The Meta-Linguistic Turn
Suppose you are interested in the nature of numbers or causation or necessity or the mind or values. Your interests are traditionally metaphysical or ontological. You propose to think about these things and try to come up with answers. But someone tells you that you are going about it the wrong way: you should really focus on sentences or statements about these things—you should think about linguistic entities instead. You should analyze these sentences, give their logical form, and specify how they are used, engaging in syntax, semantics, and pragmatics. Then you will shed light on numbers, causation, necessity, mind, and value. You should take the “linguistic turn”, which will provide a methodology and a concrete focus: statements not facts, words not objects. You will be studying the world as it is represented in language.
But how should you study language in order to pursue your metaphysical interests? Not as a linguist might or a psychologist or a neurologist: you are not interested in these kinds of empirical questions qua philosopher. You are interested in the meaning of the sentences in question, the better to understand what they refer to (numbers, causal relations, etc.). So your methods are not those of the linguist or psychologist or neurologist (you don’t, for example, examine the brain of the user of these sentences). No, what you investigate is the way we ordinarily understand the sentences in question: you analyze their meaning, dissect their structure, and describe their standard use. We might say that you engage in conceptual analysis, understood broadly. You do this by talking about sentences, i.e. you employ a meta-language. This will involve you in using semantic concepts (as well as syntactic and pragmatic concepts): you will use the concepts of meaning, reference, entailment, truth, assertion, criterion of application, etc. In the case of statements of number, for example, you will note that numerals look like singular terms with reference, that some numerical expressions operate as quantifiers with domains of quantification, that “2+2=4” is true if and only if 2+2=4, and that arithmetical statements are grammatical and meaningful. This will bring you to consider the significance of such meta-linguistic sentences: what does it mean to say that a sentence is meaningful, or that it has this or that specific meaning, or that a word refers to an object, or that a sentence is true? You will unavoidably be drawn to consider meta-linguistic language, specifically the analysis of semantic expressions. You will be considering the theory of meaning and reference. For example, you will wonder how the causal theory of reference relates to statements of number, or whether it is possible to refer to a private sensation, or whether names are descriptions, or whether meaning consists in truth conditions. In other words, you can’t do philosophy of language without examining meta-linguistic sentences: you must not only use them in talking about words and sentences, you must understand them—they must become a direct focus of interest (mentioned not used). In understanding language you must understand language about language—and understand it philosophically. Most centrally, you will be concerned to understand sentences of the form, “s means that p”. Put simply, you will want to analyze the word “means”. And, of course, much philosophy of language is precisely concerned with such locutions and sentences—it is interested in meta-linguistic sentences. This is because it is interested in semantic concepts. So the philosophy of language is concerned with sentences and with sentences about sentences: with both the object language and the meta-language. How could it not be concerned with the meta-language?
Thus the linguistic turn involves a meta-linguistic turn: when we turn from the world to language we also turn from language to language about language. And this second-order language is part of our normal conceptual repertoire: everyone who speaks a human language also speaks a meta-language about that language. We all have the concept of meaning and associated concepts; these are not novel theoretical terms introduced by a groundbreaking scientist, like “quark” or “gene”. We recognize the central terms of art of the philosopher of language as our own; indeed, these terms are as natural and innate as the object language itself. Not only do we acquire a language (an object language) with great ease and speed; we also acquire a meta-language with comparable ease and speed. Language about language is part of our natural endowment as human beings. This means that our competence in such language can be used to develop theories of language: our intuitions about the concept of meaning, say, can be used to test theories of meaning. So the meta-linguistic turn is entirely natural to us: it embodies knowledge that we have as a matter of course. We understand our first-order sentences but we also understand our second-order sentences; it is not that we start struggling when language turns back on itself–as if the word “means” throws us into disarray, as “quark” might. So the meta-linguistic turn is methodologically sound so far as our linguistic knowledge is concerned, and it seems essential to the linguistic turn as a whole. The linguistic turn necessarily brings with it the meta-linguistic turn. Accordingly, when we turn from causation itself, say, and look at causal statements, we inevitably look at statements about causal statements, especially statements invoking the concept of meaning. The general theory of meaning thus becomes relevant to the theory of causation once the linguistic turn has been made. You can’t understand what a cause is without knowing what meaning is! Whether this counts as a welcome result or a reductio of the entire approach is another question; the point is that the linguistic turn leads us in that direction. Metaphysics and semantics become inextricably intermingled: facts can only be understood if meaning can be, i.e. meta-linguistic statements concerning meaning. This makes metaphysics quite different from physics, say, because no one thinks that we can’t do physics without a theory of meaning to guide us.
