Byrnema, you talk extensively in this post about the LW community having a (dominant) ideology, without ever really explicitly stating what you think this ideology consists of.
I’d be interested to know what, from your perspective are the key aspects of this ideology. I think this would have two benefits:
the assumptions underlying our own ideologies aren’t always clear to us, and having them pointed out could be a useful learning experience; and
the assumptions underlying others’ ideology aren’t always clear to us, and making your impressions explicit would allow others the chance to clarify if necessary, and make sure we’re all on the same page.
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.
I feel at home with physical materialism and I like the way it’s simultaneously simple, self-consistent and powerful as a theory for generating explanation (immediately: all of science). Yet there are some interesting issues that come up when I think about the justification of this world view.
The more complex hypothesis that there is ‘more’ than X would be favored by any evidence whatsoever that X is not completely self-contained. So then it becomes an argument about what counts as evidence, and “real” experience. The catch-22 is that any evidence that would argue for the metaphysical would either be rejected within X as NOT REAL or, if it was actually real—in other words, observable, reproducible, explainable—then it would just be incorporated as part of X. So it is impossible to refute the completeness of X from within X. (For example, even while QM observations are challenging causality, locality, counterfactual definiteness, etc., physicists are looking to understand X better, and modify X as needed, not rejecting the possibility of a coherent theory of X. But at what point are we going to recover the world that the metaphysicists meant all along? )
So the irrefutability of physical materialism is alarming, and the obstinate stance for ‘something else’ from the majority of my species leaves me interested in the question. I have nothing to lose from a refutation of either hypotheses, I’m just curious. Also despairing to some extent—I believe such a questions are actually outside definitive epistemology.
This is completely backwards. It’s non-materialism that irrefutable, pretty much by definition.
Suppose we allow non-materialistic, non-evidence-based theories. There is an infinite number of theories that describe X plus some non-evidential Y, for all different imaginable Ys. By construction, we can never tell which of these theories is more likely to be wrong then another.
So we can never say anything about the other-than-X stuff that may be out there. Not “a benevolent god”. Not “Y is pretty big”. Not “Y exists”. Not “I feel transcendental and mystical and believe in a future life of the soul”. Not “if counterfactually the universe was that way instead of this way, we would observe Y and then we would see a teacup.” Nothing at all can be said about Y because every X+Y theory that can be stated is equally valid, forever.
Whatever description you give of Y, with your completely untestable religious-mental-psychic-magical-quantum powers of the mind that must not be questioned, I can give the precise opposite description. What reason could you have for preferring your description to mine? If your reason is in X, it can’t give us information about Y. And if your reason is in Y, I can claim an opposite-reason for my opposite-theory which is also in Y, and we’ll degenerate to a competition of divinely inspired religions that must not be questioned.
Bottom line: if the majority of the species believes in “something else”, that is a fact about the majority of the species, not about what’s out there. If I develop the technology for making almost all humans stop believing in “something else”, could that possibly satisfy your private wonderings?
This is completely backwards. It’s non-materialism that irrefutable, pretty much by definition.
Non-materialism is irrefutable within its own framework, agreed. So then we are left with two irrefutable theories, but one is epistemologically useful within X and one is not. Materialism wins.
Nevertheless, just to echo your argument across the canyon: reality doesn’t care what theories we “allow”, it is what it is. We might deduce that such-and-such-theory is the best theory for various epistemological reasons, but that wouldn’t make the nature of the universe accessible if it isn’t in the first place. Just reminding that ascetic materialism doesn’t allow conviction about materialism.
reality doesn’t care what theories we “allow”, it is what it is.
It is what X is. That’s the definition of X. Whatever is outside X is outside Reality. Materialists don’t think that “something outside reality” is a meaningful description, but that is what you claim when you talk about things being beyond X.
We might deduce that such-and-such-theory is the best theory for various epistemological reasons
No. We deduce that it’s the best theory because it’s only uniquely identifiable theory, as I said before.
If you’re going to pick any one theory, the only theory you can pick is a materialistic one. If you allow non materialistic theories, you have to have every possible theory all at once.
Well, dunno. To be fair, for the sake of argument, I guess one could maybe propose Idealistic theories. That is, that all that exists is made up of a “basic physics of consciousness”, and everything else that we is just an emergent phenomenon of that. One would still keep reductionism, simply that one might have the ultimate reduction be to some sort of “elementry qualia” plus simple rules (as strict and precise and simple as any basic physics theory) for how those behave.
(Note, I’m not advocating this position at this time, I’m just saying that potentially one could have a non materialist reductionism. If I ever actually saw a reduction like that that could successfully really predict/model/explain stuff we observe, I’d be kinda shocked and impressed.)
