Skepticism and logical possibility

While skepticism takes many different forms, the primary form of skepticism under consideration can be described by single, general argument. This skepticism’s basic premise is that we are unable to logically disprove possible states of affairs in the world that would undermine our claims to knowledge about reality (“skeptical possibilities”). Generally, arguments for skepticism, including the original Cartesian skepticism formulation, ultimately take the form of a modus ponens argument, such as,

1. If I can not distinguish between dreaming and being awake, then I can not be sure I have a body.
2. I can not distinguish between dreaming and being awake.
3. Therefore, I can not be sure that I have a body.

Support for the second premise derives from the possibility that, for any empirical proposition we form at a point in time, events could follow that would provide evidence to falsify that belief. If this is true, no empirical proposition is verifiable and thus none are certain.

Wittgenstein does not disagree with this, to an extent; he grants that such subsequent falsifying events are indeed always a possibility. For example, one may have very good reasons for believing his old friend is standing in front of him, but it is imaginable for that person to suddenly start behaving as though he was not that old friend after all (613).[1] However, Wittgenstein challenges the notion that such events transpiring would undermine the relevant prior empirical beliefs about the situation. In other words, he argues that such possibilities do not undermine “knowledge,” in the meaningful sense of the word, but merely fail to satisfy the conditions of a notion of logic removed from practitioners of logic (human beings).

Wittgenstein on doubt

In the second paragraph of On Certainty, Wittgenstein elucidates the role of doubt, almost spelling out immediately what will become his objection against skepticism: “from its seeming to me – or to everyone – to be so, it doesn’t follow that it is so. What we can ask is whether it can make sense to doubt it [emphasis added]” (2). Though the skeptics are correct in questioning the assertion of seeming or “common-sense” empirical fact, such doubts fail to (meaningfully) endorse their assertion that all knowledge can be undermined. Hence, Wittgenstein attacks the core of “radical doubt” as non-sensical.

Primarily, the skeptics make the error of conceiving logic as an empirical statement – as something independent of the agent in question – that is subject to the possibility of falsification. The Tractatus, though earlier in Wittgenstein’s philosophical development, is particularly illustrative of this problem with skepticism: “Propositions cannot represent logical form: it is mirrored in them. What finds reflection in language, language cannot represent.”[2] Moreover, we cannot sensibly falsify (or take any other action standing outside of) logic, since we can not describe what a non-logical world would look like.[3] Yet this is precisely what skepticism demands.

Skepticism, by externalizing logic, thus encounters serious error when it casts extreme doubts upon common-sense propositions, which are necessary for establishing language (and hence the use of logic). When someone says, “There are trees,” he is presupposing the existence of objects. This is not to imply an epistemological assertion that there are objects in a specific sense of the word, but it simply reveals the absurdity of saying “objects do not exist.” If one holds that to be true, he runs into the intractable problem of explaining of what it is that one is speaking when one says “there are trees.” Day to day life demonstrates that common-sense propositions must be known in some way, as evidenced by the fact that we say things to others like “move that table over here” or “open the window” (7). In light of this, the nature of being mistaken about a statement like, “I am certain that these are words on this paper” is unclear (17, 24, 32). What it would be like to find out that “here is not a hand” is peculiar and seemingly indescribable by language. This is because the language-games people use, those ingrained deeply in their practices and beliefs, depend on affirming such propositions in order for them to make any sense (to be explained shortly).

Furthermore, as Wittgenstein asserts several times, the notion of doubt presupposes certainty (115 and elsewhere). In order for one to doubt anything, one must first have certainty about what he doubts, be certain that he, in fact, doubts it, and so on. This relates closely to the foundation of (the human expression of) logic in language, as implied in Tractatus. In Philosophical Investigations, Wittgenstein delves into the nature of language games, which later play an important role in On Certainty. Section 7 of Investigations states, “I shall call it the whole, consisting of the language and the actions into which it is woven, the language-game.”

