Ludwig Wittgenstein is regarded by many, including myself, as the greatest philosopher of this century. His two great works, Tractatus Logico-Philosophicus (1921) and Philosophical Investigations (published posthumously in 1953) have done much to shape subsequent developments in philosophy, especially in the analytic tradition. His charismatic personality has fascinated artists, playwrights, poets, novelists, musicians and even movie-makers, so that his fame has spread far beyond the confines of academic life.

And yet in a sense Wittgenstein’s thought has made very little impression on the intellectual life of this century. As he himself realised, his style of thinking is at odds with the style that dominates our present era. His work is opposed, as he once put it, to “the spirit which informs the vast stream of European and American civilisation in which all of us stand.” Nearly 50 years after his death, we can see, more clearly than ever, that the feeling that he was swimming against the tide was justified. If we wanted a label to describe this tide, we might call it “scientism,” the view that every intelligible question has either a scientific solution or no solution at all. It is against this view that Wittgenstein set his face.

Scientism takes many forms. In the humanities, it takes the form of pretending that philosophy, literature, history, music and art can be studied as if they were sciences, with “researchers” compelled to spell out their “methodologies”—a pretence which has led to huge quantities of bad academic writing, characterised by bogus theorising, spurious specialisation and the development of pseudo-technical vocabularies. Wittgenstein would have looked upon these developments and wept.

There are many questions to which we do not have scientific answers, not because they are deep, impenetrable mysteries, but simply because they are not scientific questions. These include questions about love, art, history, culture, music-all questions, in fact, that relate to the attempt to understand ourselves better. There is a widespread feeling today that the great scandal of our times is that we lack a scientific theory of consciousness. And so there is a great interdisciplinary effort, involving physicists, computer scientists, cognitive psychologists and philosophers, to come up with tenable scientific answers to the questions: what is consciousness? What is the self? One of the leading competitors in this crowded field is the theory advanced by the mathematician Roger Penrose, that a stream of consciousness is an orchestrated sequence of quantum physical events taking place in the brain. Penrose’s theory is that a moment of consciousness is produced by a sub-protein in the brain called a tubulin. The theory is, on Penrose’s own admission, speculative, and it strikes many as being bizarrely implausible. But suppose we discovered that Penrose’s theory was correct, would we, as a result, understand ourselves any better? Is a scientific theory the only kind of understanding?

Well, you might ask, what other kind is there? Wittgenstein’s answer to that, I think, is his greatest, and most neglected, achievement. Although Wittgenstein’s thought underwent changes between his early and his later work, his opposition to scientism was constant. Philosophy, he writes, “is not a theory but an activity.” It strives, not after scientific truth, but after conceptual clarity. In the Tractatus, this clarity is achieved through a correct understanding of the logical form of language, which, once achieved, was destined to remain inexpressible, leading Wittgenstein to compare his own philosophical propositions with a ladder, which is thrown away once it has been used to climb up on.

In his later work, Wittgenstein abandoned the idea of logical form and with it the notion of ineffable truths. The difference between science and philosophy, he now believed, is between two distinct forms of understanding: the theoretical and the non-theoretical. Scientific understanding is given through the construction and testing of hypotheses and theories; philosophical understanding, on the other hand, is resolutely non-theoretical. What we are after in philosophy is “the understanding that consists in seeing connections.”

Non-theoretical understanding is the kind of understanding we have when we say that we understand a poem, a piece of music, a person or even a sentence. Take the case of a child learning her native language. When she begins to understand what is said to her, is it because she has formulated a theory? We can say that if we like—and many linguists and psychologists have said just that—but it is a misleading way of describing what is going on. The criterion we use for saying that a child understands what is said to her is that she behaves appropriately-she shows that she understands the phrase “put this piece of paper in the bin,” for example, by obeying the instruction.

Another example close to Wittgenstein’s heart is that of understanding music. How does one demonstrate an understanding of a piece of music? Well, perhaps by playing it expressively, or by using the right sort of metaphors to describe it. And how does one explain what “expressive playing” is? What is needed, Wittgenstein says, is “a culture”: “If someone is brought up in a particular culture-and then reacts to music in such-and-such a way, you can teach him the use of the phrase ‘expressive playing.’” What is required for this kind of understanding is a form of life, a set of communally shared practices, together with the ability to hear and see the connections made by the practitioners of this form of life.

What is true of music is also true of ordinary language. “Understanding a sentence,” Wittgenstein says in Philosophical Investigations, “is more akin to understanding a theme in music than one may think.” Understanding a sentence, too, requires participation in the form of life, the “language-game,” to which it belongs. The reason computers have no understanding of the sentences they process is not that they lack sufficient neuronal complexity, but that they are not, and cannot be, participants in the culture to which the sentences belong. A sentence does not acquire meaning through the correlation, one to one, of its words with objects in the world; it acquires meaning through the use that is made of it in the communal life of human beings.

All this may sound trivially true. Wittgenstein himself described his work as a “synopsis of trivialities.” But when we are thinking philosophically we are apt to forget these trivialities and thus end up in confusion, imagining, for example, that we will understand ourselves better if we study the quantum behaviour of the sub-atomic particles inside our brains, a belief analogous to the conviction that a study of acoustics will help us understand Beethoven’s music. Why do we need reminding of trivialities? Because we are bewitched into thinking that if we lack a scientific theory of something, we lack any understanding of it.

One of the crucial differences between the method of science and the non-theoretical understanding that is exemplified in music, art, philosophy and ordinary life, is that science aims at a level of generality which necessarily eludes these other forms of understanding. This is why the understanding of people can never be a science. To understand a person is to be able to tell, for example, whether he means what he says or not, whether his expressions of feeling are genuine or feigned. And how does one acquire this sort of understanding? Wittgenstein raises this question at the end of Philosophical Investigations. “Is there,” he asks, “such a thing as ‘expert judgment’ about the genuineness of expressions of feeling?” Yes, he answers, there is.

But the evidence upon which such expert judgments about people are based is “imponderable,” resistant to the general formulation characteristic of science. “Imponderable evidence,” Wittgenstein writes, “includes subtleties of glance, of gesture, of tone. I may recognise a genuine loving look, distinguish it from a pretended one… But I may be quite incapable of describing the difference… If I were a very talented painter I might conceivably represent the genuine and simulated glance in pictures.”

But the fact that we are dealing with imponderables should not mislead us into believing that all claims to understand people are spurious. When Wittgenstein was once discussing his favourite novel, The Brothers Karamazov, with Maurice Drury, Drury said that he found the character of Father Zossima impressive. Of Zossima, Dostoevsky writes: “It was said that… he had absorbed so many secrets, sorrows, and avowals into his soul that in the end he had acquired so fine a perception that he could tell at the first glance from the face of a stranger what he had come for, what he wanted and what kind of torment racked his conscience.” “Yes,” said Wittgenstein, “there really have been people like that, who could see directly into the souls of other people and advise them.”

“An inner process stands in need of outward criteria,” runs one of the most often quoted aphorisms of Philosophical Investigations. It is less often realised what emphasis Wittgenstein placed on the need for sensitive perception of those “outward criteria” in all their imponderability. And where does one find such acute sensitivity? Not, typically, in the works of psychologists, but in those of the great artists, musicians and novelists. “People nowadays,” Wittgenstein writes in Culture and Value, “think that scientists exist to instruct them, poets, musicians, etc. to give them pleasure. The idea that these have something to teach them-that does not occur to them.”

At a time like this, when the humanities are institutionally obliged to pretend to be sciences, we need more than ever the lessons about understanding that Wittgenstein—and the arts—have to teach us.