Considered by many to be one of the leading philosophers of the 20th century, Austrian- British Ludwig Wittgenstein (1889–1951), had a major influence on logic, logical positivism, as well as on the philosophy of mathematics, mind, and language.

P.M.S. Hacker is currently Emeritus Research Fellow at Oxford University’s St. John’s College, where he had been a fellow from 1966 to 2006.

Dr. Peter Hacker is one of the most notable authorities on Wittgenstein and a distinguished historian of the analytic tradition. He is the author of the four-volume Analytical Commentary on the Philosophical Investigations, the first two volumes co-authored with G. P. Baker (Blackwell, 1980-96) and of Wittgenstein’s Place in Twentieth-Century Analytic Philosophy (Wiley-Blackwell, 1996). He has also written and lectured extensively on the philosophy of language and the philosophy of mind, as well as the relationship between philosophy and neuroscience. His most recently published books include Philosophical Foundations of Neuroscience (Wiley-Blackwell, 2003), and History of Cognitive Neuroscience (Wiley-Blackwell, 2008), both co-authored with M. R. Bennett, and Human Nature: The Categorial Framework (Wiley-Blackwell, 2007).

Simply Charly: Although Ludwig Wittgenstein came from a fabulously wealthy Viennese family with wide cultural interests and privileges, not all was rosy for the Wittgenstein clan. Can you describe some of the peculiar circumstances of some of the siblings?

Peter Hacker: Ludwig Wittgenstein was born in 1889 into an haute bourgeois Viennese family. His father Karl Wittgenstein was in effect the Carnegie of the Austrian steel industry. Ludwig was the youngest of eight children, with four brothers and three sisters. He was educated at home by a series of private tutors until the age of fourteen. Then he was sent to school at the Linz Realschule before going to the Technische Hochschule in Berlin-Charlottenburg to study engineering. Having graduated with a diploma in engineering in 1908, Wittgenstein went to Manchester to study aeronautics. It was while he was there that he first became seriously interested in philosophy. In 1911/12 he went to Cambridge to study philosophy with Bertrand Russell.

Tragedy had struck the family earlier when in 1902 and 1904 his two elder brothers committed suicide. They had been brought up to follow in their father’s footsteps as barons of industry. Both rebelled against this imposed career, ran away from home, and ultimately broke down in despair. The father after that avoided pressuring the remaining sons Kurt, Paul, and Ludwig. Paul displayed great musical gifts and had made a successful debut as a concert pianist when war broke out in 1914. While fighting on the Russian front that year, Paul lost his right arm. Despite this, he taught himself to play with his left hand alone, commissioning pieces from leading composers such as Ravel, Prokofiev, Britten, and others, and became a well-known pianist and music teacher.  In 1918, when the Austrian army on the Italian front collapsed, Kurt, who was a cavalry officer, committed suicide when his unit refused to continue fighting.

I do not know if there is any record of young Ludwig’s reactions to this succession of family tragedies. Certainly, he feared the temptations of suicide throughout his adult life.

SC: Wittgenstein’s Jewish background remained a constant source of conflict throughout his life, even though he declared he was “not a religious man.” Can you sketch the source of this pain in Wittgenstein?

PH: Wittgenstein did not have a Jewish background. He was of Jewish ancestry, for three of his four grandparents were Jews who had converted to Christianity. He knew virtually nothing about Judaism and was not at all attracted to it. In so far as he was, at various periods in his life, attracted by religion, it was primarily to a Tolstoyan form of Christianity.

That he was of Jewish ancestry was problematic to him, because he was brought up in Vienna—a seething cauldron of vicious antisemitism. He was intensely disturbed in the 1930s that he had let people believe that he was not of Jewish ancestry—and he confessed this guilt to some of his friends.

In some notes he wrote in 1931, he displayed some highly distasteful stereotypical conceptions of Jews. One can but hope that he came to see how foolish and contemptible such views are.