For the sake of argument, thank you. Yet I would guess that the theory you propose is still isomorphic to physical materialism, because physical materialism doesn’t say anything about the nature of the elementary material of the universe. Calling it an elementary particle or calling it elementary qualia is just a difference in syllables, since we have no restrictions on what either might be like.
Yet you remind me that we can arrive at other unique theories, within different epistemological frameworks. What I thought you were going to say is that a metaphysicist might propose a universe X-prime that is the idealization of X. As in, if we consider X to be an incomplete, imperfect structure, X-prime is the completion of X that makes it ideal and perfect. Then people can speculate about what is ideal and perfect, and we get all the different religions. But it is unique in theory.
By the way, the epistemology used there would seem backwards to us. While we use logic to deduce the nature of the universe from what we observe, in this theory, what they observe is measured against what they predict should logically be. That is, IF they believe that “ideal and perfect” logically follows. (This ‘epistemology’ clearly fails in X, which is why I personally would reject it, but of course, based on a theory that ordinates X above all, even logic.)
Suppose you believe a theory such as you described. Then I propose a new theory, with different elementary qualia that have different properties and behaviors, but otherwise obey the meta-rules of your theory—like proposing a different value for physical constants, or a new particle.
If the two theories can be distinguished in any kind of test, if we can follow any conceivable process to decide which theory to believe, then this is materialism, just done with needlessly complicated theories. On the other hand, if we can’t distinguish these theories, then you have to believe an infinite number of different theories equally, as I said.
I’m perfectly happy with the idea that there could be stuff that we can’t know about simply because it’s too “distant” in some sense for us to experience it; it sends no signals or information our way. I’m not sure anyone here would deny this possibility.
But if that stuff interacts with our stuff then we certainly can know about it.
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.
If a particular ontological commitment gives us a better understanding of something than it is no longer in the X-complement. We are officially observing/ interacting with it. Neptune for example, before it was observed by telescope, was merely a theoretical entity needed for explaining perturbations in the orbit of Uranus. There was a mysterious feature of the solar system and we explained it by positing an astronomical entity. There was nothing unscientific about this.
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.
See, if there are interactions between X and X-Complement then there are interactions between us and X-Complement. X and X-Complement, by definition cannot be causally related. The question then is if physical entities and physical causes are sufficient for accounting for all our experiences. If they weren’t we would have a reason to favor a Spiritual or X-Skeptical view. But, in fact, we’ve been really good about explaining and predicting experiences using just physical and scientific-theoretical entities.
To conclude: I see three distinctions where you see two. There is the Scientific- physicalism of Less Wrong, the Spiritual view which holds that there are things that are not physical and that we can (only or chiefly) observe and interact with those things through means other than science, and finally, the Extreme Skeptic view which considers all our experiences as being structured by our brain or mind then as the effects of entities that are not part of our mind/brain. Moreover, the possibility you see, of our inability to make sense of physical universe we have access to because of interactions between that universe and one we do not have access to, does not exist. This is because the boundaries of what we have access to are the universe’s boundaries of interaction. Anything that influences the reality we have access to we can include in our model of reality. And it turns out that a scientific-physicalist view is more or less successful and explaining and predicting experiences.
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.
If a particular ontological commitment gives us a better understanding of something than it is no longer in the X-complement. We are officially observing/ interacting with it. Neptune for example, before it was observed by telescope, was merely a theoretical entity needed for explaining perturbations in the orbit of Uranus. There was a mysterious feature of the solar system and we explained it by positing an astronomical entity. There was nothing unscientific about this.
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.
See, if there are interactions between X and X-Complement then there are interactions between us and X-Complement. X and X-Complement, by definition cannot be causally related. The question then is if physical entities and physical causes are sufficient for accounting for all our experiences. If they weren’t we would have a reason to favor a Spiritual or X-Skeptical view. But, in fact, we’ve been really good about explaining and predicting experiences using just physical and scientific-theoretical entities.
To conclude: I see three distinctions where you see two. There is the Scientific- physicalism of Less Wrong, the Spiritual view which holds that there are things that are not physical and that we can (only or chiefly) observe and interact with those things through means other than science, and finally, the Extreme Skeptic view which considers all our experiences as being structured by our brain or mind then as the effects of entities that are not part of our mind/brain. Moreover, the possibility you see, of our inability to make sense of physical universe we have access to because of interactions between that universe and one we do not have access to, does not exist. This is because the boundaries of what we have access to are the universe’s boundaries of interaction. Anything that influences the reality we have access to we can include in our model of reality. And it turns out that a scientific-physicalist view is more or less successful and explaining and predicting experiences.
