Philosophy and Common Sense 1: What Is Common Sense?

Sebastian Sunday-Grève and Timothy Williamson discuss the question of where philosophy starts and the idea of philosophy as a non-natural science

Common Sense or Curiosity?

Sebastian Sunday-Grève

Timothy Williamson tells a story of the naturalness of philosophy -- that is, of how natural it is to engage in doing philosophy. This is an important kind of story to tell, because philosophy tends to seem unnatural to many people, and hence their opinion of it is rather low. It is of course not very surprising that they can easily have this impression, given some of the claims typically made by philosophers, such as that nothing ever changes (Parmenides), that everything constantly changes (Heraclitus) or that “the nothing noths” (Heidegger). Perhaps Williamson’s own view that vagueness is a form of ignorance is another example, insofar as it entails that one hair can make the difference between being bald and being not bald.

Be that as it may, the story Williamson tells is compelling. Part of the reason why it is compelling is that when he tells it he is practising what he preaches. By developing his account of the naturalness of philosophy in this way, Williamson is of course engaged in doing philosophy himself, and he manages to do this bit of philosophy in exactly the way that he says should be possible. Williamson argues that all it takes for an individual in suitable circumstances to engage in doing philosophy is curiosity and common sense. And in attempting to show this, he does indeed appear to be relying on nothing but these two basic ingredients. Thus, his account appears to be doubly demonstrated: the way in which he presents its general claims appears at the same time to constitute an instantiation of them.

To be sure, the apparent reliance on nothing but his own common sense and curiosity in presenting the account must be regarded as a considerable feat, even if Williamson is right that philosophy normally requires no more than that. Developing an account of the cognitive basis required for an individual to engage in doing philosophy is not itself the sort of thing that philosophy starts with for an individual. On the contrary, it is a rather more advanced step: developing a plausible account of the matter and presenting it in a clear and precise fashion, as Williamson has done, is no easy task for even the most experienced philosophers.

Williamson begins by telling us that a natural answer to the question of where philosophy starts is “common sense”. He then offers various explanations of what he takes common sense to be, which can be summed up by the following three equations:

Common-sense knowledge = widely shared knowledge

Common-sense belief = widely shared belief

Common-sense cognitive methods = widely shared cognitive methods

But looking at these three equations has made me wonder why the notion of common sense is even employed. In this context, “widely shared” appears to mean just the same as “common”. Thus, it seems it might have been the better choice to speak simply of common knowledge, common belief and common cognitive methods instead of common-sense knowledge, common-sense belief and so on.

While trying to figure this out, I thought about how “common sense” is typically translated into German, namely as gesunder Menschenverstand, literally “healthy human reason”. Williamson does not, however, want to restrict common sense to humans. In fact, he argues that common sense and curiosity, the only two requirements he has mentioned for getting philosophy started, can also be found in non-human animals. So can non-human animals perhaps engage in doing philosophy too? Where would Williamson draw the line? And how? Is it perhaps a matter of degree of common sense or curiosity, or is there something else to the cognitive basis required for philosophy (such as language, for example, which he says “enables us to construct more abstract questions, to become curious about more abstract matters”)?

The same consideration applies to curiosity. If, however, Williamson’s intention is indeed to give nothing but a natural answer to the question of where philosophy starts, in order to suit his narrative, then will it not perhaps be the case that curiosity could serve equally well as the sole driver of the story? That is, not as an answer to the question of what more is required for philosophy, in addition to common sense, but as a better answer instead of this first one? For does not curiosity, on Williamson’s plausible definition of it as an appetite for knowledge, entail enough of that which he wishes to pick out by “common sense”? After all, you can only have an appetite for knowledge, if you have at least some knowledge already. And, as regards common-sense cognitive methods, it can perhaps be granted that an individual with an appetite for knowledge is normally capable of acquiring new knowledge. So, it seems, the story might perhaps be told even better simply in terms of curiosity.


Common Sense, Curiosity, and Language

Timothy Williamson

In “Common Sense or Curiosity?”, Sebastian Sunday-Grève asks whether common sense is needed to get into philosophy: why isn’t curiosity, understood as the appetite for knowledge, enough?

