but not paying attention, again, well, if the police had a way of detecting that by some external sign – your eyeballs rolling up into your skill, say – you can bet they'd pull you over. But there is no external indication.”

I took a sip from the coffee cup on the lectern, then went on. “And that brings us to one of the most famous thought experiments in philosophy. Imagine a being who didn't just drive all the time without paying attention, and who didn't just read all the time without paying attention, but who in fact did everything all the time without attention. An Australian philosopher, David Chalmers, is the guy most associated with this proposal. He says it's logically coherent – that is, there are no internal contradictions – to the notion that a whole planet could exist full of such entities: being for whom the lights are on but nobody's home, being who are, quite literally, thoughtless.” Another sip, then: “Anybody got a suggestion for what we should call such creatures?”

I was always happy to set that one up, and my students never disappointed. “Politicians!” called out one. “Football players,” called another.

“Well,” I said, “almost anything would be an improvement over the term we actually use. Such beings are called “philosophical zombies. Or “philosopher's zombies.” It's a terrible name: they're not the walking dead, they don't shamble along. Behaviorally, they're indistinguishable from the rest of us. Sadly, the phrasing “philosophical zombie” is more common in the literature than “philosopher's zombie,” but it doesn't make sense: the one thing such creatures are unlikely to be is philosophical. Oh, they might say things a philosopher would - “A could well follow from B,” or “Yes, but how can we be sure your experience of red is the same as my experience of red?” or “Would you like fries with that?” - but they'd only be acting like a philosopher. There would in fact be no inner life, no rumination. Me, I mostly avoid the zombie word. In the States, they can't really abbreviate “philosopher's zombie” to its initials because it comes out sounding like "peasy,” as in “easy-peasy”/ But here we can safely call them p-zeds, so let's do that from now on.”

One of the students, a muscular guy named Enzo, raised his hand. “Well, then Professor Marchuk, if all that's true – if it really is possible – then how do we know you're not a p-zed?

“How indeed?” I replied, smiling beatifically at them all.