Byrnema, you talk extensively in this post about the LW community having a (dominant) ideology, without ever really explicitly stating what you think this ideology consists of.
I’d be interested to know what, from your perspective are the key aspects of this ideology. I think this would have two benefits:
the assumptions underlying our own ideologies aren’t always clear to us, and having them pointed out could be a useful learning experience; and
the assumptions underlying others’ ideology aren’t always clear to us, and making your impressions explicit would allow others the chance to clarify if necessary, and make sure we’re all on the same page.
(More generally, I think this is a great idea.)
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.
But is there any reason to favour this more complex hypothesis?
I feel at home with physical materialism and I like the way it’s simultaneously simple, self-consistent and powerful as a theory for generating explanation (immediately: all of science). Yet there are some interesting issues that come up when I think about the justification of this world view.
The more complex hypothesis that there is ‘more’ than X would be favored by any evidence whatsoever that X is not completely self-contained. So then it becomes an argument about what counts as evidence, and “real” experience. The catch-22 is that any evidence that would argue for the metaphysical would either be rejected within X as NOT REAL or, if it was actually real—in other words, observable, reproducible, explainable—then it would just be incorporated as part of X. So it is impossible to refute the completeness of X from within X. (For example, even while QM observations are challenging causality, locality, counterfactual definiteness, etc., physicists are looking to understand X better, and modify X as needed, not rejecting the possibility of a coherent theory of X. But at what point are we going to recover the world that the metaphysicists meant all along? )
So the irrefutability of physical materialism is alarming, and the obstinate stance for ‘something else’ from the majority of my species leaves me interested in the question. I have nothing to lose from a refutation of either hypotheses, I’m just curious. Also despairing to some extent—I believe such a questions are actually outside definitive epistemology.
This is completely backwards. It’s non-materialism that irrefutable, pretty much by definition.
Suppose we allow non-materialistic, non-evidence-based theories. There is an infinite number of theories that describe X plus some non-evidential Y, for all different imaginable Ys. By construction, we can never tell which of these theories is more likely to be wrong then another.
So we can never say anything about the other-than-X stuff that may be out there. Not “a benevolent god”. Not “Y is pretty big”. Not “Y exists”. Not “I feel transcendental and mystical and believe in a future life of the soul”. Not “if counterfactually the universe was that way instead of this way, we would observe Y and then we would see a teacup.” Nothing at all can be said about Y because every X+Y theory that can be stated is equally valid, forever.
Whatever description you give of Y, with your completely untestable religious-mental-psychic-magical-quantum powers of the mind that must not be questioned, I can give the precise opposite description. What reason could you have for preferring your description to mine? If your reason is in X, it can’t give us information about Y. And if your reason is in Y, I can claim an opposite-reason for my opposite-theory which is also in Y, and we’ll degenerate to a competition of divinely inspired religions that must not be questioned.
Bottom line: if the majority of the species believes in “something else”, that is a fact about the majority of the species, not about what’s out there. If I develop the technology for making almost all humans stop believing in “something else”, could that possibly satisfy your private wonderings?
Non-materialism is irrefutable within its own framework, agreed. So then we are left with two irrefutable theories, but one is epistemologically useful within X and one is not. Materialism wins.
Nevertheless, just to echo your argument across the canyon: reality doesn’t care what theories we “allow”, it is what it is. We might deduce that such-and-such-theory is the best theory for various epistemological reasons, but that wouldn’t make the nature of the universe accessible if it isn’t in the first place. Just reminding that ascetic materialism doesn’t allow conviction about materialism.
It is what X is. That’s the definition of X. Whatever is outside X is outside Reality. Materialists don’t think that “something outside reality” is a meaningful description, but that is what you claim when you talk about things being beyond X.
No. We deduce that it’s the best theory because it’s only uniquely identifiable theory, as I said before.
If you’re going to pick any one theory, the only theory you can pick is a materialistic one. If you allow non materialistic theories, you have to have every possible theory all at once.
Well, dunno. To be fair, for the sake of argument, I guess one could maybe propose Idealistic theories. That is, that all that exists is made up of a “basic physics of consciousness”, and everything else that we is just an emergent phenomenon of that. One would still keep reductionism, simply that one might have the ultimate reduction be to some sort of “elementry qualia” plus simple rules (as strict and precise and simple as any basic physics theory) for how those behave.
(Note, I’m not advocating this position at this time, I’m just saying that potentially one could have a non materialist reductionism. If I ever actually saw a reduction like that that could successfully really predict/model/explain stuff we observe, I’d be kinda shocked and impressed.)