SC: Wittgenstein came to Cambridge University in 1912 to study with Bertrand Russell on the recommendations of the German mathematician Gottlob Frege. During this period, Wittgenstein often engaged in spirited conversation with Russell on many philosophical topics. Can you briefly describe their relationship?

PH: Their relationship went through various phases—first of pupil to great teacher, then of friends talking as equals, and then, as the relationship between them cooled, of friendly professional colleagues, until finally, the friendship died, and Wittgenstein moved intellectually beyond Russell’s comprehension.

When Wittgenstein arrived in Cambridge in 1911, he knew next to nothing about philosophy. He had read some Schopenhauer as a teenager. He had evidently read Russell’s Principles of Mathematics and some of Frege’s writings. He knew about the paradox that Russell had found in Frege’s system of axiomatized logic in 1903. His primary interest was in the nature of logic and logical necessity, the relationship between logic and language, and the relationship between language and the reality that it can depict. Within six months of young Wittgenstein’s arrival in Cambridge, the two were talking about the problems of logic as equals, and Russell was grooming Wittgenstein as his successor. In 1912, Russell said to Wittgenstein’s sister Hermine that he expected Wittgenstein to take the ‘next big step in philosophy.’ Within a year or so, Wittgenstein was dismantling Russell’s own views. His criticisms of Russell’s 1913 manuscript, Theory of Knowledge, so devastated Russell that he abandoned the project, and it was published in its entirety only in 1984, after his death. The rift between them arose, it seems when the young Wittgenstein objected to Russell’s moral views and attitude to life. They patched things up and resolved to restrict their relationship to professional matters of logic alone. Russell was instrumental, after the war, in getting Wittgenstein’s first masterpiece, the Tractatus, published. After that, the relationship between them became fairly remote, and although Russell supported Wittgenstein’s appointment to a Fellowship at Trinity in 1930, it became clear that he could not understand Wittgenstein’s later philosophy.

SC: While at Cambridge, Wittgenstein also developed an enduring relationship with Russell’s colleague, G. E. Moore. What was their relationship like?

PH: They seem to have enjoyed each other’s company and to have liked talking to each other—sufficiently so for Wittgenstein to have invited Moore to visit him in his retreat in Norway in 1913, where he dictated to Moore an important résumé of his ideas on what can and cannot be said in language. The relationship was broken by a foolish altercation originating with Wittgenstein and was not resumed until 1930. From that point forward, they remained on a friendly basis until Wittgenstein’s death. He esteemed Moore for his intellectual honesty and lack of vanity but did not think very highly of his intellectual powers.

SC: While serving on the eastern front in the First World War, Wittgenstein arrived at his picture theory of language, which formed the basis of his only work published during his lifetime, the Tractatus Logico-Philosophicus. What was Wittgenstein’s chief aim in this work?

PH: His aim was simple—to solve the problems of philosophy—or, at any rate, the chief and deepest problems of philosophy! Wittgenstein was never anything less than bold in his ambitions.

Put less dramatically, the central problems of the Tractatus were: first, to clarify the a priori conditions of symbolic representation in general. Secondly, to make clear the essential nature of symbolic representation, to explain how it is possible for signs to represent how things are. Thirdly, to explain how it is possible for a proposition to be false. For if a proposition is true, then what it represents is how things are; but if it is false, then what it represents doesn’t exist; yet what it represents is the same, no matter whether it is true or false. But how can that be, given that in one case it represents how things are and in the other case it doesn’t? This is the problem of the intentionality of the proposition, for which the solution of the picture theory of the proposition was devised. Fourthly, what is the nature of the truths of logic, and what explains their necessity? Fifthly, what are the limits of propositional representation? Are there truths that cannot in principle be represented? Hence, sixthly, what is the status of the propositions of metaphysics that purport to describe how things necessarily are in reality? And finally, what is the status of philosophy itself?

SC: Can you cite a couple of examples of how Wittgenstein dissolved some of philosophy’s perennial problems through the methods contained in his Tractatus?

