Wittgenstein is famous for revolutionizing philosophy not once but twice. He claimed to have solved all the problems of philosophy in his Tractatus Logico-Philosophicus, only to return to philosophy ten years later, repudiate many of the central claims of the Tractatus, and reinvent philosophy a second time with the Philosophical Investigations. Among the central differences between the early Wittgenstein of the Tractatus and the later Wittgenstein of the Philosophical Investigations and his various notebook writings is a shift in emphasis regarding the importance of logic. In the Tractatus, logic is given central importance as determining the structure of language and reality, but it receives scarcely a mention in the Investigations. Wittgenstein’s later philosophy abandons the rigidly structured world of the Tractatus in favor of a less pristine and more modest conception of a complex world that resists any simple articulation. While the differences between the early and later philosophies of Wittgenstein go deep, significant similarities remain. The four themes that follow trace some of the most important points on which Wittgenstein’s position does not change radically throughout his career.

While Wittgenstein repeats that ordinary language is fine as it is, he also identifies the misuse of that language as the source of much philosophical confusion. Language is suited to its everyday business of facilitating communication between people. Philosophers make the mistake of abstracting language from its ordinary contexts to understand the essences of things. For example, when people talk about knowing things, in most contexts it is perfectly obvious what they mean. But despite the fact that we can talk about what we know without complication, we are puzzled when confronted by a question like, what is knowledge? All of a sudden, we are faced with an abstract concept, “knowledge,” divorced from the contexts in which this concept is used. When philosophers get confused over the question of what knowledge is, they are not confused because the essence of knowledge is difficult to identify. Rather, they are confused because they have abstracted a word from the contexts in which it has a function and find that, outside these contexts, the word loses its meaning. If philosophers were careful about how they use language, Wittgenstein believes, philosophical confusion would cease to exist.

The correct approach to philosophical problems, according to Wittgenstein, is not to attempt to solve them but rather to reach a point where the problems dissolve of their own accord. The problems of philosophy, in this view, are in fact pseudoproblems. Where we think we perceive a problem, we are in fact caught in philosophical confusion. For example, in On Certainty, Wittgenstein attempts to unravel the problem of external-world skepticism, showing that the very question of how we can know that there is a world external to our senses only arises if we misunderstand the nature of propositions, such as “here is a hand”—in actual life, such propositions are not offered as knowledge that might be proven true or false. Wittgenstein’s approach is not to say that external-world skepticism is false but rather to show that the very question of whether external-world skepticism is true or false arises out of a misunderstanding of the language we use. If we absorb Wittgenstein’s teachings, we do not come to settled solutions to the philosophical problems that haunt us, but rather we reach a state where these problems cease to haunt us. What Wittgenstein seeks is not solutions so much as an end to theorizing.

Wittgenstein emphasizes the difference between his philosophy and traditional philosophy by saying that his philosophy is an activity rather than a body of doctrine. We can identify definite positions and theories in the writings of most traditional philosophers but not with Wittgenstein. In fact, Wittgenstein’s writings are distinctly antitheoretical: he believes that the very idea of a philosophical theory is a sign of confusion. He conceives of the role of philosophy as an activity by which we unravel the sorts of confusion that manifest themselves in traditional philosophy. This activity carries with it no theories or doctrines but rather aims at reaching a point where theories and doctrines cease to confuse us. In the Philosophical Investigations, Wittgenstein writes, “the work of the philosopher consists in assembling reminders for a particular purpose.” That is, his ideal philosopher works to remind those confused by abstract theorizing of the ordinary uses of words and to set their thinking in order. The clarity achieved through this kind of activity is not the clarity of a coherent, all-encompassing system of thought but rather the clarity of being free from being too influenced by any systems or theories.

Wittgenstein scholars disagree as to whether his work ought to represent an end to philosophy. Certainly, his work has a conclusive feeling about it. In the preface to the Tractatus, he writes, “I am . . . of the opinion that the problems [of philosophy] have in essentials been finally solved.” If we wholeheartedly embrace his work, either the Tractatus or his later writings, we will no longer be able to speculate about the problems of philosophy as thinkers have done for the previous two and a half millennia. However, it is far from clear that Wittgenstein intends for all philosophical activity simply to cease. Rather, he seems to intend a new role for philosophy, as an activity of clarification.

While the main target of this activity seems to be traditional philosophy, it would presumably continue to have a role even if everyone were to give up traditional philosophy. So long as we continue to think, we are liable to fall into intellectual confusion. While philosophy is a particularly rich source of intellectual confusion, no field of thought is free from confusion. In his later writings, Wittgenstein devotes a great deal of energy to picking apart the confusion inherent in the nascent field of experimental psychology. We might conclude that Wittgenstein does not want to do away with philosophy so much as he wants to reinvent it.