The Metaphysics of Meaning.
Katz's approach builds on a foundation of "folk semantics", the idea that we commonly speak about meanings and their relationships ("e.g., synonymy, antonymy, ambiguity, redundancy, similarity in meaning, meaningfulness, and meaninglessness" (p. 30)), that such talk need not entail or assume any particular conclusions about the ontology or epistemology of meaning (p. 82), and that any semantic theory should try to explain these "facts" about meaning. His argument is that only an intensionalist approach succeeds in doing so.
Katz repeatedly argues that the purported refutations of intensionalism in the literature apply only to Fregean versions of intensionalism. He accepts that Fregean theories are vulnerable in the ways that have been asserted by various critics, but he believes that a form of intensionalism can be put forward that does not suffer from the same weaknesses. Katz criticizes Frege for having falsely joined semantics and logic in his analysis of analyticity and necessary truth, that is, for not maintaining a sufficiently sharp distinction between sense and reference (pp. 70-71). Katz believes that sense should not be seen not as "determining" reference, but only as "mediating" reference (p. 90) (a point which will be discussed further below).
The form of intensionalism Katz puts forward as the best explanation of semantic facts he calls the "proto-theory", in that it is "only a first approximation to a full theory of decompositional sense structure" (p. 66). The various related devices he uses to defend that theory against Wittgensteinian and Quinean critiques include not equating senses either with extensional (psychological) objects or with referents (p. 33), distinguishing semantics from pragmatics (pp. 90-93) and sentence types from sentence tokens (p. 39), and offering a decompositional semantics (such that even "syntactically simple words" can sometimes have a semantically complex, decompositional structure" (p. 7 1)). Katz's semantic theory is "top-down", in that analysing the meaning of a particular utterance begins with the meaning of a type as affected by various extralinguistic and extragrammatical factors. In response to the Kripkean question of what (kind of) fact determines the meaning of a particular utterance, he offers the "mixed fact... compounded of a grammatical fact about the language and a psychological fact about its speakers" (p. 144).
Katz's arguments against Wittgensteinian and Quinean theories of meaning are similar in structure: he claims that both theories based on use and theories based on reference have counter-intuitive elements and would not be tenable unless it had first been shown that the alternative intensionalist approaches to meaning were not defensible (e.g., pp. 37-43, 204-10). He considers Wittgenstein's arguments in the first part of the Philosophical Investigations (up to and including the material on rule-following) with great care, almost paragraph by paragraph, in order to show that Wittgenstein's attempted universal critique, which purports to refute all theories of meaning, at no point succeeds in refuting Katz's own theory.
Katz claims that most of the current influential theories about language, including those of Donald Davidson, Tyler Burge and Hilary Putnam, depend upon (and assume) the validity of Quine's conclusion that there are no linguistically neutral meanings, and thus that no objective sense can be made of the intensionalist's notions of sense (pp. 176, 182). Katz claims that the only place where Quine argued for this conclusion was in "Two Dogmas of Empiricism" (pp. 175-86). In that article, Quine considered what he thought were the three possible approaches to "meaning" - approaches based on definition, logical theory and linguistic - each was found wanting. Katz accepts much of Quine's discussion, but claims that Quine's argument against a linguistics-based approach to meaning was faulty, because based on an out-of-date and ineffectual approach to linguistics (substitution criteria). Katz argues that the current approach to linguistics (generative grammar) would not be vulnerable to Quine's attacks (pp. 187-92). According to Katz's "domino theory", once this attack on a linguistic analysis of meaning fails, Quine's critique fails, and the approaches of Davidson, Burge, and many others are fatally undermined (pp. 203-33). Putnam's additional, independent attack on intensionalism, from his article "The Meaning of "Meaning'" (and elsewhere), is said to fall short because it assumes that all intensionalists must take up a Fregean position that sense determines reference, which Katz's "proto-theory" does not do (pp. 219-20).
Katz's argument for non-naturalism generally in philosophy is based on principles used to evaluate scientific theories: "the standard methodological canons for determining how well theories account for the phenomena in the domain" (p. 244). Between selecting this method for choosing between approaches and care- fully selecting which phenomena must be explained, it is not surprising that non-naturalist theories appear superior to their naturalist competitors. For example, using criteria like "simplicity" (p. 263), non-naturalist theories, in positing abstract objects, appear to account better or more directly for the "facts" of logical necessity, mathematical entities, and moral conclusions, while naturalist theories will always appear awkward and cumbersome, trying to explain those "facts" in terms of inclinations, mental states, and the like.
Generally, Katz can be seen as trying to find a middle position with his "proto-theory". On one extreme is the Wittgensteinian position that looks only or primarily to use, and which thus resists theory because no theory would be able to contain the relative disorder and constant flux of language in use. The Wittgensteinian position has all the advantages, and all the disadvantages, of a purely descriptive exercise; some see it as merely an excuse for those who lack the patience, imagination or discipline necessary for true theory, for true "science". Those who favour general theories of meaning would point out that there seem to be enough patterns and regularities within language (and some linguists would add, enough similarities among languages) to make an the creation of a general theory worth attempting.
The problem with the position at the other extreme is that it is difficult to create a general theory that is sufficiently complex to explain all facts of utterance meaning and reference while still being sufficiently simple to be useful. Katz's middle position is to posit a theory that attaches objective meanings - literal meanings - to words, but allows that what these words actually mean and actually refer to in particular utterances will depend on a variety of factors, of which the objective (literal) meaning is but one. However, if so much of language use has to be attributed to "extralinguistic" (pp. 44-47, 113) and "extragrammatical" (p. 90) factor that is, factors not explicitly covered by the theory of meaning - one wonders how valuable the theory is (and whether its potential disadvantages might outweigh its advantages). In comparison with the two extreme approaches to theories of meaning, one might wonder whether Katz's example offers the best of both worlds or the worst of both worlds.
One might also suspect that the "proto-theory" is too cumbersome a machine to get off the ground - here are too many gadgets added to avoid other theorists' criticisms. The parts of the machine which must do the greatest amount of work philosophically are also the parts which seem the weakest: the mediation of references and the faculty of intuition. The connection between sense and reference in the "proto-theory" is said to be one of "mediation" rather than determination, though what "mediation" means here is never explained in detail, other than by pointing out that it allows for "extragrammatical information" in explaining why "the meaning of [a particular] utterance departs, even perhaps radically, from the meaning of its type" (p. 90). However, "mediation" is sufficiently central to Katz's alternative theory (and its ability to survive anti-Fregean criticisms) that further clarification is needed.
Though Katz concedes that non-naturalist theories have difficulty in explaining how we come to know about abstract objects, his response does not allay all doubts. Katz believes that we "grasp" abstract objects through intuition (p. 255). His argument for the existence of such a faculty is primarily indirect: a great deal of information we have or use - in particular the principles basic to the way we reason in (e.g.) mathematics and logic - could not have been obtained in any other way (pp. 283-90). However, those who are sceptical about the knowledge of intensional objects need to be told more than (in effect) "if you (implicitly) accepted intensional objects in other areas you cannot object to their use here."
One final matter: it is a minor, but irritating fault of this book that it lacks a bibliography. The full citation of a reference is given only once: when it is first mentioned in the endnotes. All subsequent mentions of the same source offer neither full citation information nor a cross-reference to the endnote where the information was given. It can thus be quite difficult to find relevant citation information.
Whatever its faults, The Metaphysics of Meaning offers a provocative overview of philosophy of language, both in the book's critical discussion of other theories and in its positive programme. It certainly warrants more attention than it has so far received.