PH: The question is a little misleading and somewhat anachronistic. When he wrote the Tractatus, Wittgenstein did not think of himself as dissolving philosophical problems. That conception belongs to his later philosophy, after the revolution in his thought that occurred in 1929-31. In the Tractatus, he conceived of himself as solving problems and answering questions, rather than as showing that the questions need to be deconstructed. Moreover, although Wittgenstein delineated a method for future philosophy, that method is barely practiced in the book at all. It was exhibited only once, in a paper he wrote in 1929, on his return to philosophy after a decade in the wilderness. This paper, entitled “Some Remarks on Logical Form” applied his envisaged method of analysis, and was almost immediately repudiated by its author in favor of his new philosophy, and its quite different methods.

Nevertheless, I’ll try to briefly explain Wittgenstein’s solution of a great problem of philosophy in the Tractatus. Propositions of logic had for centuries, puzzled philosophers. They appear to be necessary truths—that is, to be true come what may. They seemed to be known independently of any empirical evidence—by reason alone. They are certain, timeless, and irrefragable—boundary stones set in eternal foundations which our thought may overflow but never displace—as Frege wrote. Indeed, Frege held that such truths describe timeless relationships between propositions. Russell held that propositions of logic were the most general truths about the universe, concerning perfectly general relationships between properties, relations, and facts. Wittgenstein showed that they were both mistaken. The necessary truths of logic are not about anything. They are not generalizations at all (‘Either it is raining or it is not raining’ tells you nothing about the weather and is not a general truth at all; but it is a truth of logic). Rather, they are limiting cases of propositions with a sense. For although they are well-formed, they are so combined by truth-functional connectives that all content cancels out. They are necessary only because they exclude nothing. So they are senseless (not nonsense), have zero sense, as it were, and say nothing. Indeed, one might say, all logical truths say exactly the same, to wit—nothing. That is why logic is not a science with a subject matter, but a calculus. This insight was one of the great advances in 20^th-century philosophy of logic, and had a great impact on the Vienna Circle.

SC: It has been noted by some biographers that Wittgenstein’s outlook was significantly altered during the Great War. How so?

PH: Well, could anyone go through the frontline service in the Great War and not have his views of life changed? Wittgenstein went through some of the heaviest fighting on the Russian and Italian fronts, and was four times decorated for gallantry under fire. How could he not be a changed person?

I suppose that the major transformation in his way of life was in a broadly Tolstoyan direction. When he returned home from a prisoner of war camp in Casino in 1919, one of the first things he did was to divest himself of all his inherited wealth—which he transferred to his surviving siblings. He viewed his wealth as an encumbrance. He craved for a very simple life—pared down, as it were. Hence his endeavor to become a primary school teacher for peasant children in the mountains of Lower Austria, where he dressed simply, ate the simplest of foods, and lived off a pittance. This simplicity of lifestyle remained with him for the rest of his days.

SC: Moritz Schlick, a leading member of the Vienna Circle, greatly admired Wittgenstein’s work and had invited him to attend several of their meetings. To what extent was Wittgenstein involved with the Vienna Circle?

PH: Yes, Schlick thought the Tractatus was “the most significant philosophical work of our times” and that its new insights “are absolutely crucial to the destiny of philosophy.” He remarked that Wittgenstein was the greatest genius of all time in logic [i.e., the philosophy of logic]. The mathematician Hans Hahn, another founding member of the Circle, said “To me, the Tractatus has explained the role of logic.” And Rudolf Carnap later wrote “For me personally, Wittgenstein was perhaps the philosopher who, besides Russell and Frege, had the greatest influence on my thinking.” Jorge Jörgensen, in his semi-official history of the Circle, later wrote that Wittgenstein’s ideas “have on essential points determined the view of the Circle on philosophy and its relation to the special sciences.” So it is fair to say that Wittgenstein was the major inspiration for logical empiricism in the 1920s and 1930s and a major source of the ideas of the Circle.

