In the interests of exploring every metaphysical option, I will consider the doctrine of temporal panpsychism. Several positions on time may be distinguished: materialism, idealism, functionalism, mysterianism, and panpsychism. Materialism says that time reduces to physical objects or processes: clocks, whether natural or man-made, or possibly physical processes such as entropy. Idealism says that time reduces to experiences of time—human consciousness, basically. Functionalism says that time is whatever it is that plays a certain role, notably functions as the medium for change and events. Mysterianism says that time is something whose intrinsic nature transcends our knowledge, though we know that it exists and can be measured. Panpsychism says that time has an inherently mental reality, possibly quite different from our own mental reality—a kind of free-floating river of mental being. Idealism identifies time with human consciousness of time; panpsychism identifies time with a specifically temporal form of consciousness existing independently of human consciousness (or that of any other sentient being). These positions are all analogues of positions with which we are familiar in regard to matter and space; in particular, temporal panpsychism is the analogue of material and spatial panpsychism. Just as it is thought that matter has a hidden mental nature, and that space has a mental nature too, so it is contended by the temporal panpsychist that time has a hidden mental nature. That is, wherever there is time there is a certain kind of mental stuff that constitutes it. We are not normally aware of the nature of this mental stuff (but see below) yet it is real nonetheless—it is part of objective reality. And it performs two explanatory jobs: it is the foundation of mind as we and other animals experience it, and it furnishes a substantial reality to time over and above the rather sketchy conception of time we have from common sense and from physics. It is the logical analogue of the familiar forms of panpsychism as applied to matter and space.
Temporal panpsychism can come in two strengths, pure and mixed. The pure form maintains that only time has a mental nature—not matter and space. This nature alone suffices to explain the emergence of mind in the universe, and it confers on matter and space whatever substantial being they have. The mixed form is less ambitious claiming only that time has a mental nature in addition to the mental nature of matter and space. This is the natural view to adopt: it simply extends regular matter-space panpsychism to include time, on the principle that it would be odd if the rest of nature were essentially mental but not time. The picture, then, is that matter and space enjoy their own form of mentality while time simply adds more of the same—each has the form of mentality appropriate to its nature. Perhaps time has a more flowing mental nature than matter and space, which are relatively static. The mind of matter and space is a kind of spread-out mind; the mind of time is more of a fluid mind—more like a river than a mountain. We can also distinguish a strong form and a weak form of temporal panpsychism, analogous to parallel doctrines for matter and space: the strong form says that time has an exclusivelymental nature while the weak form holds that time has both a mental nature and a non-mental nature—a kind of double-aspect theory. Pure strong temporal panpsychism thus says that the ultimate reality of the whole world consists in the mental nature of time, and only of time: everything—including matter, space, and animal consciousness—stems from the mental nature of time. This nature might be quite alien to us—we don’t know what it is like to be time—and yet it is the foundation of everything real. Clearly this is an extreme doctrine. Alternatively, the temporal panpsychist might more modestly claim only that the mental reality of time is just one reality among others; it is limited to time itself. Matter and space have their own independent forms of mentality. A psychic trinity prevails in the universe.
It might be wondered how heterogeneous the mental reality of time is. Is time composed of a single phenomenological quality or is it made up of several? Time seems homogenous to us, so the former alternative might seem more natural—time is, as it were, a single-note affair (an eternal C-sharp perhaps). This would pose a problem for its ability to ground the full variety of animal consciousness, but a similar problem arises for material and spatial panpsychism—they too appear more homogeneous than the animal minds they are supposed to explain. So temporal panpsychism is at least no worse off than the more familiar forms of the doctrine. But there is really no logical bar to recognizing greater phenomenological variety: maybe time just seems homogeneous—in its objective being it might be variously hued. Presumably a view of time closer to that of Relativity Theory will render such a conception of time attractive: there are many distinct times (many simultaneities), each relative to a reference frame; and time and motion are more tightly connected than we tend to suppose (plus light seems to have something to do with time). Certainly, if we link time to measuring devices, we will be able to obtain a more variegated view of its nature. If we believe that the ultimate physical reality is something called space-time–a kind of amalgam of time, space, and matter–then we can suppose that time has a richer and more complex structure than under an austerely Newtonian conception. In any case, various metaphysical options are open to us ranging from the monotonously homogeneous to the strikingly heterogeneous.
