It is an embarrassment to philosophers that they cannot define their discipline. It makes them look like shady operators. I propose to alleviate their embarrassment by offering a succinct definition of philosophy.
If you ask a physicist what physics is about, he will say that it is about physical reality, and you will learn what physics is. If you ask a psychologist what psychology is about, she will say that it is about the mind, and you will learn what psychology is. Similarly for geography, astronomy, botany, history, etc. But if you ask a philosopher what philosophy is about, you will not get such a straightforward answer—instead you will be subjected to vague mutterings about our conceptual scheme or incipient science or language or Being. You will rightly protest: “But what is it about?” The other disciplines can tell you what sector of reality they concern, but philosophy seems not have a specific sector to call its own—it seems to include both everything and nothing. This is theoretically unsatisfactory and bad PR. Every discipline is defined by the properties and relations that constitute its subject matter, but philosophy seems like the odd man out—the exception to the rule. What sector of reality does it take as its own? Don’t say “all sectors” because that is merely mystifying, and makes it look like it is all the disciplines added up, which it certainly is not.
It used to be said, perhaps a touch defensively, that philosophy is about concepts (or possibly the language in which concepts are expressed): it deals with the property of having a concept and with relations between concepts. The trouble with this answer is that it makes philosophy sound like psychology, and as a consequence not about the world beyond the mind. We need to say what it is about concepts that renders them of philosophical relevance. The answer might be returned: the analysis of concepts. Again, that is not entirely on the wrong track, but what kind of analysis? Isn’t analyzing psychological entities just more psychology (compare psychoanalysis). Similarly if we prefer to talk about language: what then makes philosophy differ from linguistics? What kind of analysis characterizes philosophy? The obvious answer is logical analysis. But this formulation describes the method of philosophy not its subject matter (imagine a physicist saying “physics is about the analysis of matter”). I propose that we make the obvious amendment: philosophy is about logical reality—as physics is about physical reality. That is the sector of reality with which philosophy is essentially concerned—the logical sector. The use of the word “reality” in this style of answer is intended to contrast the concern of the practitioner with such things as the concerns of a fiction writer: the scientist is concerned with reality not fantasy (like the science fiction writer). So the philosopher, being a sober factual type, is concerned with a certain part of reality—the part I am calling “logical”. Thus when asked what philosophy is about the philosopher can answer simply, “Philosophy is about logical reality”—as physics is about physical reality, psychology is about mental reality, history is about historical reality, etc.
Of course this short answer will not put an end to all questions, just as the comparable answer for other disciplines may well prompt further questions. We will need to say what we mean by “logical”, as the physicist needs to say what he means by “physical”. The correct answer, though not perhaps the best pedagogically, is that logical reality consists of all the relations of entailment, consistency, and inconsistency that exist. An example might help: the philosophical problem of free will concerns whether free will logically implies determinism or indeterminism. Thus we have compatibilists and incompatibilists debating the logical relations between free will and these other concepts. Some say free will rules out determinism, some say the two are compatible, and some say that free will logically implies determinism. Philosophy therefore differs from psychology and physiology when it comes to acts of will, being concerned with a logical question. Here are some other examples chosen more or less at random. Does the mind entail the body or are the two logically separable? How are sense experience and material objects logically related? Is knowledge logically compatible with non-conclusive evidence? How are mind and behavior logically related? Are truth and meaning logically connected? Do descriptive propositions ever entail ethical propositions? Does identity of reference entail identity of sense? Do modal propositions entail the existence of possible worlds? Do general terms logically imply abstract universals? Does death entail the end of the soul? Does survival of persons require identity through time? Are causation and constant conjunction mutually entailing? These questions are the stuff of philosophy and they all concern what I am calling logical reality; so our definition of philosophy looks to be on the right lines.
There can be different theories of logical reality: some say it involves concepts, some say it is a matter of words, others say that it is about reality itself (this is my position). Never mind: philosophy is about whatever logic is about. Note that I am adopting a very broad notion of logic here—certainly not restricted to standard propositional and predicate calculus. Logic in the broad sense includes any type of consequence relation—entailment in the most capacious sense (but it has to involve necessity). What is important is that this sector of reality exists and can be studied. In addition to physical objects, psychological subjects, biological forms, historical epochs, and geological strata, there is a realm of logical relations along with their relata (whatever we determine these to be). Let’s adopt for the nonce full-blooded realism about this sector: there is an objective mind-independent logical reality into which we can inquire. Like other regions of reality it can be difficult to penetrate, presenting puzzles and mysteries, and be capable of leading us up the wrong track (some have said that our ordinary language distracts us from its actual nature). So we might want to preface our answer to the question of what philosophy is by remarking, “Well, there is something called logical reality, which is a genuine part of what there is, though there are debates about its nature…and philosophy studies that”. It might help to soften the inquirer up by saying a few words about mathematics or even logic itself (i.e. the subject of a typical logic course). But don’t spend too long on these preliminaries, just blurt it out without hesitation and in a confident no-nonsense voice: “Philosophy is the study of logical reality”. This should obviate the shady operator suspicion and pave the way for a healthy and fruitful discussion. It is also entirely accurate.