In 1924 and again in 1926, the Tractatus was read and discussed line by line at the weekly meetings of the Circle. In 1927 Schlick actually met Wittgenstein and was overwhelmingly impressed by him. However, Wittgenstein refused to attend meetings of the Circle. Rather, he agreed to meet Schlick, his assistant Friedrich Waismann, Carnap, and Feigl for discussions, which, it seems, consisted largely in Wittgenstein’s talking, with occasional questions from his audience. Fortunately, we have some idea of these meetings, as Waismann recorded them in shorthand. Although Carnap and Feigl were later excluded, meetings with Schlick and especially with Waismann continued until the mid-30s. It was through these meetings and Waismann’s reports that Wittgenstein’s new ideas were transmitted to the Circle. They certainly had a greater influence upon the doctrines of logical empiricism than those of any other thinker—although sometimes through misunderstanding or incomprehension.

SC: In what respects were his ideas influential?

PH: I should distinguish five domains in which Wittgenstein’s ideas influenced the members of the Circle. First, they molded the Circle’s conception of philosophy as an exclusively elucidatory discipline. Its task, they held, is not to elaborate truths about the world or about all possible worlds, but to clarify the logic of the language of science. Secondly, they were fervent opponents of any form of metaphysics—and for this too, they found inspiration in the Tractatus, even though the anti-metaphysical line they took differed from Wittgenstein’s. Thirdly, they were all hugely impressed by Wittgenstein’s demonstration of the vacuity and tautological status of propositions of logic. It was this, they thought, that, for the first time, made consistent empiricism possible. Fourthly, the famous principle of verification, for which the Circle became so well-known, originated in remarks made by Wittgenstein. He toyed with this idea for about six months and then abandoned it. But the logical empiricists explored it for a couple of decades before finally rejecting it. Finally, the reductionism implicit in the Tractatus was undoubtedly a spur to the Circle’s conception of the unity of science.

SC: After a long absence, Wittgenstein returned to Cambridge University in 1929, where he began to rethink certain elements of the Tractatus. These reflections led him to a wholly different conception of how language works, which eventually formed the basis of his posthumously published masterpiece, Philosophical Investigations. In what important respects did this work differ from the Tractatus?

PH:  In very many respects indeed—enough for me to lecture to you now for the next seven or eight hours!  But that wouldn’t do at all.

Let me try to summarize the salient differences under five heads: stylistic; methodological; differences in goal; differences in ‘doctrine’; and the extension of interest into the domain of philosophy of psychology.

The stylistic character of these two masterpieces could hardly be greater. Both are great contributions to German letters. But the Tractatus is written in a marmoreal, sibylline style. Barely any examples illustrate the sublime doctrines being advanced, or sully their purity and generality.  It opens with the stark remarks: “The world is all that is the case . . . The world is the totality of facts, not of things. . . . The facts in logical space are the world.” Looking backwards to the great tradition of Western philosophy, it thunders: “Most of the propositions and questions to be found in philosophical works are not false but nonsense.” “Our life has no end in just the way in which our visual field has no limits,” and, like one of the prophetic books of the Old Testament, it proclaims: “The solution of the riddle of life in space and time lies outside space and time.” The book is dense with technical terminology, such as “pictorial form,” “representational form,” “logical form,” “method of projection,” “logical syntax,” “internal and external properties and relations,” “formal and material concepts,” “logical picture,” “bipolarity,” and so forth. Logical notation proliferates. By contrast, the Investigations is written in a relaxed, laid-back style of complete simplicity. There is virtually no technical terminology and no logical notation. Dozens of homely examples occur in the text. There are wonderful similes and metaphors: “Thought is surrounded by a halo”; “we feel as if we had to repair a torn spider’s web with our fingers”; “what we are destroying is nothing but houses of cards and we are clearing up the ground of language on which they stand”; “a main cause of philosophical disease—a one-sided diet: one nourishes one’s thinking with only one kind of example.” Most of the sentences of the Tractatus are difficult to understand. All of the sentences of the Investigations are straightforward—but what is opaque is why they are being said. That, incidentally, is quite deliberate. These stylistic differences are not incidental, but directly related to the goals, contents, and methods of the two books.