But is there anything to be said in favor of the doctrine? Yes, in as much as other panpsychist doctrines can claim to have rational support. First, physics tells us little about the nature of time, beyond mathematically describing its structure; the panpsychist can remedy that lacuna by suggesting that time has a hidden mental nature. He can tell us what time intrinsically is—not just specify its abstract form. Russell had the idea that the intrinsic nature of matter is revealed to us in acts of introspection; we could make the same claim about introspection and time. In effect, the brain acts as a window onto the intrinsic nature of time, which is otherwise concealed from us. This nature shows up as our own consciousness of time. Second, consciousness has an essentially temporal character, as has been frequently observed: time and consciousness are closely bound up with each other. This is why some philosophers have been attracted to an account of time as essentially a psychological phenomenon. The temporal dimension of consciousness is as evident as its intentionality and its subjective character (hence time has always been central to the phenomenologists). All conscious experience is consciousness of time; there is no timeless consciousness. Thus we need, in our account of consciousness, an explanation of its temporality—and here temporal panpsychism scores well. The nature of subjective time emerges from the nature of time itself, since objective time already harbors a primitive form of temporal consciousness. The consciousness embedded in time is itself a temporal consciousness, so this is available to provide a foundation for temporal consciousness in sentient beings. The logic here is exactly the same as the logic employed by other proponents of panpsychism—we find the basis of animal minds in the primitive types of mentality generally embedded in the world. Time features in our conscious minds in virtue of temporal mentality in time itself. So temporal panpsychism has the same credentials as material panpsychism. Furthermore, it is difficult to see how it could fail to be entailed by material panpsychism, given that the very existence of physical events and processes requires the participation of time. There is no such thing as matter without time, because material things are subjects of change, so their mental reality must enable them to participate in events and processes—but then it must include time. If matter is ultimately mental, and matter changes, then time must make this possible—and how does it do that without itself having a mental nature? If we think of time as having a mental nature of the type Will, as in Schopenhauer’s philosophy, then this is what is necessary in order to get matter activated—otherwise it is stuck. The mental nature of time is what enables the mental nature of matter to undergo change. Time is the will of matter’s mind. Once we go panpsychist about matter, temporal panpsychism cannot be far behind. The different types of panpsychism thus conspire together to give us the world we experience.
Are there any good objections to panpsychism, temporal or other? Of course there are—plenty of them. I have only suggested that temporal panpsychism needs to be added to the usual kinds in order to round out the metaphysical picture. We need a General Theory of panpsychism, talking in time as well as matter and space. Father Time should be granted his full measure of mentality if other parts of nature are to receive that (possibly dubious) largesse.C
 I am not saying this is not obscure, but then everything is obscure in this area.
 One possible view is that matter embeds only unconscious mental states—pre-conscious qualia—and that it is the mental nature of time that converts this into full conscious awareness. Time acts as a kind of switch turning on the light of consciousness; it does so by adding its own mental nature to the (unconscious) mental nature of matter. The mental nature of time triggers consciousness in the otherwise unconscious mental states already present in matter. For example, matter supplies a subliminal perception of red (possibly in some more primordial form) and then time adds to that the secret sauce of consciousness, thus producing a conscious percept of red. That is, time is specially designed to generate consciousness as such, leaving matter to do the grunt work of producing the raw psychological materials. I have no idea if this hypothesis is true (or even meaningful), but at least it suggests a way of thinking with some theoretical structure. It has the consequence that the whole world is brimming with consciousness as a joint result of the exertions of matter in producing pre-conscious mentality plus the ability of time to inject consciousness into this basic psychological material. There is a kind of division of labor between matter and time in the generation of conscious mentality.
 This paper arose out of an email exchange between Rebecca Goldstein and me, but I blame myself for its existence.