I and others have argued for the inherent incompleteness of sets of physical laws as descriptions of reality - such ladders of categorization of reality will always be missing the bottom rung. Moreover, we are confronted with a phenomenon, consciousness, that does not seem to have a natural home in the world that physics describes.
Let's imagine for a moment that the panpsychists are right, and that some kind of crumb of proto-consciousness must exist down at the lowest levels of reality, along with mass, charge, and spin. Although it is probably better to say that this crumb of proto-consciousness underlies or instantiates those other physical properties, or that it implements them willfully.
I have also argued that so-called levels of organization buy us exactly nothing in terms of explaining consciousness: all "higher-level" aggregations or black boxes do for us is allow us to think of masses of low-level parts more effectively. No explanatory power is given or taken away by thinking of the lower levels chunked up in one way or another.
So how does panpsychism get around the famous aggregation problem (sometimes also called the combination problem)? Even if at the lowest levels of physics, quarks are conscious, and quark behavior is implemented by quark consciousness, each quark is still a windowless monad, blindly knocking into other particles, interacting only by functional dynamics. The only way to scale up is functionally. Functionalism still wins, even if the bottom-most subcomponents are, in some way, conscious (or proto-conscious).
I think it would be cool to write a comic book in which the protagonist is a superhero: six foot four, barrel-chested, cape, square jaw, steely gaze. He can do anything he wants, unbound by the laws of physics, because he is an elementary particle. A big one. If you get close to him, you see that he is not made of cells, which are in turn made of molecules. He is just one big indivisible thing. He is an example of what William Seager calls a "large simple", or Galen Strawson (2009, p. 380) calls a "complex absolute unity". You've got your electrons, you've got your quarks, you've got your photons, and you've got Particle Man.
There has never been a Particle Man before, and there never will be again, so there is no existing body of laws that apply to him. Every moment of his existence, whatever he does is automatically a new law of Nature, albeit a uselessly inapplicable one - the law would apply to the one moment of its coinage, and no other. There are no existing laws that define the mass of a Particle Man, so he gets to decide what his mass is at any moment. Same with his shape and size, his interactions with other stuff, his trajectory though space-time. He can collapse himself into a singularity, or he can spread himself as a fine matter-mist throughout the cosmos. He can wink in and out of existence.
Whatever he does at any time is just what Particle Man does at that time, and as such is a law of nature with all the rock-solid authority of Ohm's law. In fact, it is only whimsy on his part that he chooses to assume human form at all. It might be a pretty boring comic book, come to think of it - Particle Man would have godlike powers, far more than those of Superman (although the Green Lantern, in some interpretations, has approached this level of power).
Surely, though, Nature, which has been so tidy and parsimonious with its elementary particles and laws up to now would not create something so extravagant as Particle Man, casting off new laws willy-nilly, every instant of every day! Possibly, but our preference for neat, tidy, elegant systems, and our certainty that everything big and tricky must be made of things that are small and simple are not binding on Nature.
I usually don't think too much about the sociology of science or philosophy, but it would be foolish to deny that these disciplines are conducted by human beings. Children and primitive societies are natural anamists, and anthropomorphizers. Hurricanes are angry. The earth loves us. Eventually, after thousands of years, and lead by a few singular geniuses, we trained ourselves in a new way of thinking. This new reductive habit of thought consists of approaching every big complicated thing as an aggregate of small simple things that behave in consistent lawlike ways. Since the time of Galileo and Newton, this kind of thinking has been spectacularly successful within its proper domain, and has lead to what is legitimately called the Enlightenment and the Scientific Revolution.
Here we are, a few hundred years later, and that revolution is still charging along, and we are all taught this way of thinking in grade school, whether we major in physics or not. We accept it as the default way of seeing the world. It is hard for us to imagine (or perhaps to remember culturally) just how hard-won and counterintuitive the relatively new reductive ways of thinking are. Training ourselves to think like this was slow and difficult at one time. We have mastered it wonderfully, but it has left us with a residual knee-jerk reaction against anything that smells even faintly like holism or anthropomorphism. Such ideas strike us as unseemly and embarrassing. Our self-imposed mental training has left us with a blind spot - even if holism is staring us in the face, we would refuse to see it. Nothing like the zeal of a convert.
Now I do not think that Particle Man exists, at least as a whole man-sized solid thing. (The idea of this superhero is a more concrete image of the kind of thing I was getting at in my chapter about free will.) Rather, I suspect that a given unitary moment of consciousness consists of a Particle Man-like blob of - something. Consciousness just can't exist in a world made of pure physics as we understand it (if a world made of "pure physics" is even a coherent idea) - panpsychism must be true. But a conservative panpsychism that posits (proto) consciousness at the lowest level and keeps it there is stopped dead by the aggregation problem. We are forced to go out on a limb and speculate as to how consciousness scales up beyond the individual physical particles.
Quantum mechanics tells us about different systems of small particles coming together into such blobs that, although born of complexes of smaller things, and destined to fall apart into subcomponents in the future, are, must be, one single thing as far as Nature is concerned. Quantum mechanics shows us real emergence, so-called radical emergence in action, not just the perceived emergence of the flock "emerging" from the birds, or the liquidity "emerging" from the motion of the molecules of water. To be useful to a full-blooded panpsychism, it doesn't have to be a whole person, and it doesn't have to be very long-lived - it just needs to be enough of a new thing to be qualitatively unique and causally efficacious on some macro scale.
Chaos theory tells us that the universe is chock full of situations in which neighbors do not map to neighbors, in which tiny differences make huge differences - the oft-cited Butterfly Effect. The panpsychist's qualitative blob would not have to be very big at all to make the kind of difference we need it to make in order to push the brain around. Not only am I not a quantum physicist, but I am also not a neuroscientist. Nevertheless, it strikes me that in our chaotic universe, a neuron would be a fine place to look for microscopic changes having macroscopic effects.