A language is a symbol system, but some words are relatively indexical. Pronouns, by directing attention to specific individuals in a context rather than general types, work indexically better than nouns do.
It is impossible to express what an assertion refers to except by means of an index. A pronoun is an index. A noun, on the other hand, does not indicate the object it denotes; and when a noun is used to show what one is talking about, the experience of the hearer is relied upon to make up for the incapacity of a noun for doing what the pronoun does at once. Thus, a noun is an imperfect substitute for a pronoun.… A pronoun ought to be defined as a word which may indicate anything to which the first and second persons have suitable real connections, by calling the attention of the second person to it.
— Peirce (EP2:15 fn., emphasis his)
The thing to which a pronoun calls attention must exist in the situational context of both of these persons in order for communication to succeed. In order for a noun (even a proper noun) to direct attention to the object of a symbol such as a sentence, the prior experience of the hearer is called upon – not only her memory of prior language usage, but also her memory of previous acquaintance (collateral experience) with the object of the symbol. This memory makes the difference between ‘the inexperienced and the experienced person meeting the same man and noticing the same peculiarities, which to the experienced man indicate a whole history, but to the inexperienced reveal nothing’ (EP2:8).
The ‘experienced’ reader of a text (i.e. the reader well acquainted with its context) will also notice ‘peculiarities’ which not only ‘indicate a whole history’ but also point to previously unnoticed relationships among parts of that object recalled to memory. My ‘real connection’ with a place becomes more finely articulated as i walk through it, even if i have taken that same path before, as long as i am attentive to its twists and turns on this walk. In my experience, reading and re-reading the works of a writer such as Peirce can likewise sharpen the sense of what he is writing about. For the ‘experienced’ reader, the very nouns in that text can act more like pronouns, drawing renewed attention to features of its object in order to regenerate its interpretant. No book can transmit acquaintance with such a ‘whole history’ or whole system; yet the writer works in the hope that some future reader may be able to recreate or resurrect it.