Whereof one cannot speak, thereof one must be silent.
Ludwig Wittgenstein, Tractatus Logico-Philosophicus*
Some criticism of my post on physicalism is that it discusses reference, not the world. To quote one comment: "I consider references to be about agents, not about the world." To quote another: "Remember, you have only established that indexicality is needed for reference, ie. semantic, not that it applies to entities in themselves" and also "you need to show that standpoints are ontologically fundamental, not just epistemically or semantically." A post containing answers says: "However, everyone already kind of knows the we can't definitely show the existence of any objective reality behind our observations and that we can only posit it." (Note, I don't mean to pick on these commentators, they're expressing a very common idea)
These criticisms could be rephrased in this way:
"You have shown limits on what can be referenced. However, that in no way shows limits on the world itself. After all, there may be parts of the world that cannot be referenced."
This sounds compelling at first: wouldn't it be strange to think that properties of the world can be deduced from properties of human reference?
But, a slight amount of further reflection betrays the absurdity involved in asserting the possible existence of un-referenceable entities. "Un-referenceable entities" is, after all, a reference.
A statement such as "there exist things that cannot be referenced" is comically absurd, in that it refers to things in the course of denying their referenceability.
We may say, then, that it is not the case that there exist things that cannot be referenced. The assumption that this is the case leads to contradiction.
I believe this sort of absurdity is quite related to Kantian philosophy. Kant distinguished phenomena (appearances) from noumena (things-in-themselves), and asserted that through observation and understanding we can only understand phenomena, not noumena. Quoting Kant:
Appearances, to the extent that as objects they are thought in accordance with the unity of the categories, are called phaenomena. If, however, I suppose there to be things that are merely objects of the understanding and that, nevertheless, can be given to an intuition, although not to sensible intuition, then such things would be called noumena.
Critique of Pure Reason, Chapter III
Kant at least grants that noumena are given to some "intuition", though not a sensible intuition. This is rather less ridiculous than asserting un-referenceability.
It is ironic that noumena-like entity being hypothesized in the present case (the physical world) would, by Kant's criterion, be considered a scientific entity, a phenomenon.
Part of the absurdity in saying that the physical world may be un-referenceable is that it is at odds with the claim that physics is known through observation and experimentation. After all, un-referenceable observations and experimental results are of no use in science; they couldn't made their way into theories. So the shadow of the world that can be known (and known about) by science is limited to the referenceable. The un-referenceable may, at best, be inferred (although, of course, this statement is absurd in refererring to the un-referenceable).
It's easy to make fun of this idea of un-referenceable entities (infinitely more ghostly than ghosts), but it's worth examining what is compelling about this (absurd) position, to see what, if anything, can be salvaged.
From a modern perspective, we can see things that a pre-modern perspective cannot conceptualize. For example, we know about gravitational lensing, quantum entanglement, Cesium, and so on. It seems that, from our perspective, these things-in-themselves did not appear in the pre-modern phenomenal world. While they had influence, they did not appear in a way clear enough for a concept to be developed.
We may believe it is, then, normative for the pre-moderns to accept, in humility, that there are things-in-themselves they lack the capacity to conceptualize. And we may, likewise, admit this of the modern perspective, in light of the likelihood of future scientific advances.
However, conceptualizability is not the same as referenceability. Things can be pointed to that don't yet have clear concepts associated with them, such as the elusive phenomena seen in dreams.
In this case, pre-moderns may point to modern phenomena as "those things that will be phenomena in 500 years". We can talk about those things our best theories don't conceptualize that will be conceptualized later. And this is a kind of reference; it travels through space-time to access phenomena not immediately present.
This reference is vague, in that it doesn't clearly define what things are modern phenomena, and also doesn't allow one to know ahead of time what these phenomena are. But it's finitely vague, in contrast to the infinite vagueness of "un-referenceable entities". It's at least possible to imagine accessing them, by e.g. becoming immortal and living until modern times.
A case that our current condition (e.g. modernity) cannot know about something can be translated into a reference: a reference to that which we cannot know on account of our conditions but could know under other imaginable conditions. Which is, indeed, unsurprising, given that any account of something outside our understanding existing, must refer to that thing outside our understanding.
My critique of an un-refererenceable objective physical world is quite similar to Nietzsche's of Kant's unknowable noumena. Nietzsche wrote:
The "thing-in-itself" nonsensical. If I remove all the relationships, all the "properties," all the "activities" of a thing, the thing does not remain over; because thingness has only been invented by us owing to the requirements of logic, thus with the aim of defining, communication (to bind together the multiplicity of relationships, properties, activities).
Will to Power, sec. 558
I continue to be struck by the irony of the transition from physical phenomena to physical noumena. Kant's positing of a realm of noumena was, perhaps, motivated by a kind of humility, a kind of respect for morality, an appeasement of theological elements in society, while still making a place for thinking-for-one's-self, science, and so on, in a separate magisterium that can't collide with the noumenal realm.
Any idea, whether it's God, Physics, or Objectivity, can disconnect from the human cognitive faculty that relates ideas to the world of experience, and remain as a mere signifier, which persists as a form of unfalsifiable control. When Physics and Objectivity take on theological significance (as they do in modern times), a move analogous to Kant's will place them in an un-falsifiable noumenal realm, with the phenomenal realm being the subjective and/or intersubjective. This is extraordinarily ironic.