In a prior article I laid out the major approaches to the philosophical problem of consciousness. I dwelled especially on different forms of panpsychism. Because it is a less familiar approach, many philosophers have resisted even taking it seriously. In this piece I will address what might be the more immediate reactions against it, even as a general approach.
For me, the most parsimonious solution to the mind-body problem is a bottom-up, constitutive, and parallel form of panpsychism. With such an approach, nothing in the world itself must be obviously ignored, including the existence of objects and our own subjective feelings, and no mysterious connections must be bridged. This will be my assumption for the following discussion of four likely objections.
Objection 1: Incredulity
Third, we must address the basic weirdness of imagining objects to possess any sort of individuality or consciousness. This would not seem so weird to all people at all times, but it clearly is weird to Westerners, and incredulity at the basic idea of panpsychism is common. Even if someone can imagine "what it is like" to be a bat, or perhaps even a carrot plant, the imagination fails at a rock or a quanta. And further, there is no direct evidence for panpsychism, in detectable wide-spread enmindedness. Some would say Occam's razor thus forces us to ignore the idea.
The Alternatives Are Also Weird
One important response, from an argumentative standpoint, is to contrast the weirdness demanded by panpsychism with the weirdness that is, in fact, demanded by all other positions -- given a good faith attempt to ignore their familiarity. Idealism explains consciousness as basic, but demands the rejection of all evidence of genuine physicality. Dualism creates two substances where one might do (and we might point out the anthropological peculiarity of making this move), and then leaves us asking how they could possibly communicate or interact. Materialism demands that either your subjective experience is an "illusion" of some kind, or a magical kind of radical emergence that creates subjectivity out of matter which possesses absolutely none of its features.
In all these cases, something we directly experience must be waved away, or magical explanations must be asserted or hoped for. Panpsychism accepts the evidence of human life, and does not invent anything radically new. Rather, it requires an assumption of universality -- which we are quite inclined to do regarding physics and chemistry -- and more modest forms of emergence regarding specifically human thought patterns. At worst, panpsychism demands positions that are just as weird as any other stance on mind-matter; at best, it may demand unfamiliar but ultimately less radical ones.
Maybe it's Just Inconvenient
A second response to personal incredulity about panpsychism deals with the root motives for that incredulity. I think it's significant that panpsychism may entail strong criticism of modern, Western life. Notably, it would further dethrone humanity as the lone sentience, and lone ethical entity, on the planet. Supposedly, materialism already did this, but in fact we have hung on to a practical dualism -- by assuming that an (emergent) quality grants humans agency, while only giving a few lesser traits (like the ability to feel pain) to "lesser" animals. While panpsychism can allow us a unique identity, it brings us closer to animals -- and it does not stop there. Full acceptance of panpsychism would connect us with all matter, and I think would help justify a much fuller concern for the biosphere. That conflicts quite directly with a techno-materialist economy, where everything is at our disposal.
Objection 2: Combination
First, the combination problem is the technical bug-bear of panpsychism. Human-like minds, each with with a (subjectively) singular nexus of experience, must somehow be created out of a multitude of smaller "minds" that make it up.
In some ways, I think this appears difficult because of our unfamiliarity with thinking about subjectivity, as opposed to physics. We take it for granted that molecules (and smaller particles) may combine and behave as whole objects: even though a chair is made up of wood molecules, it has, as a whole, position and velocity, etc. We can imagine an equivalent kind of acting-as-one combination occurring with subjectivity. It would happen simultaneously with chemical bonding, etcetera, and this is the radical mental shift needed to embrace parallelism: all apparently "physical" laws are subjective laws as well, for there is an identity between those sets of properties. Thus, the description of a particle "obeying" physical law is equivalent, and could be replaced by, a description of the particle having inherent tendencies of a subjective character, which it expresses.
Objection 3: Determinism
The second issue arises specifically from parallelism. Some people will be uncomfortable with the identification of physical with experiential because it would apparently make subjectivity describable by (deterministic) physical laws. This would mean that we could control what a billiard ball experiences by hitting it one way, and not another, with perfect accuracy. And a further conclusion might be that humans could be similarly manipulated.