Cats and dogs are curious, as are animals of many other species, including humans. The appetite for knowledge has an obvious evolutionary explanation. Knowledge of your environment comes in useful in all sorts of ways. You need to know where you can get food or drink, you need to know about potential sexual partners. Unsurprisingly, anything new tends to excite curiosity, because it may indicate danger or opportunity. What made that unfamiliar smell?

Of course, an appetite for knowledge enhances your evolutionary fitness only if you are capable of satisfying that appetite. Thus we can expect curiosity to be accompanied by a capacity for acquiring knowledge. Sebastian goes further: “you can only have an appetite for knowledge, if you have at least some knowledge already.” That is not automatic. After all, an animal can have an innate appetite for sex before it has ever had sex, otherwise it might never get started. But animals typically get a stream of knowledge of their current environment through their senses – sight, hearing, touch, smell, taste, … – whenever they are awake, so if you have an innate appetite for knowledge, you probably have lots of knowledge already. Moreover, you presumably acquired most or all of that knowledge in ways which you have in common with other members of your species. Those ways are common-sense cognitive methods in my sense. If you belong to a social species, as you do, much of your local knowledge is probably shared with other members of your group. That is common-sense knowledge in my sense.

But then, if curiosity and common sense suffice for getting into philosophy, we face Sebastian’s question: “can non-human animals perhaps engage in doing philosophy too?” One would have to be rather besotted with one’s cat or dog to think that it has philosophical thoughts. Non-human animals sometimes look wise – owls famously do – but that is surely our projection. Some people look wise until they start talking. That brings us to the question of language.

Knowledge without language is possible. If a cat didn’t know where a mouse was, she couldn’t catch it. In knowing where it is, she knows something like: it’s there. She has that knowledge while unable to put it in the English words “It’s there”, or any other words. We speakers of a language use our words to describe what the cat knows, but the cat can know it without describing her knowledge. Languageless animals may even have some general knowledge, for example about which types of plant are good to eat.

Curiosity may involve asking oneself questions. If the mouse disappears, the cat may wonder where it has gone; we can describe her as asking herself: where’s it gone? She can do that without using the English words “Where’s it gone?”, or any other words. Presumably, if the cat were not wondering where the mouse has gone, she would not be looking around for it. Perhaps a pig can even wonder whether some newly encountered type of thing is good to eat.

Still, there are limits. It’s not that cats and dogs aren’t curious enough to ask themselves philosophical questions; they seem pretty much as curiosity-driven as humans are. Rather, the point is that, whatever form thinking takes in languageless animals, its content seems to be very closely related to sense perception and action, far more closely than a philosophical question would be. For example, if the cat asks where’s it gone?, her ability to do so presumably depends on her capacities for spatially organised perception and action, but those capacities do not enable her to ask the abstract question “What is space?”.

Of course, language too may well have originated in ways closely related to sense perception and action. Linguistic communication still depends on hearing, when we listen to what someone says, on sight, when we read what they write, and on touch in the case of braille. Still, what a word means normally doesn’t depend on its sound, and once we have a language, we can manipulate its words to form all sorts of new combinations, with meanings which might never have occurred to us otherwise. In that way, you understand the sentences making up this article, even though you have never encountered most of them before.

We can also appreciate the dependence of philosophy on language by considering how humans do philosophy. When we talk about what past philosophers achieved, we are talking almost entirely about what they achieved in their writings. Although Socrates famously did not write philosophy, he did it in conversation instead. In all these cases, what they achieved was achieved in language. Some philosophy books also have diagrams, or pictures, or logic formulas, which may be important to the book’s overall argument, but their philosophical significance still depends on the surrounding text. Anyway, languageless animals do not use diagrams, or pictures, or logic formulas. A few contemporary philosophers claim to have made contributions to philosophy in the form of dance, but again it is hard to see how a dance could have philosophical significance except in ways which depend on an associated verbal discourse.