For the sake of argument, thank you. Yet I would guess that the theory you propose is still isomorphic to physical materialism, because physical materialism doesn’t say anything about the nature of the elementary material of the universe. Calling it an elementary particle or calling it elementary qualia is just a difference in syllables, since we have no restrictions on what either might be like.
Yet you remind me that we can arrive at other unique theories, within different epistemological frameworks. What I thought you were going to say is that a metaphysicist might propose a universe X-prime that is the idealization of X. As in, if we consider X to be an incomplete, imperfect structure, X-prime is the completion of X that makes it ideal and perfect. Then people can speculate about what is ideal and perfect, and we get all the different religions. But it is unique in theory.
By the way, the epistemology used there would seem backwards to us. While we use logic to deduce the nature of the universe from what we observe, in this theory, what they observe is measured against what they predict should logically be. That is, IF they believe that “ideal and perfect” logically follows. (This ‘epistemology’ clearly fails in X, which is why I personally would reject it, but of course, based on a theory that ordinates X above all, even logic.)
I don’t see how that contradicts what I said.
Suppose you believe a theory such as you described. Then I propose a new theory, with different elementary qualia that have different properties and behaviors, but otherwise obey the meta-rules of your theory—like proposing a different value for physical constants, or a new particle.
If the two theories can be distinguished in any kind of test, if we can follow any conceivable process to decide which theory to believe, then this is materialism, just done with needlessly complicated theories. On the other hand, if we can’t distinguish these theories, then you have to believe an infinite number of different theories equally, as I said.
I’m perfectly happy with the idea that there could be stuff that we can’t know about simply because it’s too “distant” in some sense for us to experience it; it sends no signals or information our way. I’m not sure anyone here would deny this possibility.
But if that stuff interacts with our stuff then we certainly can know about it.
Continued...
Now (finally) to the comparison.
If a particular ontological commitment gives us a better understanding of something than it is no longer in the X-complement. We are officially observing/ interacting with it. Neptune for example, before it was observed by telescope, was merely a theoretical entity needed for explaining perturbations in the orbit of Uranus. There was a mysterious feature of the solar system and we explained it by positing an astronomical entity. There was nothing unscientific about this.
See, if there are interactions between X and X-Complement then there are interactions between us and X-Complement. X and X-Complement, by definition cannot be causally related. The question then is if physical entities and physical causes are sufficient for accounting for all our experiences. If they weren’t we would have a reason to favor a Spiritual or X-Skeptical view. But, in fact, we’ve been really good about explaining and predicting experiences using just physical and scientific-theoretical entities.
To conclude: I see three distinctions where you see two. There is the Scientific- physicalism of Less Wrong, the Spiritual view which holds that there are things that are not physical and that we can (only or chiefly) observe and interact with those things through means other than science, and finally, the Extreme Skeptic view which considers all our experiences as being structured by our brain or mind then as the effects of entities that are not part of our mind/brain. Moreover, the possibility you see, of our inability to make sense of physical universe we have access to because of interactions between that universe and one we do not have access to, does not exist. This is because the boundaries of what we have access to are the universe’s boundaries of interaction. Anything that influences the reality we have access to we can include in our model of reality. And it turns out that a scientific-physicalist view is more or less successful and explaining and predicting experiences.
Edit: My comment was way too long, but not sure if this justifies a full post.
Now (finally) to the comparison.
If a particular ontological commitment gives us a better understanding of something than it is no longer in the X-complement. We are officially observing/ interacting with it. Neptune for example, before it was observed by telescope, was merely a theoretical entity needed for explaining perturbations in the orbit of Uranus. There was a mysterious feature of the solar system and we explained it by positing an astronomical entity. There was nothing unscientific about this.
See, if there are interactions between X and X-Complement then there are interactions between us and X-Complement. X and X-Complement, by definition cannot be causally related. The question then is if physical entities and physical causes are sufficient for accounting for all our experiences. If they weren’t we would have a reason to favor a Spiritual or X-Skeptical view. But, in fact, we’ve been really good about explaining and predicting experiences using just physical and scientific-theoretical entities.
To conclude: I see three distinctions where you see two. There is the Scientific- physicalism of Less Wrong, the Spiritual view which holds that there are things that are not physical and that we can (only or chiefly) observe and interact with those things through means other than science, and finally, the Extreme Skeptic view which considers all our experiences as being structured by our brain or mind then as the effects of entities that are not part of our mind/brain. Moreover, the possibility you see, of our inability to make sense of physical universe we have access to because of interactions between that universe and one we do not have access to, does not exist. This is because the boundaries of what we have access to are the universe’s boundaries of interaction. Anything that influences the reality we have access to we can include in our model of reality. And it turns out that a scientific-physicalist view is more or less successful and explaining and predicting experiences.