A second great difference lies in method. The Tractatus consists of pronouncements from the mountaintop. The Investigations consists of little conversations, sometimes between Wittgenstein and himself, sometimes between Wittgenstein and an imaginary interlocutor. Questions are more common than answers. Frequently, the trajectory of a thought is given, and the reader is left to follow it through. Very few overt pronouncements are made.

This reflects a deep shift, which, Wittgenstein once remarked in his notebooks, consists in the move from the method of truth to the method of sense. That, in turn, reflects a radical shift in Wittgenstein’s conception of philosophy. Philosophical problems arise out of unclarities about the sense or meaning of expressions, and they are to be resolved or dissolved thorough clarification of their meaning. Since the meaning of an expression is its use, the clarification of its meaning consists in highlighting one aspect or another of its familiar use. Which aspect of use needs to be highlighted depends on the specific confusion at hand. Another method whereby to illuminate the nature of the problematic concept is the method of describing language games. A language game is a partly rule-governed activity of using an expression in a context of human practices. Such language games may be actual, they may be prototypical primitive language games that serve to remind us how a concept might be introduced in a simpler form and context, or they may be wholly imaginary language games that illuminate by way of contrast. A third novel method is the extensive employment of reductio ad absurdum arguments—that is, not what logicians and mathematicians call by this name (what they are speaking of is strictly a reductio ad contradiction), but an argument that will show that a particular thought or idea results in transgressing the bounds of sense and talking literal nonsense.

This brings me to a third deep difference between the two books—a difference in goal. The Tractatus aimed, among other things, to describe the metaphysical structure of reality or, more accurately, to demonstrate how such structures are shown by features of the depth-grammar of any language or means of representation. By the time he came to write the Investigations, Wittgenstein had ceased to think that reality had a metaphysical structure (irrespective of whether it was effable or ineffable), and he did not think there was any such thing as depth-grammar. Grammar is all surface—but one has to look around and see the grammatical surround. The illusion of a metaphysical structure of reality is no more than the shadow thrown upon the world by the grammar of our language. Or to put it slightly differently, the metaphysical illusion of the scaffolding of the world is no more than the shadow cast by the grammatical scaffolding from which we describe the world.

Wittgenstein’s goal in the Investigations is Janus-faced. On the one hand, his goal is to describe the use of the problematic concept that is causing trouble, to locate it in the web of words, and to delineate its logical relations to other concepts. On the other, it is to dissolve philosophical puzzlement and confusion by showing where one goes off the high road of sense and wanders unaware into the jungles of nonsense.

The fourth class of differences is, so to say, “doctrinal.” Contrary to the Tractatus, Wittgenstein now argued that the meaning of an expression is its use, that the meaning of an expression is given by humdrum explanations of meaning, that predicates need not be sharply defined or satisfy the requirements of determinacy of sense, that analysis is not the only or even a major tool for conceptual elucidation. He denied that there is any such thing as the essence of a proposition or of a language, for the concepts of language and of a proposition are what he termed ‘family-resemblance concepts.’ He repudiated the ontology of the Tractatus and the metaphysics of symbolism of the picture theory.

Finally, the Tractatus contained no examination of psychological concepts or of the manner in which they are employed in first-, and in third-person cases. There are some important hints as to what he thought, but nothing worked out. By contrast, approximately half of the Investigations is concerned with the grammatical description of those psychological concepts that bear on questions about linguistic meaning. These include such concepts as understanding, meaning something by one’s words or deeds, knowledge of other minds, sensation, and perception, wanting and intending, thought and imagination, consciousness, and the “I.” This paves the way for Wittgenstein’s post-Investigations examination of psychological concepts, which comprises some 1900 pages, now printed in the form of four volumes.

SC: In the preface to the Investigations, Wittgenstein writes, “I have been forced to recognise grave mistakes in what I wrote in that first book.”  Do we know what these “grave mistakes” were?