A more radical challenge might come from a mystic, who claims to have had a languageless experience of reality which constitutes a great philosophical insight. If the experience inspires a philosophical book, we can judge the book rather than the experience. But a hard-line mystic might claim that the languageless experience itself, not anything it inspired, is the real philosophical achievement. Maybe cats, dogs, pigs, or owls have had similar languageless experiences.

One problem with the mystic’s claim is that philosophy is not a private enterprise. It is carried on from generation to generation of philosophers, teachers and students, authors and readers, working together in communities, discussing and arguing with each other. An individual’s experience, as opposed to a verbal description of it, cannot be passed down from generation to generation. What might be passed on is a recipe for having an experience of that type, by taking drugs, or practising meditation techniques, or whatever. But that leaves another problem. If it is claimed to be a languageless experience of reality, is reality indeed the way the experience presents it as being? Even if anyone who has an experience of that type is utterly convinced at the time that reality is that way, that does not mean that the conviction is infallible; the drugs or meditation techniques might just be a way of inducing a convincing hallucination. The more important the “insight” would be if right, the more important it is to test whether it is right.

Can words express how reality is mystically experienced as being? If they can, we have claims in words which need to be tested. But if we are told that words cannot express how reality is mystically experienced as being, and that the only way of testing the great insight is by having the experience oneself, we should start to suspect a scam. If an insight is genuinely important, it is so because it has lots of significant consequences, which make some sort of difference and so can be independently tested. If we are allowed no way to question the veracity of the mystical experience, we are falling victim to some kind of intellectual authoritarianism, quite alien to the traditional spirit of philosophy.

Alternatively, mystics might avoid the claim that the mystical experience is of reality, and say that it is just a great experience. If they add that having the experience is good for your mental health, that claim too should be tested. However, they might just say that having the experience is good in itself, irrespective of consequences. Fine; but how is having a great experience supposed to be relevant to philosophy? It would be relevant if philosophy were just a matter of having a good time, in a spiritual sort of way, but that is an utterly impoverished and self-indulgent conception of philosophy.

As it has more traditionally been understood, philosophy is an attempt to answer very general questions about the nature and structure of reality (which includes the attempt itself), about how things are (which includes how they appear). Because the attempt is serious, answers given to those questions cannot simply be taken on trust; no guru has the last word. They must be tested seriously by other philosophers, against any relevant evidence. The strengths and weaknesses of alternative answers must be identified, discussed, and compared. Once philosophy is understood that way, it is obviously out of reach for creatures with no well-developed language for communication.

None of this means that philosophy must be about language. Its medium is language, extended by diagrams, pictures, formulas, and so on, but physics has more or less the same medium, yet physics is not about language. Philosophy is about reality much more generally, of which language is just a small part. But since philosophy is mainly done in language, philosophers have to be careful and critical in their use of language, otherwise they may be misled by its subtle complications. In ordinary language, valid arguments and invalid arguments can easily look very like each other; sometimes we can tell them apart only by analysing the fine structure of our premises and conclusions.

That account may sound far from the natural beginning of philosophy in curiosity and common sense. But once we express our curiosity by asking questions in common language, and try to answer them by the methods of common sense, including critical discussion, iterating that process can gradually refine what we are doing, taking us towards the most sophisticated methods of philosophy.

This is an edited version of the discussion that followed a recent lecture by Timothy Williamson at Peking University. A recording of the lecture is available here.

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Sebastian Sunday-Grève is a German philosopher, who was educated at Oxford and is living in Beijing, where he works as an assistant professor at Peking University. He is a member of the Chinese Institute of Foreign Philosophy and, in 2020–21, a Fellow of the Berggruen China Research Center, where he works on the philosophy of artificial intelligence.

Timothy Williamson is the Wykeham Professor of Logic at the University of Oxford and a Visiting Professor at Yale. His recent books include Philosophical Method: A Very Short Introduction (Oxford, 2020) and an enlarged edition of The Philosophy of Philosophy (Wiley, 2021). In addition to logic, he works on epistemology, metaphysics and the philosophy of language.