One of the standard devices philosophers use to explore consciousness is the philosophical zombie. My zombie is something that looks just like me, acts like me, and in every case would do whatever I would do—except it has no conscious experience. So at Christmas my zombie would read the story from Luke and get all teary-eyed. It would go for runs and in those cases where I might speed up or slow down or take a new turn and explore routes it would do the same. If it were teaching a class it would pause in the exact places I would, make mistakes in pronunciations, and in every situation it were placed it would do what I would do—except it has no sensual experience at all. No thoughts. Nothing. Philosophical zombies (and that’s the last time I say ‘philosophical’ zombie, now they are just zombies so don’t think of Night of the Living Dead anymore) have their roots in the world—sort of. That’s where they get their power as thought experiments.
Is there anything like zombie in the real world?
First blindsight. Blindsight is a condition where someone is genuinely and truly blind, but nothing is wrong with her eyes. Somewhere there is a breakdown between the brain’s processing of sight and the sight being doled out to consciousness, but somehow the brain, at some level, still has the information. So if you show this person a set of keys and say, ‘What am I holding?’ She’ll say, “I don’t know. I’m blind.” So you say, “Well, just guess.” She pauses and looks thoughtful and says, “Keys.” Then you ask her, “What color are they?” (Let’s say they are red so that Mary in our last post can’t see the color!) She says, “I don’t know. I’m blind remember.” “Guess.” “Ok, ummmmm, They’re red.” So here is a real-world example of someone without conscious sight but they are good at guessing what they should be seeing.
So let’s imagine a more extreme version of this. A Zombie-sighted person would be someone who is really, really good at this. He could move completely as a seeing person, but without any conscious sight at all (as far as I know this is just a philosophical construction and no real ones exist). He would just intuit everything. He would reach for a glass of water, drive grandma to the doctor’s, and shop for the groceries (even compare the ingredients between two spaghetti sauces and intuit that this one had basil and the other did not). All the while just sort of guessing what to do. He might even stand in front of a sunset and say, “I can’t see what’s in front of me, but I know it’s a sunset filled with fiery red, ardent yellows, and I know it is absolutely beautiful. Maybe the most beautiful sunset I’ve never seen.”
So extrapolating this even further, to the extreme even, the philosophically complete zombie is someone who does all this without any conscious experience at all. Nothing. The lights are on but no one is home.
The other place zombies get some purchase as thought experiments is from is sleepwalkers. These people are not dreaming. They aren’t in REM sleep, they are out big time. No consciousness at all (You are actually conscious in REM sleep, but in a rather different kind of consciousness.) But they can do all kinds of things like go for a drive. Rearrange the furniture. Rake the leaves. Whatever.
So you take blind sight, add sleepwalking, and you can imagine a world where inhabitants do everything humans do, but don’t have conscious experience. They are truly Cartesian machines. Let’s imagine this world is just like our world. Exactly. I’m there, you are there, in zombie form. Your zombie goes to see Star Wars and raves about Jar-jar Binks as one of the most complex characters ever created in film literature. These zombies argue about evolution and creation. They have elections and elect people and act joyous when their candidate is elected, and say sorrowful things when their candidate looses, but they feel nothing. When music is played they dance. They are just like our super blindsighted person except, they are blind to all sensation–more complete in the totality of what they are blind to. Blind to everything we associate with consciousness.
If you ask them if they are conscious they will look at you like something is deeply wrong with you, raise an eyebrow, and say “Of course, are you?” If you ask them if they can perceive the ineffable sense of what it’s like to see the color red, they will look thoughtful and say, “I just can’t describe the beauty and wonder of the color I am seeing.” Of course these are just behaviors they go through when confronted with such questions, there is, by stipulation, no experience of red or any other color. They do have our complete behavioral repertoire however.
Is such a world possible? Physically? Logically? Can you imagine such a world? More important to this post: From a scientific perspective how would you tell our world and their world apart? Well how would you? Really. How would you?