PH: Oh yes. Let me select a few of the salient ones that he explicitly discusses in the Investigations. (I shall omit those discussed in his Remarks on the Foundations of Mathematics.)

His whole conception of language and linguistic representation in the Tractatus was awry. He thought then that a language is a calculus of meaning rules and primitive terms. In the Investigations, he realizes that a language is not a calculus but a rule-governed social practice partly constitutive of a human form of life or culture.

In the Tractatus, he thought, like Chomsky,  Davidson and many of our contemporaries did after him, that a language has a depth-grammar and hidden structure that remains to be revealed by logico-linguistic analysis. Later he came to think this an illusion. There is not, and could not be, a hidden depth-grammar. For grammar consists of rules, and there can be no following of unknown rules, and no tacit knowledge of rules awaiting discovery.

In the Tractatus, he thought that the essence of words is to name things, and the essence of propositions is to describe states of affairs. In the 1930s, he came to realize that relatively few words are definable by reference to necessary and sufficient conditions that specify the essence of what falls under them. The concepts of name and proposition are family-resemblance concepts, and names and propositions have no essence.

In the Tractatus, following Frege, he thought a language must—as a condition of sense—satisfy the requirement of determinacy of sense. For every proposition, it seemed, must be either determinately true or determinately false, otherwise, the laws of logic—in particular, the law of excluded middle that every proposition is either true or false—would not apply to it. So every concept-word must be sharply defined so that any possible object of which it can be predicated must either fall under it or not. So there can be no vagueness in language. All apparent vagueness must be a surface-grammatical phenomenon that will disappear on analysis. In the Investigations he came to realize that this is a chimerical idea—that many of our concepts are vague, and none the worse for that. “I asked him for a bread knife,” he mocked, “and he gives me a razor blade because it is sharper.”

In the Tractatus, he held that every well-formed proposition is a “logical picture” of a possible state of affairs, which is true if the state of affairs pictured obtains, and otherwise is false. In the Investigations, the picture theory is repudiated, and the problem of the intentionality of the proposition is shown to dissolve into triviality and platitude.

SC: What then are Wittgenstein’s main constructive contributions to philosophy in his later work?

PH: Well, it is difficult to summarize the thoughts of a great genius in a few remarks. But if you twist my arm, I should venture the following observations:

Wittgenstein worked mainly in three domains: philosophy of language, philosophy of mathematics, and philosophy of psychology. In each, he transformed the landscape—for those who had the wit to see. All his later work is informed by his revolutionary conception of philosophy, which is, in some ways, his most important legacy. But it is impossible to grasp his meta-philosophical reflections without first understanding his philosophical practice. I shall say a few words about Wittgenstein’s later philosophy of language and his philosophy of mind.

In his philosophy of language, he strove to overturn the conception of linguistic meaning and understanding that has dominated European thought since antiquity: namely, that the essential function of words is to stand for things—for objects, properties, and relations, and that the essential function of sentences, which are ordered combinations of names, is to describe how things stand. He also sought to overthrow the conception of a language as a calculus of meaning rules and primitive indefinables—as he himself had thought when he wrote the Tractatus, and as Russell had thought when he wrote Principia Mathematica. In place of all this, he delineated a quite different conception of language as an array of partly rule-governed activities integrated into a complex form of life and culture.

Mainstream tradition had conceived of language as a means by which we can communicate our thoughts to others. Thought itself, it was commonly supposed, is independent of language. This too Wittgenstein repudiated. The limits of possible thought are the limits of its possible expression. It makes sense to ascribe to a creature only such thoughts and thinking as could be expressed by the resources of its behavioral repertoire. That is why a dog may think it is now about to be taken for a walk (it has just heard its leash being taken down, and is barking excitedly), but cannot now think it is going to be taken for a walk tomorrow. For nothing short of linguistic behavior and a language involving devices for temporal reference could express such a thought. It is precisely because we are language-using creatures that the horizon of our thoughts is so vast.

