It is well known that the Tractatus articulates a “picture” theory of meaning...

It is well known that the Tractatus articulates a “picture” theory of meaning, according to which a proposition has the meaning that it does in virtue of sharing an abstract structure or form with a possible state of affairs.[^107] Just as a visual picture, in order to depict a situation, must share its spatial form, any proposition whatsoever, in order to depict, must share with the possible or actual state of affairs for which it stands its “logico-pictoral” or “logical” form.[^108] A proposition is said to share the logical form of a state of affairs when there is an isomorphism between the relational structure of the proposition and the relational structure of the state of affairs; the fact that the elements of the proposition are related in a particular way represents the fact that things are related, in the state of affairs, in the same way.[^109] Wittgenstein emphasized that the logical structure of a proposition can be shown clearly in the arrangement of its constituent signs; we can imagine using physical objects, rather than written signs, in various spatial arrangements to depict possible situations.[^110] But propositions as they are written in ordinary language do not always show clearly the relational structure of their logically simple elements.[^111] One task of philosophical criticism or analysis, accordingly, is to articulate these elements by rewriting ordinary-language propositions in a perspicuous notation that shows through its symbolism the logical relations that propositions express.

Many commentaries on the Tractatus are content to leave matters here, with the Tractarian picture theory of meaning explained as a metaphysical theory of the meaning of propositions in terms of their articulation as relational structures of signs.[^112] In so doing, although they often appeal to the analogy that Wittgenstein suggests between the spatial form of an ordinary picture and the logical form of a proposition, they typically leave the metaphysical underpinnings of the central notion of logical form somewhat obscure.

A proposition’s meaning is said to consist in an “abstract” or “formal” correspondence between the relational structure of signs in a proposition (once these are logically articulated by analysis) and the relational structure of simple objects in a state of affairs. But it is not said what this correspondence amounts to, or how to recognize when a proposition has been articulated, through analysis, enough to make it perspicuous.