However this is both a trivial observation and an over-simplification. It is trivial because all humans are obviously manipulable: no one can choose, by some mystical agency, to avoid feeling pain. Our environment affects us, in ways we have little control over.
But we also know that humans are more complex than a billiard ball, and so are much harder to predict, from a practical standpoint. Theoretically, if Western science is ever able to predict brain function, body function and environment, then indeed it may be able to make correlative statements about subjective states. But this is just what emergentist materialists say now, so I we haven't lost anything by switching to panpsychism.
We have gained something with panpsychism though, because with materialism we would insist that seeing all relevant brain data would somehow be an account of subjectivity, which it plainly is not. With panpsychism, we can actually ask the further question of what the physical side of the coin represents internally (subjectively) -- we would acknowledge that there is more than what is externally measurable.
We may also posit a kind of "complicated parallelism" which would incorporate complex systems and chaos theory. If single-locus subjectivity can be sustained in a complex object, we must assume -- as for ourselves -- that the precise mental state is contingent on innumerable small activities within the whole (since we are not uniform in structure, like a crystal). Therefore, very small changes, which can cascade and multiply, may reflect radically different perspectives. A magical, god-like measuring capacity could capture this complexity and sensitivity to detail, but in all practicality, prediction or control would be impossible.
I personally do not require this story, but it is a conceivable defense for the squeamish. And this is without even discussing quantum mechanics, which might also provide some reasonable escape from deterministic behavior: one might hope that "free will" is somehow hidden in quantum wave collapse. I would not hang anything on this idea, but it could also be true.
Objection 4: Ethical Nihilism
The fourth objection to panpsychism comes from a chain of arguments about moral agents. It beings by reasoning that if a thing has sentience (of any sort), that thing gains full moral status. This would mean that the total "amount" of moral entities is essentially constant in the universe: they can be reorganized or combined, but not really created or destroyed. Therefore, there are no morally preferable states: a dead human body still has "conscious" particles making it up, so is not preferable to a living one. Actions thus have no moral effect, ergo nihilism.
I do no see the initial assumption to be necessary at all, however. Even with ourselves, our mere existence is not the end of moral consideration, but the beginning: experiences and differing states matter. I prefer to be not in pain, than in pain. Equivalent moral logic should carry over to all other entities -- which need not be morally equivalent in importance.
A second kind of nihilism might nonetheless be feared. With humans we have a direct kinship with anyone who's moral status we would consider -- and we can imagine something of what they would prefer -- whereas this is not possible with a rock or a quanta. The alienness of other objects may create impossible barriers to making moral judgments about them. This could lead to a kind of practical, shoulder-shrugging nihilism.
However, I would say this scenario is not very different from our position now, under materialism: most actions are assumed to be morally neutral, with no strong reason to think any moral agent will be harmed one way or the other. It is only when we know of a preference or general rule that we feel compelled to think morally. Under panpsychism, we might have to excuse ourselves from moral mistakes on the basis of (fundamentally unattainable) knowledge -- but this is also already what we do: if innocently kicking a stone inadvertently (and improbably) leads to someone tripping and breaking an ankle, we do not feel guilty about it.
You may also note that all of this discussion rest on a fairly utilitarian basis for ethics. Panpsychism may be a fairly neutral position for utilitarianism, which depends on judgments about preferences, pain, and pleasure; but preference per se and pain per se may well be restricted to humans and some animals. Thus panpsychism does not alter normal utilitarian calculus.
But we are not really restricted to utilitarianism. If panpsychism is to give us anything on the ethical front, it will be a lot more complicated than merely extending utility-analysis to all objects anyway -- I hope it may lead to quite different starting points from which to make choices. There is no fully fleshed-out panpsychist ethical system yet to judge, but we can still reject some (misplaced) objections to one: there is no reason panpsychism should lead to nihilism.
Any viable panpsychist philosophy has some major difficulties to overcome. But so does every other answer to the mind-body dilemma -- what's more, they've been at it a while, trying to resolve their difficulties without much luck, and panpsychism at least deserves the same chance. It may be unfamiliar to us, but actually does not demand any weirder positions than what we are used to. And it may hold promise for addressing consciousness much more fully than any alternative.