The case is similar with the epistemic turn: if we shift our focus from facts to knowledge of facts in the hope of getting a better handle on facts, we will inevitably be led to consider our knowledge of knowledge. We won’t bring in what a psychologist has to say about knowledge (as in the psychology of education) but will concern ourselves with our ordinary grasp of knowledge—for example, that knowledge involves truth and justification and that it is vulnerable to skepticism. This is meta-knowledge—knowledge about knowledge. We use this meta-knowledge in order to understand knowledge itself (first-order knowledge), but we will find ourselves examining meta-knowledge in its own right—we will take it as an object of investigation. Are we right to suppose knowledge involves truth and justification and that it is vulnerable to skepticism? Perhaps we don’t know enough about knowledge to be confident about such things. Are we epistemically perfect with respect to our epistemic capacities? What is the nature of knowledge of knowledge? Is it caused by knowledge? Is it perceptual? How fallible is it? Thus we engage in an examination of meta-knowledge as part of the epistemic turn; we can’t just stop at first-order knowledge itself but must proceed up a step to consider our knowledge of knowledge. That is what philosophers do—investigate the questions that are raised by their methods. So the epistemic turn will involve us in questions about meta-knowledge: we can’t know what causation is, say, without understanding our knowledge of causal knowledge! We can examine how we come to know causal facts, but that will bring us to wonder about what we know of our knowledge of causal facts. Thus the epistemic turn involves a meta-epistemic turn. Again, whether this is a welcome result or a reductio is another question; the point is that the epistemic turn turns into a meta-epistemic turn. Combining the epistemic turn with the linguistic turn, we are not just interested in sentences like “A knows that x caused y” but also sentences like “A knows that B knows that x caused y”. Our knowledge of our causal knowledge might or might not be adequate, but we must assume that it has some veracity in order to invoke our understanding of such knowledge in the effort to understand causation. We end up scrutinizing our higher-order knowledge in the project of getting clearer about causation. We have some understanding of what knowledge is just by having the concept, which is why people can recognize the correctness of elementary truths about knowledge; but that is not to say that the theory of knowledge is all plain sailing. So the epistemic turn in metaphysics will find itself caught up in questions about our knowledge of knowledge. Whether that counts as philosophical progress is an interesting question; certainly it complicates the claim of the epistemic turn to constitute a royal road to metaphysical understanding. It isn’t as if everything becomes clear once we turn our attention to causal knowledge and away from causation as such (and similarly for the other topics listed).
The same is true for the conceptual turn: here too the shift from things to concepts of things will involve us in meta-questions about concepts, and it is not as if that subject is all goodness and light. Concepts about concepts, thoughts about thoughts, also require scrutiny. The conceptual turn becomes a meta-conceptual turn with all the questions that entails. A person might be forgiven for supposing that we had it easier when we were trying to focus on facts directly. Is it really easier to understand our concept of necessity (say) than necessity itself? Why turn from the frying pan to the fire when the fire is even hotter? In any case, meta-questions about concepts will accompany the conceptual turn. When we turn from things to concepts in order to understand the things better we will inevitably face the question of how to understand concepts: and the latter may be no more pellucid than the former.
Original proponents of the linguistic turn probably thought that language was a relatively problem-free zone compared to traditional metaphysics, so it could be reliably turned to in times of need. Aren’t statements about numbers more straightforward than numbers themselves? We can at least see and hear them, and write them down. Thus Frege’s advice to begin with the former and work back to the latter looks sensible enough. But one look at the theory of language espoused by Frege deflates that expectation, what with its apparatus of sense and reference, concept and object, function and argument, truth-values as objects, thoughts as objective platonic entities, saturated and unsaturated entities, infinite hierarchies of indirect sense, etc. Indeed, the ontology of the theory invites questions comparable to those raised by traditional metaphysics concerning numbers. The meta-language propositions of Frege’s theory of language are as puzzling as any in traditional metaphysics. So the meta-linguistic turn reveals the linguistic turn to be not on such solid ground as it might have hoped. In philosophy as in life, when you turn from one thing to another, be fully cognizant of what you are turning to.
 It may be said that second-order knowledge is more reliable than first-order knowledge and less vulnerable to skepticism: we can be more certain that first-order knowledge is vulnerable to skepticism than that we are not brains in a vat. But the determined skeptic might insist that this purported knowledge of the truth of skepticism is not as solid as we suppose: we might have made a slip in our reasoning or the concept of knowledge might not be as demanding as the skeptic supposes. At any rate, such questions would have to be posed once we examine second-order knowledge.