Please elaborate on this
I suppose your question is on how it is possible for particles to have experiential qualities?
Firstly, there are a number of things meant by experience and it has many different aspects - for this explanation I am only focusing on one aspect of the problem. The many aspects include the causal efficacy of the mental, the boundary problem of experience, the qualia problem and so on. I will only be discussing the qualia problem here - in short it is the problem of why it is that our experience has a qualitative nature that is unexplained in its physical properties, so for instance, why is it that red appears as it does even though taking the purely physical definition of red (the wavelength of an electromagnetic wave) offers no suggestion of what the colour feels
The thesis of panpsychism is that the elementary particles that constitute reality have within them experiential qualities to explain this problem of qualia as now we can see how experience exists in the world independent of the purely physical descriptions of objects. This thesis follows from a number of premises and assumptions and I think these assumptions are reasonable to make. So, to begin:
1. Experience exists.
This is a premise of the argument and in my opinion the only thing that we can know with certainty - it is beyond doubt.
2. Experience is a natural aspect of the real world.
This is an assumption that requires one to accept the established pre-conditions of what it means to "exist" in the real world - ie, that whatever it is that exists conforms to the laws of physics (whatever the truth of them may be) and is embedded in a four dimensional space-time matrix. To reject this premise is to either state that our experience is outside of physical reality and thus a miracle every time we have an experience, or to bluntly reject the existence of experience itself. I think it is a reasonable assumption to accept that experience is a part of physical reality and that it is neither a miracle nor an illusion - it is as natural as any other physical phenomena.
3. All natural phenomena are constituted by elementary particles.
This is a rather less firm assumption than the previous one but it is the paradigm of all contemporary physics and philosophical thinking. Perhaps it is the case that this dicing of reality into logical, atomical pieces is just an illusory exercise and that reality itself is one whole without individual parts. Regardless, I do not think it is important at this stage to argue this point either way and because much of current thought is couched in terms of elementary particles I am happy to go along with it for now as a reasonable assumption.
4. Weak monism is true.
This is the assumption that there is one kind of stuff in the universe, as opposed to the stronger monistic view that the universe is just one thing. I think weak monism is a reasonable assumption.
Now, having taken these premises, the case for panpsychism is as follows:
5. Experience, as I have it, is a real physical property of my body and thus requires explanation in terms of the physical.
6. From 3, this explanation will take the form of establishing the character of the elementary particles of reality and from there extrapolating to the case of human experience.
7. The character of the elementary particles, thus, must have within them an explanation of experience. This is the crucial point in this argument. There have been alternatives explored and many of them centre on the idea of emergence.
Briefly, the idea is that while elementary particles may not have any experiential qualities themselves, they do however have within them the foundations upon which experience then later emerges.
The classic example, which I attempted to show above, is that of wetness. The example states that while individual molecules of water have no property of wetness, the moment they are brought together at the right temperature (ie speed of motion) the collection of molecules has the property of being wet. The analogy supposedly proves that it is possible to bring together elementary particles such that a new property emerges that is not apparent before the arrangement.
However, I think this approach is insufficient to account for experience in the same way. Wetness is clearly defined within physics as the motion of molecules within a loose structure at a certain speed and ability to slide free of the other particles. The idea of motion and the idea of structure, even motion that is loose and able to slide free of a structure are all inherent in the idea of the molecule itself. In other words, there is no new matter of fact when one takes molecules together and notices that they display a different motion and structure to before because the laws of motion are already so constrained so as to allow for such motion. The other point is that this definition of molecular motion takes place in exactly the same lexicon as before - we are still discussing charge/mass/spin whether or not we are referring to a water molecule in isolation or to a water molecule in a "wet" structure.
The case of experience I think is different. Firstly, we do not have a defining concept on what it means to experience like we do for wetness, it cannot be quantitatively measured nor can it be logically delineated - all we know is that we have it, perhaps the having is the knowing but I will leave this part out for now. The point is that while wetness can be seen to be defined with the same parameters that elementary particles are defined by, it is difficult to see how exactly experience can be defined in terms of mass/charge/spin etc.
8. If we thus reject emergentism, we either suggest that experience somehow has become part of the universe without explanation or that experience was always a part of the universe. The former view is very conservative but some philosophers have suggested it and refused to tackle the problem anymore. I think, however, that the latter view is a more reasonable position. The view is such that it is fair to say that experience is just the firing of neurons, however, the nature of these neurons cannot then be constrained to the same parameters as above – they must have some additional property that has within it the seed of experience, or experience itself, as inherent and not as a brute fact.
9. Therefore, once it is accepted that experience exists; that experience is as real as any other physical phenomena; that all phenomena is made of the same elementary particles; that phenomena must be explainable in a non-arbitrary way through the properties of those elementary particles, then it follows that those elementary particles must have some sort of experiential quality that can combines to form the experience we have.
10. Hence, panpsychism.
There are some provisos to this thesis of course.
It is impossible to say exactly what the nature of the experience of elementary particles is – all we can say is that there is in some sense an experiential quality. I do not think, using the argument above, that there is any way that we can reasonably deduce the character of this experience but perhaps it is possible to know this through a different argument. This argument cannot encompass that aspect.
Panpsychism itself faces problems when it begins to speculate on the nature of this experience for particles. The biggest problem is the “combination” problem which simply put is the difficulty of developing a metaphysical system in which one can combine experiences to form one larger experience. Seeing as we have defined experience above as being qualitative, it is difficult to see how we can quantify it when we want to combine the experience of particles to form the experience of a person for instance. However, I do not think this problem detracts from the argument above – what it detracts from is sub-par speculation on the next move, the move to discover the nature of the experience of these particles.
Finally, this is a metaphysical thesis and thus it will have assumptions – every metaphysical thesis does. The mind-body problem, whichever way it is solved, will definitely require reasonable assumptions to be made and I think I have made reasonable assumptions above. In my opinion, the argument is valid, whether or not one accepts the assumptions that I have made. There are other arguments that can be used to reach the conclusion of panpsychism and I think they can hold as much validity as this one.