This is a diversion, but I think that you answered my original question well enough. I'm curious about this panexperientialist thing, though. What's the difference between the mental and the physical?
Fundamentally they are not separable, so in some sense they are the same (monism). What one sees depends on how one looks and from where you are observing. We impute mental properties to some substances and not to others. Most think other humans have an interior subjective reality similar to themselves (by analogy not by direct experience or scientific demonstration, reason and analogy, not epistemology.. Many impute an interior subjective life to animals and other highly organized living things. In truth though; the denial of mental properties to any object is an arbitrary decision or dividing line. A lot of problems with respect to mental versus physical (mind-body) tend to go away when one begins to consider that reality is dipolar, that substances are really enduring events, and that all events have both a mental and a physical aspect or manifestation.
You say that reality is composed of events not particles, but aren't events composed by particles?
Everyone perceives that there are events as well as substances. The general assumption is that events are secondary to substances. Events are subordinated metaphysically to substances. The dominant notion is of substances (atoms,matter) with enduring attributes in relative motion. When one investigates the concept of enduring substances or matter paradoxes begin to occur especially at the quantum level. The fundamental constituents of matter do not behave like substances are supposed to behave. In fact matter at the quantum level behaves more like quantum events than particles or substances. Despite this the assumption that ultimate reality consists of particles (which lack any mental properties of degrees of freedom) continues to dominate most of our thinking.
Process philosophy takes a look at the opposite option that events are primary and substances are secondary. In process thinking events in relation dominate over substances in relative motion. Substances are now thought of as stable patterns of events. In many ways process thinking fits the discoveries of modern physics better than the traditional notion of matter, atoms and indivisible or fundamental particles.
What do you mean when you say events?
For process philosophers (A.N.Whitehead is the most prominent example) reality consists of "occasions, moments or droplets of experience" one rapidly following another. The typical phrase is "perpetual perishing and rebirth" . Reality consists of "one moment of experience perishes and a new moment of experience is born which incorporates elements of the past and chooses from among the possibilities of the future". Material objects are not stable substances with enduring attributes. We in fact know that objects are mostly empty space, constantly in motion and constantly changing. Substances are in fact enduring sequences of events.
What do you mean when you say that mental properties are not consciousness?
Panexperientialists deliberately avoid using terms like "consciousness or mind" because of the implications about human like self awareness or self reflection which accompany those terms. The language instead focuses on less concept laden terms like perception (awareness), memory, or self determination, interiority, etc. Even fundamental particles appear to be aware of their surroundings, have memory and exhibit degrees of freedom in response ( see for instance quantum entanglement, pairing, etc). For a Panpsychist mind and consciousness are found in highly organized societies but the fundamental mental properties which combine to form minds and consciousness are present at the very core of reality.
Individual properties of the brain may not be conscious, but together they form the functional basis for consciousness.
What are the fundamental properties which combine to create consciousness?
Perception (awareness of surroundings), memory (elements of the past),etc ?
What actual entities posses these fundamental mental properties?
Do animals engage in purposeful activity? Do plants? How do you know?
Do you really have access to the interior subjection component of any other entities experience? How do you know? Is the sudden emergence of the fundamental properties of mind compatible with the evolutionary process in cosmology or biology? Is not the slow emergence of what we call mind and consciousness from more elemental mental properties the more likely explanation? The decision to draw the line at any point is somewhat arbitrary.
Descartes separated reality into mind and matter (res extensa). Science proceeded to be extremely productive in its considerations of the material aspects of reality but intractable problems have developed with respect to mental phenomena. All purely materialist philosophies divide the world into mental and physical they are forms of dualism. The perceived truth is that of unity(monism), that things only exists in relation to other things and that things really are "events" not substances.
What do you mean when you say that rocks may have primitive mental properties? Can you describe these mental properties that a rock may have?
Again to be clear, rocks as aggregates do not have consciousness, mind, thoughts or any other higher mental attributes. The individual constituents of rocks i.e. the fundamental particles of which a rock is composed may have properties which could be considered to be primitive mental properties.
In a nutshell this is a poor presentation of process philosophy and panexperientialism. It takes a little practice but entertaining these notions can have a profound effect upon your thinking and how you view the universe. I find it much more inspiring than any form of materialism (especially any mechanistic or deterministic notion). It also makes the dualism of mind-body, matter-mental appear much less intractable.
This is speculative philosophy based on reason and analogy which is not in conflict with science or experience. It is a different view than the mechanistic one that developed following Newtonian physics and which still dominates modern thinking.
Lines of thought similar if not identical to panexperientialism are panpsychism and psychialism. There are lots of serious presentations of process philosophy. Whitehead himself is difficult to read because he invented new terminology to avoid using older terms which carried unwanted implications and associations.