I think the more interesting suggestion is that the effective “we” when we talk about what “we” have access to, is, indeed, we—not just I, but you and me. It is, more particularly, your access to my mind that simplifies the information that we have access to!
The linguist Stephen Levinson (2006) has studied the remarkable language, Yélî Dnye, of the three thousand or so inhabitants of Rossel Island in the South Pacific—to the north of Papua New Guinea. It is a completely isolated language, unlike any other in the world in many regards. In particular, it is hideously complex, with:
the largest phoneme inventory (ninety distinct segments) in the Pacific, and many sounds (such as doubly articulated labial coronal stops) that are either unique or rare in the languages of the world. Among the fifty-six consonants are many multiply articulated segments: e.g., /ţpņm/ is a single segment made by simultaneously putting the tongue behind the alveolar ridge, trilling the lips , and snorting air through the nose. […] Once the learner is past the sound hurdle, he or she faces another formidable obstacle. The language has an extremely complex system of verb inflection (with thousands of distinct inflectional forms). […] In addition, substitute forms are used where the subject has been mentioned before, is close or visible, is in motion, or where the sentence is counterfactual or negative, thus providing well over a thousand possibilities […]. (Levinson 2006, p. 20)
Levinson reports, not surprisingly, that “[h]ardly any mature individuals (such as non-native spouses) who have immigrated into the island community ever learn to speak the language, and children of expatriate Rossels do not fully acquire it from their parents alone.” His explanation is speculative, but plausible: a language, left to itself for centuries, will grow ever more complex, like an unpruned bush, simply because it can. The extreme isolation of Rossel Island over the centuries (for various geographic reasons) means that the language has hardly ever been confronted with non-native speakers of another language with whom communication is imperative, for one reason or another. The need for communication soon generates a small cadre of bi-lingual interpreters, and maybe also a pidgin (and maybe later a creole), and all of these alien interfaces work to simplify a language. The least learnable, most baroque (in the sense of exceeding the functional) features of the language are dropped under this pressure. We can see it happening with English today, with simplified dialects such as Emblish (as spoken at the European Molecular Biology Laboratory in Heidelberg) arising naturally and imperceptibly.
I would like to speculate that a similar process of gradual but incessant simplification has shaped the language we have available to explain and describe our minds to each other. Wittgenstein’s famous claim about the impossibility of a private language has not weathered the storms of controversy particularly well, but there are neighboring claims—empirical claims—that deserve consideration. Many years ago, Nicholas Humphrey (1987) made the point that has begun to attract adherents today:
While it is of no interest to a person to have the same kind of kidney as another person, it is of interest to him to have the same kind of mind: otherwise as a natural psychologist he'd be in trouble. Kidney transplants occur very rarely in nature, but something very much like mind-transplants occur all the time […]. [So] we can assume that throughout a long history of evolution all sorts of different ways of describing the brain's activity have been experimented with but only those most suited to doing psychology have been preserved. Thus the particular picture of our inner selves that human beings do in fact now have—the picture we know as ‘us’, and cannot imagine being of any different kind—is neither a necessary description nor is it any old description of the brain: it is the one that has proved most suited to our needs as social beings. That is why it works. Not only can we count on other people's brains being very much like ours, we can count on the picture we each have of what it's like to have a brain being tailor-made to explain the way that other people actually behave. Consciousness is a socio-biological product—in the best sense of socio and biological. (p. 18)
Chris Frith, for instance, has recently taken up the theme (in conversation) that consciousness has some features, because everything in consciousness has to be couched in terms that can be communicated to other people readily.
The ineffability barrier we all experience when trying to tell others what it is like to be us on particular occasions is highly variable, not just between individuals, but over time within a single individual, as a result of formal or informal training. It plays a dynamic role in shaping the contents of our consciousness over time.[5] (This would be true only for human consciousness, obviously.)