Proving Consciousness

      The most difficult problem facing those who study consciousness is that there is absolutely no verifiable evidence that it exists. An entity cannot be identified, much less measured, unless it exerts some causative influence in our observable universe. For example, we infer the existence, and measure the magnitude of mass by observing objects’ gravitational pull on one another, and by watching Newton’s second law in action. We indirectly identify the structures of miniscule proteins by observing the way x-rays scatter when shone through their crystalline forms.
      Consciousness has never been shown to exert any causative influence on anything else. As far as we humans collectively can tell, consciousness may well be epiphenomenal, a by-product that plays no part in the ongoing integrative neural processes that generate it. The philosophical construct of the “zombie” illustrates this terrifying idea: imagine a human being who interacts with her fellow humans, talks on the phone, drives a car, shops for groceries, does her taxes, and hugs her children, but does so totally mechanically: she has no awareness and no intention. If you think this sounds impossible, you may be right (although, as I try to argue in this essay, you’d be hard-pressed to prove it), but the notion is easily conceived. Consider sleepwalkers and epileptics: though they are curiously emotionless, they do engage in complex, characteristically human behaviors. Consider the anthropic robots, ubiquitous in science fiction, that we all hope and/or fear will someday join us humans in our lonely sentience. What is it about human behavior that requires an agent, aware of herself and her environment, and intentional in her actions? If IBM’s Watson taught us anything, it’s that it might be less than we think.
      Of course, no one is content to throw her hands up in the air, conclude that consciousness is pure epiphenomenon, and then return to her life, a life that is obviously replete with subjective experiences and purposeful decisions. Consciousness, such as it is, must have some influence on the physical world. To claim otherwise would be to directly contradict our most fundamental and cherished beliefs. What is that causal connection? I don’t presume to know, but I would like to offer a glimmer of evidence that such a connection exists. The missing link must satisfy two criteria: it must have tangible consequences, and it must not be possible that anything other than consciousness produced it.
      I’m writing this essay surreptitiously as I sit in the back of a departmental seminar. The speaker is a friend of mine, a fellow graduate student who studies the psychology of language. She is quirky and inquisitive, with a flair for asking the type of questions that should have been obvious, but that no one has thought to ask. In other words, she is intelligent, emotional, and quite obviously conscious, but I am not privy to the contents of her consciousness. For all I can prove it, she might be a zombie.
      On the other hand, I am privy to the contents of my own consciousness. Again, I can only convey it linguistically: you will never taste my experience. But I do. I may misremember it; I may misunderstand it and misinterpret it and misrepresent it to you now, but I am aware of a conscious experience. Even if my consciousness is an illusion, that illusion itself must be a conscious experience! This has nothing to do with what I can report, a common criterion for consciousness in cognitive psychology. It has everything to do with what I know, and I know, more surely than I could possibly know anything else, that experience is happening.
      That knowledge is the missing link. It has tangible consequences: you’re reading them. And it was caused by consciousness: even an illusory experience is an experience. Unfortunately, I cannot prove this to you - a sufficiently advanced algorithm could conceivably have produced this essay – but I can invite you to experience it for yourself.