Consciousness is a philosophically "hard problem." Ordinary scientific progress -- in psychology or neuroscience, say -- do not seem capable of addressing it, even in principle. As the philosophers Thomas Nagel and David Chalmers argue, normal science cannot grapple with "what it is like" to be something; subjective experience stands quite apart from science's (reductive) explanations. This may make consciousness more of a philosophy problem than a scientific problem.
Various thinkers have imagined many explanations for consciousness, and it would behoove any educated person to consider them. Despite their number, they fall into a handful of large groups, which I will lay out here. I hope this can help you think through them -- and in particular consider one oft-ignored option, panpsychism.
Consciousness of a subjective, inner sort seems to be fundamentally different from physical substance. So what is it? There are four main ways to answer this, varying with how many fundamental susbtances are posited:
|Dualism||2: Matter, Mind|
Each position is limited in the ways it can try to explain consciousness, and each faces its own fundamentally "hard problem."
Materialism is the basic foundation of science and, arguably, Western thought generally. Consciousness is supposed to arise naturally from the right combination of matter, e.g., human brains. How exactly this happens is the hard problem: radical emergence of experience from non-experiencing material. Supporters generally assume that some detailed description will be forthcoming, but I think Thomas Nagel argues persuasively that there's no great reason to be optimistic about this -- and that all the "solutions" put forward so far are essentially hand-waving.
(In anticipating some satisfactory story for emergence, many materialists view consciousness as a mere epiphenomenon, where it is caused by matter but not vice-versa. Some, such as Daniel Dennett, also dismiss consciousness as more-or-less an illusion. I find this an overly-convenient omission of first-hand evidence.)
Idealism holds the reverse of materialism: subjective thoughts are ultimately what is real, and matter is merely a projection, perhaps of a universal mind we all participate in. Consciousness itself is not a problem here, but one must take the fairly radical position of rejecting sensory information as any kind of guide to reality. The truly hard problem may be elsewhere though: one must explain how different minds coordinate a shared delusion, or how a single world mind is divided into multiple experiencing entities. Although popular in eastern religions (some kinds of Buddhism) and esoteric traditions, I find idealism a tough road to travel -- at least if one wants to understand the world we find ourselves in.
Dualism posits mind and matter co-existing separately. It has been popular in the Christian West, with souls the seat of individual consciousness and will. But despite a lot of effort by Renaissance theologians, dualism's hard problem persists: how can mind influence matter -- or vice-versa -- if they are truly separate? I would also make a pragmatic case against dualism for devaluing non-human life and our planet generally. (One may say the same of materialism, but drawing the distinction is difficult: I think most Americans are materialists by day and dualists on Sunday.)
Neutral Monism accepts physicality and mentality as real, but holds that they must ultimately be aspects of a single substance which makes up the universe. This requires that some kind of consciousness be present in everything, including apparently non-cognizant things like helium gas. (I discuss whether this is an incredible position to take below.)
One way to get a permeating mentality is a world-consciousness that gets divided up into parts. Another is the presence of consciousness down at the smallest levels of organization, like quarks. In either case, you have a hard problem getting consciousness back to the level of human awareness (where we know it exists): either in dividing it away from the ur-mind, or in combining elementary consciousnesses together. It is not obvious how either might happen.
While the positions above concern the existence of consciousness at a fundamental level, another, distinct, topic concerns where and how subjective experience is actually instantiated in the world. That is, what gets to experience experiences? (This is technically independent of the prior question, but various positions do tend to go together.)
Emergence suggests that certain physical arrangements of things will generate subjectivity spontaneously, thanks to the natural laws of the universe. Only a few, special entities are likely to have this arrangement, for instance as a result of evolution. This is the choice most materialists take today.
Special status is invoked by some theologies to grant a few entities minds, but not others, as in protestant Christianity. Since there is no real explanation possible for this, I will not discuss it further.
Panpsychism says that mind is ubiquitous and found throughout the universe, rather than arising in any particular time or place. Although idealist panpsychists are possible, most currently seem to be neutral monists.
The hard problems of both emergence (especially with materialism) and dualism have been discussed endlessly with little resolution, and I would argue that both have caused a great deal of harm by devaluing the non-human world around us. Although some people are comfortable with idealism, it seems to give up on explaining the world. Therefore, panpsychism remains an under-discussed option, and would seem to deserve another chance. The remainder of this article will therefore be concerned with neutral-monist panpsychism.
Many varieties of panpsychism have been put forward. We can distinguish them partly by how they answer each of three questions.
Bottom / Top / Field
The first question is "where" we see consciousness entering the picture. In the bottom-up approach, even the most elementary particles of the world have consciousness in some degree or form, and they combine to create more self-aware entities like humans.
In a top-down model, there is a singular world intellect somehow divided into individual subjects (at least sometimes), as in the case of humans.
Finally, we can imagine consciousness to be elementary but not associated with particular objects; rather, it is a field that permeates the background existence of the universe. If this field is held to be essentially identical with a divine agent, then we are really speaking of pantheism instead of panpsychism, which is rather more about the abilities of things in this world (however, perhaps the two positions can be held simultaneously).
Constitutive / Emergent
A second question specifically concerns conscious entities that have "higher" features, for instance, self-awareness. In constitutive panpsychism, the combination of semi-conscious sub-units directly creates things like human minds, more or less additively.
In an emergentist view, mere agglomerations of sub-units are not enough; some special arrangements must also be necessary to "suddenly" cause full awareness to emerge -- and the physical aspects of things may be needed as well. This, of course, suffers from the same (additional) hard problem of normal emergence.
(There is also a third option, where a single "dominant" particle in each physical entity becomes its sole seat of power and subjectivity. This has quite a few problems, which I will not go into.)
Parallel / Independent
The third questions concerns how physical and mental aspects of things are related. A parallel view takes them to be essentially intertwined, if not identical, down to the details: every physical state occurs with (or is) a corresponding mental state, and vice-versa, so that they cannot be separated. (Chalmers identified Bertrand Russel as this sort of panpsychist.) Alternately, it could be that mental and physical aspects exist independently. A problem with this is, again, how they will interact and have causation on one another.
All of these options have their difficulties, and panpsychism is no exception; in fact, on its face it may seem ludicrous to many. However, I do believe it deserves serious thought, and I answer some possible objections to it in this article.