Long overdue:

In May when I composed this post, I saw the LW community as having a dominant ideology, which I have since learned to label 'physical materialism'. I refrained from publically defining this ideology because of some kind of reluctance.

I didn't expect the community to change over time, but it seems to me there has been drift in the type of discussions that occur on Less Wrong away from epistemological foundations. So I feel more comfortable now outlining the tenets of average LW epistemology, as I perceived it, as a ‘historical’ observation.

The first and fundamental tenet of this epistemology is that there is a real, objective reality X that we observe and interact with. In contrast, persons with a metaphysical bent are less definitive about the permanent existence of an objective reality, and believe that reality alters depending on your thoughts and interactions with it. On the other extreme are skeptics that believe it is meaningless to consider any objective reality, because we cannot consider it objectively. (There are only models of reality, etc.)

For formalism and precision, I will here introduce some definitions. Define objective reality as a universe X = the set of everything that we could ever potentially observe or interact with physically. (This is what we consider “real”.) We cannot know if X is a subset of a larger universe X-prime. Suppose that it is: The component of X-prime that is outside X (X-complement) may ‘exist’ in some sense but is not real to us.

The second tenet is that anything we observe or interact with is a subset of X, the real physical world. While this trivially follows from the definition of X, what is being argued with physical materialism is not the tautology itself but the value of seeing things from this point of view. Trivially, there is nothing metaphysical in X; we either interact with something or we don’t.

In contrast, the metaphysical view is to consider reality = X-prime, and consider that everything we interact with physically/scientifically/objectively may only be a subset of our total experience of reality.

Comparing the views: Physical Materialism verses Metaphysical View

Consider the hypothetical, real sighting of a ghost: a white floating image is observed in front of two observers. The physical materialist observes the ghost, and knows that either (a) the ghost exists outside subjective experience, in which case the ghost must be reflecting light in such a way as to appear white and hazy, and the interaction of the light with the ghost could be studied and reproduced or (b) the ghosts exists as a subjective experience, in which case it is still physically manifested as a hallucination that may be equal to certain neural patterns, etc. The metaphysicist, in contrast, considers a third possibility as potentially reasonable: the ghost has a physical component (same cases a,b) AND ALSO a metaphysical component that explains the ‘existence’ of the ghost in some deeper way. For the metaphysicist, the physical materialist’s ghost is a subset of the “whole” ghost that actually straddles X and X- complement.

In my view, the physical materialist view is more coherent. We cannot know if the ghost straddles X and X-complement, but if it does, in no sense is the part of the ghost contained within X- complement “real” to us. It is not real because we can never observe or interact with this component in any way.

The epistemological question, all along; the debate over the ages, is whether holding any X- complement component (imaginary component) in our theory of the ghost will give us a better understanding of the X component (real part) of the ghost.

Personally, I see no evidence that the physical world X should not be informationally/theoretically complete. The labor of science is the belief that X can be understood within X itself. On the other hand, there is no proof that X is not dependent upon or manipulated in (scientifically) unfathomable ways by a larger X-prime, and it is conceivable that interactions occur between X and X-complement in ways that cannot be understood within X. Physical materialism really is just a matter of ideological preference, not fact. But it is the direction modern culture is certainly going; metaphysical religious views seem increasingly anachronistic and ‘separate’.

Another point of view typically held on Less Wrong: that since reality is 'just' physical that this implies that it is coarse, or simple or stupid. I think this is just a backlash to metaphysical accounts describing reality as divine and inspired. We can look around and see that reality is structured, patterned and organized/directed*. Physical materialism is not the belief that these observations are nonsense, but that we can explain them without resorting to the supernatural.

*Please allow materialistic interpretations of these anthropomorphic words… I'm not aware of adequate alternatives and suspect language is evolving too slowly.