Wittgenstein’s philosophy of psychology gave quietus to Cartesian dualism, to behaviorism, and by implication to the degenerate Cartesianism exhibited by contemporary cognitive science and cognitive neuroscience. The mind is not a spiritual substance—as the Cartesians supposed—but it is not a material substance (the brain) either since it is not a substance at all. In so far as it can be said to be anything, it is a set of intellectual capacities distinctive of language-using creatures. But better: For a creature to have a mind is for it to have and exercise an array of distinctive intellectual capacities of thought, memory, and rational will. Muddled talk of the relationship between mind and body is at best a mere façon de parler (expression) behind which is nothing other than reference to the distinctive capacities of a person and their exercise by that person.

Mainstream philosophy of psychology to this day is committed to the intelligibility of mastery of psychological concepts independently of mastery of their application to others. That is, it is commonly held that it makes sense to suppose that one can grasp the meaning of psychological verbs and their cognates and apply them to oneself, prior to being able to apply them to others. For the latter, many psychologists have argued, one needs to construct a theory of mind. This conception Wittgenstein definitively showed to be incoherent. Self-ascription of experience is possible only on condition of mastery of the concepts of experience, and mastery of these concepts requires a grasp of the grounds for their ascription to others. Such grounds consist of behavior, expression, and utterance. So the groundless ascription of predicates of sensation, perception, thought, emotion, and will to oneself presupposes one’s grasp of the behavioral grounds for their ascription to others.

I shall not say anything about his philosophy of mathematics, except to remark that it is the least understood part of his later philosophy, and that it is no less original and revolutionary than his other contributions to philosophy.

Now, a word or two about Wittgenstein’s later conception of philosophy. He did not think philosophy could contribute to our knowledge of the world, after the manner of the empirical sciences, let alone to our knowledge of all possible worlds (as today’s meta-physicists would have it), since there are no possible worlds, any more than there are possible people. He held that philosophy was a contribution to human understanding—in particular, to the understanding of the structure of our conceptual scheme. The task of philosophy is to resolve or dissolve philosophical problems. Philosophical problems are conceptual confusions. They arise through difficulties in finding our way around our own conceptual scheme. They can be dissolved only by scrutiny of the use of words, by a meticulous survey of the network of related concepts, and a demonstration that the bounds of sense have been transgressed.

Philosophy is not continuous with science. It is not even in the same business as science. And its results are not additions to the sum of our knowledge of the world. There is no room for theories in philosophy on the model of scientific theories that can be confirmed or infirmed in experience. There is no room for hypotheses, for it cannot be a hypothesis that a certain form of words makes sense. The task of philosophy is to achieve conceptual clarity—a perspicuous overview of a segment of our conceptual scheme, and thereby the resolution or dissolution of philosophical problems. The rewards of philosophy are conceptual clarity, and the ability to find our way around our conceptual scheme so that we can cope with conceptual confusions when they arise. Past philosophers searched for the map of Treasure Island in order to find the hidden treasures of metaphysical insights into the essence of the world. It took Wittgenstein to realize that the treasure is the map.

SC: To this day, Wittgenstein’s philosophy is still misunderstood and misinterpreted. No consensus exists among interpreters of Wittgenstein’s work. How would you advise one to begin a study of his philosophy? Are there particular works from the vast body of secondary sources you’d recommend beyond his original works?

PH: Wittgenstein is not an easy philosopher, and there is no way of making him so. One can help people climb the north face of the Eiger—but one cannot make it easy. The best general introduction to his thought of recent years is Severin Schroeder’s Wittgenstein: The Way out of the Fly-bottle (Polity Press, Cambridge, 2006). An excellent dictionary to be used for assistance while reading Wittgenstein’s works is H.-J. Glock’s A Wittgenstein Dictionary (Blackwell, Oxford, 1996). For a general overview of his philosophical achievement, and for the historical context and the impact of his work, I would like to recommend a book of mine: Wittgenstein’s Place in Twentieth Century Analytic Philosophy (Blackwell, Oxford, 1996).