One nice feature of this definition is that it does justice to the breadth of philosophy: philosophers talk about everything, though from a specific point of view. For everything has entailments, logic being universal. For instance, if you are investigating the logic of identity, you will be dealing with everything that exists, since everything is self-identical. This gets philosophy a reputation for being “abstract”, dubiously airy-fairy: but you should resist this idea. Philosophy has a perfectly solid subject matter, given that logical reality is real: entailment is as real as the things it relates. We investigate it by employing the faculty of reason, not the sense organs, but that doesn’t detract from its reality (compare mathematics). Reasoning is the method whereby logical relations are exposed. There is thus no objection to rephrasing our definition as follows: “Philosophy is the study of rational structure”. Logic deals with what is rational, so philosophy is concerned with the domain over which rationality operates. I prefer the blunter “logical reality” for reasons of rhetoric, but “rational structure” can be offered as a useful gloss (but beware of its psychologistic connotations). In any case, the general conception is consonant with the generality of philosophy. But this is not an indication that philosophy has no subject matter to call its own, only that its specific subject matter extends over all of reality (in this sense philosophy is a “higher-order” discipline). We might picture philosophy as lying alongside the other sectors of reality studied by the various disciplines, so that we have such philosophical topics as philosophy of history, philosophy of mind, philosophy of physics, philosophy of knowledge, etc. It is not that philosophy somehow includes these other subjects (it is not history, psychology, physics, etc.); rather, it studies the logical relations into which these various subject matters enter. It studies, for example, the logical relations between physics and biology or history and psychology (as well as logical relations existing within those disciplines).
What are the paradigms of philosophy as so conceived? I hesitate to single certain philosophers out because that may suggest a tendentious picture of the discipline, but Frege and the Wittgenstein of the Tractatus make good examples. Consider Frege’s apparatus of sense and reference, of objects and functions, and Wittgenstein’s vision of reality as a logical space fixed by logical language. The world is depicted as a logical structure into which we may inquire. At the other extreme we have Hegel’s dialectical theory of the logic of history, or Sartre’s investigation of being and nothingness (consciousness entails a “nothingness at the heart of being”). Husserl’s Logical Investigations deals with the logical structure of mental acts. Grice’s work tells us that conversational implicature does not entail logical implication. Quine assures us that a behaviorist view of meaning entails indeterminacy. Kripke contends that names don’t imply descriptions. Rawls argues that justice entails fairness. And so on. A philosopher is always concerned with what follows from what, and what does not follow. Problems arise when reflecting on our knowledge of the world—logical problems—and we strive to solve these problems by reasoning. We try to get a clear view of logical reality (whether bewitched by language or not).
Philosophy so understood is not confined to mere description. It can be revisionary, even radically so. There may be hidden implications that undermine parts of common sense or even science. There may be lurking paradoxes that call whole areas of thought into question. Such is the way of skepticism: if we examine the logical nature of knowledge we see that it is inconsistent with many of our knowledge claims—it implies certainty where none is to be had. Truth may turn out to entail its own negation, as in the semantic paradoxes. Modality may imply an unacceptable metaphysics. So logical reality may diverge from the way it seems to us in common sense, requiring revisions in our conceptual scheme (maybe free will turns out to be impossible given its entailments). Logical reality may be difficult to discern, and not what we expect: so there is nothing quietist about this conception of philosophy.
If philosophy is about logical reality, it is centrally about linkages—its focus is on connection. It wants to know how things hang together, or fail to. It is always interested in how things are related, joined or disjoined. But it is not concerned with physical or psychological linkages, but with logical linkages. In the philosophy of free will, for example, the concern is less on free will itself as on how it is related to determinism (or indeterminism)—how are these things linked? Likewise we want to know about the linkage between mind and body—whether the mind logically precludes emergence from the body or not. So philosophical acumen largely consists in the detection and articulation of such logical linkages—in seeing what follows and does not follow. That’s what you’ve got to get good at. That’s what you’ve got to be interested in. The philosopher is a linkage enthusiast, an artist of logical connection (scientist too).
It is tediously repeated that philosophy used to include the sciences till they found their independence, and that the rest of philosophy will eventually go that way, disappearing up its own success. But if what I have said here is correct, this will not happen; and it betrays a fundamental misunderstanding of the subject to think that it will. For philosophy is concerned with the linkages that constitute logical reality, and no other discipline is so concerned. Just as logical reality will never collapse into other areas of reality, so philosophy will never be replaced by the disciplines that study those other areas.