The supposedly hard problem of consciousness and the nonexistence of sense data: Is your dog a conscious being?
Of dogs and cows
Are dogs conscious? My guess, you think so: that’s why they’re termed “sentient.” We assume that dogs see the world much as we do, despite being receptive to different information; they experience the same conscious data of sense as we experience. You, nevertheless, might be prepared to concede the ultimate unfathomability of the question, but if not, consider a related question: when did consciousness first arise in the course of organic evolution?
The reason the questions are obscure deserves scrutiny. I think I know you’re conscious because you say you know what I’m saying when I mention “consciousness” or “experience,” but the limits of my knowledge of consciousness are telling: I will never find some physical structure to explain it. This isn’t due to lack of empirical research or of theoretical ingenuity. To explain an observation, you must describe it, and the language used for describing conscious experience is the same language used for describing the object the experience refers to. The most I can do to describe the experienced “brownness” is achieved by referring to its cause. When I see a brown cow, I can only describe the raw experience as “brown”: the color that ordinarily gives rise to the experience. Thus, I necessarily omit from the description exactly what I want to explain: the qualitative character of the “brown” experience.
If qualitative consciousness existed, it would be utterly inexplicable; yet, the evidence of direct experience seems self-evidently to support its own existence. This seemingly immediate awareness of our raw mental states seems to be just what it is like to be ourselves. (Thomas Nagel.) Regardless of the apparent indubitability of the intuition that we have raw experiential states, this intuition remains nothing more than belief, and beliefs are subject to illusions that mislead us systematically.
One reason you might resist the conclusion that qualitative experience is illusory is wholesale distortion of reality regarding objects of seemingly immediate awareness seems implausible just because of our intimate connection with our own experience, but scientific developments can render seemingly unrelated philosophical positions plausible. The work of neurologists, such as Oliver Sacks, should caution against the prejudice that some experiences are so basic they resist radical distortion and fabrication. An example Sacks describes is a brain-damaged patient who mistook his wife for a hat. Neuroscientists conclude that cognitive functions are assemblies of modules, making it less startling that beliefs can be so radically wrong.
There’s also a conceptual reason for the reluctance of philosophers and scientists to reject the intuition of raw sense experience: lack of clarity about how to characterize the prewired belief responsible for the illusion. The intuition seems too complex and sophisticated to accommodate innate belief; philosophers trying to nail down the precise content of the belief that qualia exist have had recourse to thought experiments remote from actual experience, and nobody seems to have characterized the essence of qualia. My suggestion: the illusion of qualitative awareness is the belief that we when we perceive or imagine objects, we have independently real experiences characterizable only by the terms used to describe the external object itself. Qualia are inherently ineffable contents of perception or imagination.
The illusion’s evolution
This definition also suggests an evolutionary explanation for the illusion of qualitative experience. Thought doesn’t depend on the illusion of consciousness, as one can easily conceive of an intelligent being without illusory beliefs about the nature of the thinking process, but the illusion of consciousness might have encouraged the development of thinking. Perhaps human ancestors evolved the innate belief that they have experiences with properties corresponding to those of their referents because this belief encouraged our ancestors to make mental models of the world—encouraged them to engage in the offline thinking unique for our species. Objectified conscious experience could encourage mental-model making by generalizing the prior insight that you can predict one external object by manipulating a similar external object. Our ancestors would then need only substitute internal objects for external ones.
Bypassing “sense data” in the theory of knowledge
According to one longstanding theory in epistemology, sense data are our only basis for knowing the external world. This doctrine, taken to its logical conclusion, leads to skepticism about the external world’s existence: sense data, supposedly our window to the world, became an insuperable barrier to cognition, for if all our knowledge is nothing but construction from sense data, our sense data are all we know. We can’t get out of our own minds.
The reason the sense data theory leads to skeptical conclusions goes back to ineffability. If we know the world by sense data, you can draw conclusions about the world only through analogy, that is, by forming a relationship between two descriptions. Ineffable sense data have nothing in common with a world of things, except their names —such as “brownness.”
This account of raw experience as an adaptive illusion brings clarity to the argument that free will is illusory. The sense of free will, I concluded, is the misperception that experienced deciding causes behavior. But “experience” doesn’t exist. Compatibilist free will is incoherent because it assumes the causal efficacy of unreal raw experience.