Locke’s thought is quite interesting in this chapter. He is considering René Descartes’ ideas to a certain extent and deliberating on why Descartes’s Meditations were incorrect. Locke doesn’t care fro the idea of extension as a virtual definition of body. Locke also considers the nature of space, and I like that quite a bit for I invented some of the same thoughts myself independently-just a few hundred years later than Locke.
Locke pointed out an argument people make that if space was really nothing there should be nothing between any two objects such that there would be no distance. That idea would apply to distant stars too of course. Locke has many other great ideas yet many of the metaphysical and epistemological sort can be readily recognized as anachronistic in light of quantum theory. I think its possible that epistemology has fully updated the facts that are relevant to the paradigm of Locke in Book two, yet I cannot say what philosophy knows overly well.
Locke makes an interesting comment that Descartes’ idea of body as extension has a logic that requires everything to be one- in unity pervasive. Of course current physical cosmology has a singularity that extends to be the entire Universe and everything in it, so in that sense Descartes was right on the money.
Locke make a great point about relativity however in points 8-10 of chapter thirteen. I think it is better than one might find anywhere else. It brings one to the idea of experience however and the complete phenomenal subjectivity of names and things-in-themselves.
Epistemological objects are part of a unified field- a monism with component attributes that can be regarded by observers as qualitatively so different that they comprise plural objects. Human beings and human minds exist in a unified field. They may make names and categories about experience within that field, yet every idea about what occurs in it is what is permissible by the non-contingent and non-subjective nature of the field. Space for instance is now known not to be empty (it has virtual particles and other elements of the unified field, or Higgs field that may be an emergent quality of some other kind of field.
Humans may say whatever they like about the field elements and its consistent aspects that reproduce in common experience. Even mathematical relations though are subjective and possible only within criteria the field supports. If Riemannian geometry of a select form is an implicit fact of the Universe then whatever mathematics exist that can be consistent must cohere within that mathematical paradigm.
The relations and relativity of body, mass and substance in the field that is the field extended and perceptible for human experience is phenomenal. That is the problem of quantum weirdness about it; it is a steady state with consistent values of a field that includes the observer. It is possible to make practical guidebooks of physics about operations within the field. It does not seem realistic to talk about ‘real objects’ or the reality of things-in-themselves. Humans can interpret the extended field in one way, yet that is probably not the only way it is. Insects may view the Universe in infrared for instance and have an entirely different way of relating to it. If one found space aliens with very different and non-human form they might seem the Universe or field experience in a way dissimilar to that of human experience.