You have one minute to explain the taste of a tomato without using the word “tomato.” I’m waiting.
And, did it work? That’s what I thought. Human vocabulary, plain and simple, just is not enough to accurately describe the flavor of a tomato, pineapple or any other food. The attempt is just as destined to fail as trying to explain the color “red” to a born blind person. An integral part of any sensory perception is a wholly subjective, personal sensation, known as “qualia” in the jargon of consciousness research.
The subject of consciousness continues to reside on the periphery of the humanly explicable and possible, similar in caliber to a question such as: “What exists outside of the universe?” Experiencing qualia, that is, subjective experience at all, is a strong indicator of the existence of our consciousness. Only a conscious subject can experience subjectively. Consciousness, however, has yet to be accounted for, that is, measured, empirically. It comes as no surprise that qualia have created a wide gulf in science. While some completely deny their existence, others regard them as an indispensable component of our world.
What distinguishes qualia is their non-communicability. They exist only for an individual. Of course, we are able analyze and describe the exact wavelength of red or the biochemical composition of pineapple, yet that only pertains to our external mechanisms of perception. More interesting is what happens after the information has been gathered and processed by our nerve receptors, after the neurons have fired. In other words: why do we have subjective visual and flavor experiences? Or: do we actually have them? How can something so obviously physical like the brain generate something as non-physical as sensations of taste or color, or most basically, the feeling of “being”? Let’s take one thing at a time.
How does a flavor come about anyway? Most would say, “That’s easy. Via the taste buds on our tongue.” To a certain extent that’s true, yet it’s also not that simple. Human color perception is a good comparison, as nothing in the world is in itself colored. The colors we see every day arise in our brain. By extension, the same logic could apply to our palate. And here’s where it’s all taken to the next level. Looking at modern robots as an example, which can among other things “taste,” it becomes evident that these machines, just like us, differentiate, analyze and describe flavors. Even so they do not have a subjective perception of taste, no “taste experience.” Of course, these machines are not as intelligent as we are, and this is of no further consequence to elaborating this train of thought. Even if they were they would not be able to sense qualia given the current scientific knowledge. So a certain component seems to be missing.
Here things get tricky, as it is precisely this component that makes the whole problem so complicated. The thought experiment of the “philosophical zombie” serves as a good illustration. Imagine an organism that resembles humans in every way. It can walk around, converse, go out for ice cream and even say things like, “I have a conscious mind.” But the difference is that it actually has no consciousness. I think anybody can image that without much difficulty. Of course you can never say with certainty whether your counterpart really has consciousness, which would imply that consciousness and qualia are something that can, or even have to, exist independently of the physical body. Provided you accept the premise, “What is conceivable is possible.”
One of the most popular critics of the idea of qualia is the cognitive scientist, Daniel Dennett. In his paper, “Quining Qualia” he attempts to debunk qualia as a figment of our imagination. According to his materialist perspective the enigma of consciousness must be solved on a purely physical level. His view of the world does not go beyond receptors, neurons and synapses. We are part of the physical world, and according to Bennett the same applies to our consciousness. The philosophical zombie he regards as a symbol of the human need for recognition. Were the zombie to exist, our consciousness would be characterized by a kind of supernatural substance – something unbound to our body that could possibly exist beyond our death. You could call this a “soul.” Without said “soul” we would just be matter. What we sense while eating a tomato would just be a specific combination of receptors on our tongue and neurons in our brain firing in a certain way, evoking memories of previous tomatoes and other information we associate with tomatoes in our prefrontal cortex. An unbearable thought for many people.
Following Dennett’s approach, the entire universe and everything we see around us are the products of a soulless process without purpose. As for qualia, Dennett is a minority of one with his radical thesis. Many consciousness researchers regard the existence of qualia as highly plausible.
Richard Gregory, a cognitive psychologist at the University of Bristol is completely convinced by the notion of qualia and claims to have identified their function. How they come into being, however, baffles him too. To be able to orient ourselves in the world and understand it our brain is constantly drawing on a massive bank of experiences in our subconscious. If, for instance, I want to eat an orange, my brain has to remember that I cannot eat the rind. With everything we perceive our brain has to process enormous amounts of data so we react appropriately to our environment. According to Gregory, qualia could function to signal the present to the brain, enabling it to separate the past and “now” from one another. Dreaming is a good example of this. Regardless of how real the dream is, as soon as we wake up we know with absolute certainty that we are back in reality. Qualia, or absolutely subjective sensory experiences, would not only make our lives more worth living; they would be essential for survival.
Tomato is a tomato is a tomato is a tomato. If only.
Images: Eugenia Loli