CHAPTER 9
THOUGHT EXPERIMENTS ON THE MIND
Minds are simply what brains do.
When intelligent machines are constructed, we should not be surprised to find them as confused and as stubborn as men in their convictions about mind-matter, consciousness, free will, and the like.
Who Is Conscious?
The real history of consciousness starts with one’s first lie.
Suffering is the sole origin of consciousness.
There is a kind of plant that eats organic food with its flowers: when a fly settles upon the blossom, the petals close upon it and hold it fast till the plant has absorbed the insect into its system; but they will close on nothing but what is good to eat; of a drop of rain or a piece of stick they will take no notice. Curious! that so unconscious a thing should have such a keen eye to its own interest. If this is unconsciousness, where is the use of consciousness?
We have been examining the brain as an entity that is capable of certain levels of accomplishment. But that perspective essentially leaves our selves out of the picture. We appear to live in our brains. We have subjective lives. How does the objective view of the brain that we have discussed up until now relate to our own feelings, to our sense of being the person having the experiences?
British philosopher Colin McGinn (born in 1950) writes that discussing “consciousness can reduce even the most fastidious thinker to blabbering incoherence.” The reason for this is that people often have unexamined and inconsistent views on exactly what the term means.
Many observers consider consciousness to be a form of performance—for example, the capacity for self-reflection, that is, the ability to understand one’s own thoughts and to explain them. I would describe that as the ability to think about one’s own thinking. Presumably, we could come up with a way of evaluating this ability and then use this test to separate conscious things from unconscious things.
However, we quickly get into trouble in trying to implement this approach. Is a baby conscious? A dog? They’re not very good at describing their own thinking process. There are people who believe that babies and dogs are not conscious beings precisely because they cannot explain themselves. How about the computer known as Watson? It can be put into a mode where it actually does explain how it came up with a given answer. Because it contains a model of its own thinking, is Watson therefore conscious whereas the baby and the dog are not?
Before we proceed to parse this question further, it is important to reflect on the most significant distinction relating to it: What is it that we can ascertain from science, versus what remains truly a matter of philosophy? One view is that philosophy is a kind of halfway house for questions that have not yet yielded to the scientific method. According to this perspective, once science advances sufficiently to resolve a particular set of questions, philosophers can then move on to other concerns, until such time that science resolves them also. This view is endemic where the issue of consciousness is concerned, and specifically the question “What and who is conscious?”
Consider these statements by philosopher John Searle: “We know that brains cause consciousness with specific biological mechanisms…. The essential thing is to recognize that consciousness is a biological process like digestion, lactation, photosynthesis, or mitosis…. The brain is a machine, a biological machine to be sure, but a machine all the same. So the first step is to figure out how the brain does it and then build an artificial machine that has an equally effective mechanism for causing consciousness.”1 People are often surprised to see these quotations because they assume that Searle is devoted to protecting the mystery of consciousness against reductionists like Ray Kurzweil.
The Australian philosopher David Chalmers (born in 1966) has coined the term “the hard problem of consciousness” to describe the difficulty of pinning down this essentially indescribable concept. Sometimes a brief phrase encapsulates an entire school of thought so well that it becomes emblematic (for example, Hannah Arendt’s “the banality of evil”). Chalmers’s famous formulation accomplishes this very well.
When discussing consciousness, it becomes very easy to slip into considering the observable and measurable attributes that we associate with being conscious, but this approach misses the very essence of the idea. I just mentioned the concept of metacognition—the idea of thinking about one’s own thinking—as one such correlate of consciousness. Other observers conflate emotional intelligence or moral intelligence with consciousness. But, again, our ability to express a loving sentiment, to get the joke, or to be sexy are simply types of performances—impressive and intelligent perhaps, but skills that can nonetheless be observed and measured (even if we argue about how to assess them). Figuring out how the brain accomplishes these sorts of tasks and what is going on in the brain when we do them constitutes Chalmers’s “easy” question of consciousness. Of course, the “easy” problem is anything but and represents perhaps the most difficult and important scientific quest of our era. Chalmers’s “hard” question, meanwhile, is so hard that it is essentially ineffable.
In support of this distinction, Chalmers introduces a thought experiment involving what he calls zombies. A zombie is an entity that acts just like a person but simply does not have subjective experience—that is, a zombie is not conscious. Chalmers argues that since we can conceive of zombies, they are at least logically possible. If you were at a cocktail party and there were both “normal” humans and zombies, how would you tell the difference? Perhaps this sounds like a cocktail party you have attended.
Many people answer this question by saying they would interrogate individuals they wished to assess about their emotional reactions to events and ideas. A zombie, they believe, would betray its lack of subjective experience through a deficiency in certain types of emotional responses. But an answer along these lines simply fails to appreciate the assumptions of the thought experiment. If we encountered an unemotional person (such as an individual with certain emotional deficits, as is common in certain types of autism) or an avatar or a robot that was not convincing as an emotional human being, then that entity is not a zombie. Remember: According to Chalmers’s assumption, a zombie is completely normal in his ability to respond, including the ability to react emotionally; he is just lacking subjective experience. The bottom line is that there is no way to identify a zombie, because by definition there is no apparent indication of his zombie nature in his behavior. So is this a distinction without a difference?
Chalmers does not attempt to answer the hard question but does provide some possibilities. One is a form of dualism in which consciousness per se does not exist in the physical world but rather as a separate ontological reality. According to this formulation, what a person does is based on the processes in her brain. Because the brain is causally closed, we can fully explain a person’s actions, including her thoughts, through its processes. Consciousness then exists essentially in another realm, or at least is a property separate from the physical world. This explanation does not permit the mind (that is to say, the conscious property associated with the brain) to causally affect the brain.