[Rethinking Philosophy] Rereading Wittgenstein: (4) Toward the Problem of Certainty

Abstract:
Addressing his final work, 'On Certainty,' this article examines 'certainty' as the non-questioning ground that allows doubt itself to exist. Certainty is not a property of propositions, but an attitude presupposed in action, acting as a 'riverbed' that performs the same function as the 'silence' discussed throughout this series. By demonstrating that solipsism, silence, and certainty are different expressions of the same structure, I present a perspective that views the world as the very movement in which two phases alternate.

Introduction: Why arrive at 'certainty'?

Over the past three articles, this series has reconstructed Wittgenstein's thought from the perspectives of solipsism, silence, and private language. In the first article, I reread the 'Tractatus Logico-Philosophicus' as the extreme of solipsism, confirming that silence can be understood not as a theoretical defeat, but as an ethical attitude toward speaking. In the second article, I reinterpreted the transition from the middle to the later period not as an evolution of theory, but as a shift in positioning from observer to practitioner. In the third article, I redefined the private language problem in 'Philosophical Investigations' not as a denial of possibility, but as a divergence between the two phases of observation and practice.

The arguments accumulated thus far converge on a single point.
That is the question: at what point do we stand before speaking, doubting, or assigning meaning can even take place? The argument of this article is clear. The discussions in the previous three articles did not arrive at a similar composition by chance; they were led by logical necessity to a point isomorphic to the problem setting in 'On Certainty.' This coincidence is not merely a similarity. It is simply the same structure being expressed in a different way.

1. Outside of Skepticism—Reframing the Problem

In 'On Certainty,' Wittgenstein is not tackling the traditional epistemological question of what is true or what can be proven. Rather, he is asking under what conditions the act of doubting itself is established. The goal is not to refute skepticism, but to clarify the premises that make skepticism possible.

What is important here is that when he states, 'In order to doubt, there must be something that is not doubted,' this is not merely a point about psychological facts. If one tries to doubt everything, the act of doubting itself spins in a vacuum. In other words, doubt cannot expand without limit; it always relies on some non-questioning ground. This ground is not reached through doubt. Rather, it is something already accepted before doubt can even be established.

2. Certainty as a Riverbed—The Unspoken Premise

Wittgenstein expresses this relationship through the metaphor of the flow of propositions and the riverbed that supports them. Propositions flow, are doubted, and are verified, but that movement can only occur on a stable foundation. This foundation is usually not conscious, nor is it verbalized, but without it, no meaning can be established.

What is decisive here is that this riverbed should not be grasped as a type of knowledge. It is not something that is 'known for certain,' but something that is 'already being done'—that is, an attitude presupposed in action. In other words, certainty is not a property of propositions, but a prerequisite for propositions to exist.

This structure matches what I have treated as 'silence' in the previous three articles. Silence is not a realm that cannot be spoken of, but a limiting condition that allows speaking to occur, and at the same time, it is a premise. It is not meaningless because it is unspoken; it is unspoken precisely because it supports the meaning of what is spoken. In this sense, it can be said that silence and the riverbed perform the same function.

3. The Position of Private Language—Invalidating the Question

When we re-examine the private language problem from this point, its meaning changes significantly. It is generally explained that private language is impossible because it lacks a public standard to verify whether it follows rules. However, this explanation presupposes that one is already standing in the phase of practice.

In reality, the problem is not whether private language is possible or impossible. The problem is at what point that question is established. The moment we enter the field where language is used, rules are applied, and correctness becomes an issue, language is inevitably incorporated into a shared structure. At that point, private language cannot exist. However, before entering such a field—that is, as long as one remains in the phase of observation—private language is at a point where it can be said to be neither established nor impossible.

What 'On Certainty' reveals is precisely this 'point where the question is not established.' We do not usually claim to 'know' that we have hands here. This is not because there is no room for doubt, but because the language game of doubting is not open in the first place. At this point, the distinction between knowledge and doubt has not yet been established. Certainty belongs to a layer before this distinction arises.

4. The Displacement of Solipsism—From Proposition to Attitude

This structure applies equally to solipsism. Solipsism is generally understood as the claim that the world is reduced to my consciousness, but what I have clarified in this series is that it is rather an attitude regarding how one relates to the world. The fact that the world appears as my experience cannot be denied, but the moment one tries to assert this as a universal proposition, solipsism loses its meaning.

When entering the field of practice, language functions within a shared context with others, and the world necessarily appears as something shared. At this time, solipsism does not hold. However, in the phase of observation, as long as one receives the world as one's own experience, solipsism persists as a valid attitude. In this sense, solipsism is displaced from a theory whose truth or falsehood is questioned to a matter of attitude regarding how one accepts the world.

Certainty is the same. It is not a collection of correct knowledge, but an attitude accepted in advance to allow doubt to exist. Here, it becomes clear that solipsism, silence, and certainty are different expressions of the same structure.

5. Conclusion: Certainty as the Ground Supporting the Reciprocation

Based on the above discussion, Wittgenstein's thought should be understood not as a movement of denying and overcoming something as it progresses from the early to the later period and finally to his last years, but as a movement of re-grasping the same structure from different positions. In the early period, silence is accepted as an observer; in the later period, the interior of language games is described as a practitioner; and in his final years, the ground itself that supports both is problematized.

What is important here is that we are not fixed in any one of these positions. We are constantly moving back and forth between the phase of observation, where we receive the world in silence, and the phase of practice, where we engage with the world within language. And what makes this movement possible is the layer of certainty that is unspoken, unquestioned, yet always presupposed.

Therefore, 'On Certainty' is not an addendum added from the outside to the arguments of the previous three articles. It is rather the inevitable conclusion that appears when one pursues the problems of solipsism, silence, and private language to their end. The world is neither solipsistic nor shared; it appears as the movement in which those two phases alternate. And certainty is nothing other than the invisible ground that supports that very movement.

See also: