Does a sentence only mean something because it draws on knowledge outside of itself? Take 2 + 2 = 4: is it a tautology? No: it depends on a conception of '+', which is not located within that sentence/equation. Some claim that no matter what your sentence/claim, it always relies on something beyond, a 'background' which cannot be articulated. (An attempt at articulating just pushes things back one level of regress.)
I've come across this idea in several places and it seems very important, if correct. For example, in Mortimer Adler's Ten Philosophical Mistakes, he argues that the first mistake (chapter: "Consciousness and Its Objects") is to think that we are conscious of everything in our thoughts, instead of only being conscious of the object of thought, and not the "thinking about the object". There is no "view from nowhere": the thought-stuff we use to think about can never be directly accessed unless it itself becomes an object of some other thought-stuff.
It would appear that two people cannot even communicate well unless their unarticulated backgrounds are sufficiently similar for the topic under discussion. There do seem to be ways to isolate the 'microstructure' of the unarticulated background from the ideas being discussed, like phase transitions in matter can be somewhat agnostic to the microstructure of the constituent particles (see Pigliucci's Essays on Emergence, part I). However, when this isn't done, it would appear that the way two people get their unarticulated backgrounds to 'sufficiently agree' is a somewhat mysterious process. I would like to understand this process more.
Possible examples
1. Michael Polanyi calls this "tacit knowledge" in his 1958 Personal Knowledge and 1966 The Tacit Dimension. Most briefly, as Polanyi says in Tacit (more):
we can know more than we can tell (4)
An easy example is that there is a huge difference between telling someone how to run an experiment and showing that person how to do so. While more is communicated in the latter scenario, knowledge arises in the learner which did not come directly from the teacher. Polanyi calls this "tacit knowledge".
2. Wikipedia's Charles Taylor uses the term "unarticulated background"
Following Heidegger, Merleau-Ponty, Hans-Georg Gadamer, Michael Polanyi, and Wittgenstein, Taylor argues that it is mistaken to presuppose that our understanding of the world is primarily mediated by representations. It is only against an unarticulated background that representations can make sense to us. On occasion we do follow rules by explicitly representing them to ourselves, but Taylor reminds us that rules do not contain the principles of their own application: application requires that we draw on an unarticulated understanding or "sense of things"—the background.
3. I haven't read Philosophical Investigations, but Wittgenstein's "form of life" seems to be another term:
While the term is often used in various ways by Wittgenstein, it connotes the sociological, historical, linguistic, physiological, and behavioral determinants that comprise the matrix within which a given language has meaning.
4. The sociology of knowledge gives us yet another term: "social fact", or "taken-for-grantedness". Sometimes this shows up as an inarticulable background: ask common folk why they participate in some activity and they may be unable to give you an answer that provides any deeper reason than that this is what they do, perhaps what makes them who they are.
5. Yet another term is "collective unconscious" or "collective representation":
For Jung, “My thesis then, is as follows: in addition to our immediate consciousness, which is of a thoroughly personal nature and which we believe to be the only empirical psyche (even if we tack on the personal unconscious as an appendix), there exists a second psychic system of a collective, universal, and impersonal nature which is identical in all individuals. This collective unconscious does not develop individually but is inherited. It consists of pre-existent forms, the archetypes, which can only become conscious secondarily and which give definite form to certain psychic contents.”
What are other terms or systematic treatments of this concept? I'll try to keep the list updated:
- "tacit knowledge"
- "unarticulated background"
- "form of life"
- "social fact"/"taken-for-grantedness"
- "collective unconscious"/"collective representation"
- "context" (Is there a definition for “context”?)
- "rule" (How do we know how to follow a rule?)
If you do not think the terms so far are sufficiently similar, please point that out as well.