“Explanations of consciousness abound and the radical diversity of theories is telling. Explanations, or theories, are said to work at astonishingly divergent orders of magnitude and putative realms of reality. My purpose here must be humble: collect and categorize, not assess and adjudicate. Seek insights, not answers.

Unrealistically, I’d like to get them all, at least all contemporary theories that are sufficiently distinct with explanations that can surmount an arbitrary hurdle of rationality or conceivability. Falsification or verification is not on the agenda. I’m less concerned about the ontological truth of explanations/theories than in identifying them and then locating them on a “Landscape” to enable categorization and assess relationships. Next, I assess implications of categories for “big questions.” Thus, this Landscape is not about how consciousness is measured or evolved or even works, but about what consciousness is and what difference it makes.

It’s the classic “mind-body problem:” How do the felt experiences in our minds relate to the neural processes in our brains? How do mental states, whether sensory, cognitive, emotional, or even noumenal (selfless) awareness, correlate with brain states? The Landscape of Consciousness explanations or theories I want to draw is as broad as possible, including those that cannot be subsumed by, and possibly not even accessed by, the scientific method. This freedom from constraint, as it were, is no excuse for wooly thinking. Standards of rationality and clarity of argument must be maintained even more tenaciously, and bases of beliefs must be specified even more clearly.

I have two main aims: (i) gather and describe the various theories and array them in some kind of meaningful structure of high-level or first-order categories (and under Materialism, subcategories); and (ii) assess their implications, with respect to four big questions: meaning/purpose/value (if any); artificial intelligence (AI) consciousness; virtual immortality; and survival beyond death.

Theories overlap; some work together. Moreover, while a real-world landscape of consciousness, even simplified, would be drawn with three dimensions (at least), with multiple kinds and levels of nestings—a combinatorial explosion (and likely no closer to truth)—I satisfice with a one-dimensional toy-model. I array all the theories on a linear spectrum, simplistically and roughly, from the “most physical” on the left (at the beginning) to the “least physical” on the right (near the end). (I have two final categories after this spectrum.) The physicalism assumed in Materialism Theories of consciousness is characterized by naturalistic, science-based perspectives, while non-materialism theories have various degrees of nonphysicalist perspectives outside the ambit of current science and in some cases not subject to the scientific method of experimentation and replicability.

Please do not ascribe the relative importance of a theory to the relative size of its description. The shortest can be the strongest. It sometimes takes more words to describe lesser-known theories. For each description I feel the tension between conciseness and completeness. Moreover, several are not complete theories in themselves but ways to think about consciousness that strike me as original and perhaps insightful.

I have followed consciousness studies in its various forms for my entire life. My PhD is in neurophysiology (thalamocortical evoked potentials). I am creator and host of Closer To Truth, the long-running public television series and web resource on science and philosophy, roughly one-third of which focuses on consciousness and brain/mind topics. I have discussed consciousness with over 200 scientists and philosophers who work on or think about consciousness and related fields (Closer To Truth YouTube; Closer To Truth website).

I use these Closer To Truth discussions as resources. I want to give feel and flavor, as well as propositions and arguments, for the astonishingly diverse attitudes and approaches to consciousness coming from radically diverse perspectives and worldviews. That’s why I use spontaneous quotes from verbal conversations along with meticulous quotes from academic papers.

In one early Closer To Truth episode, “What are the Big Questions of Science,” philosopher Patricia Churchland gave the bluntest answer: “Out of meat, how do you get thought? That’s the grandest question.” She distinguishes two major questions. One is whether psychological states—our mental life of remembering, thinking, creating—are really a subset of brain activity? The other is how do high-level psychological processes come about from basic neurophysiological actions? “How do brain cells, organized in their complex ways, give rise to my watching something move, or seeing color, or smelling a rose”(Churchland, 2000).

Philosopher David Papineau distinguishes three questions related to consciousness: How?, Where?, and What? “First, how does consciousness relate to other features of reality? Second, where are conscious phenomena located in reality? And, third, what is the nature of consciousness?” (Papineau, 2020a). Because this Landscape is structured by theories of consciousness, not by philosophical questions, each theory sets its own agenda for dealing with the three questions, mostly, of course, focusing on the How?

Philosopher Thomas Nagel sees more a fundamental conundrum and he frames it crisply. “We have at present no conception of how a single event or thing could have both physical or phenomenological aspects, or how if it did they could be related” (Nagel, 1986). In his influential paper, “What Is It Like to Be a Bat?,” Nagel offers, “Without consciousness the mind-body problem would be much less interesting. With consciousness it seems hopeless” (Nagel, 1974).

“Hopeless,” to me, is invigorating; I’m up for the “hopeless challenge.” Take all that follows as my personal journey of consciousness; idiosyncratic, to be sure; not all for everyone, not set in cement.”

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