Learning and language

 Wittgenstein explores how a child learns and the relationship between its learning and language in section 6 of the Investigations. A child learns what words mean by ostensive action; for example, one might instruct, “that is a chair; that is a car; that is red; etc.” In all this, however, there is a necessity for an understanding of ostensive definition itself. A child, to learn that “this is called ‘car’,” must first comprehend that names can be assigned to things. Later, in section 31, Wittgenstein uses an example of teaching someone how to play chess. When he points to a piece and says, “this is the king; it can move like this,…” the phrase “this is called the ‘king’” is only a definition if the student knows what a game is, what a piece in a game is, etc.

The point of the exploration of language games is, in short, that understanding requires some background of trust – some kind of sureness. Continuing in On Certainty with the case of the child, Wittgenstein says, “the child learns by believing the adult. Doubt comes after belief” (160). A child could never learn anything if he constantly questioned existence, for if that were to happen, he could never learn the definitions of things ostensively, just as if a person were to question the game or the pieces of chess, he would never learn that “this is called “the king” and it moves like so.”

The process of learning language is one of action (or reaction) first, then epistemological reflection at a later time once a system of beliefs is formed and it becomes gradually understood where doubt can be reasonable (538). For example, a child initially listens to verbal and written instructions, responding trustingly and candidly to what others say. When a child realizes that people have the capability to lie, however, he then has a reasonable basis for sometimes doubting the truth of what someone says. The system of belief he develops is essential to forming these kinds of curiosities and doubts. If he did not understand that other human beings like himself existed and behaved autonomously and with similar capabilities, he could not even begin to comprehend the notion of doubting the truth of their words. Moreover, even when he believed and spoke candidly, he would not have been able to do so had he questioned the existence of other human beings, and he would have not been able to understand the existence of other human beings if he questioned the existence of a world external to him.

Language is inextricably embedded into our lives. Without it, we would be unable to learn, and without learning, we would be unable to doubt. Further, it is the common understanding and foundations of language that allow human beings to communicate. Incidentally, by no means is the plain use of signs universally indicative of meaning (another basic idea explored in Tractatus that blocks a potential route for skepticism). A person who interprets and acts upon the mathematical directive “halve” by multiplying by three hundred is not casting doubt upon halving, but is merely out of sync with the rules and norms of a language-game. He is not presenting a skeptical challenge to knowledge of mathematics.

At the crux of his argument, Wittgenstein rejects the Cartesian-style premise that all propositions, even foundational ones, should be doubted along with any beliefs that they justify, unless they can be proven empirically. The skeptics’ doubt of these propositions does not merely test the truth, falsehood, or likelihood of those propositions, but ultimately necessitates questioning the methods by which testable empirical propositions are tested (317, 318). If all knowledge is based on testable empirical propositions that are justified by methods that are themselves subject to the skeptics’ pervasive doubt, then one must always acknowledge skeptical possibilities (i.e., the skeptics’ position is meaningful).

 Skepticism of the external world isn’t useful

To counter this, Wittgenstein explains that claims like “here is a hand” or “the world has existed for longer than five minutes” merely appear to be statements about the external world that are true or false. However, these propositions lie beyond knowledge or doubt, because they serve as the framework by which we can speak about objects in the world. He uses two metaphors: first, that these kinds of propositions are like a “river-bed” that allow the “river of language” to flow freely (97, 99); and second, that the propositions are like hinges on a door, which must be fixed in order for the door to function in any significant way (341, 343). These kinds of propositions ostensively defined; they are not making an empirical claim about the external world, but merely show an example and hence demonstrate how the statement is to be used. The possibility of language is not made by actual facts in the world (which the skeptic can always undermine), but by simply never calling into question those facts (creating the “river-bed”).[4] Thus, Wittgenstein does superficially agree with the skeptic that such foundational propositions lie beyond empirical verification, but questions the sensibility and usefulness of such an assertion.

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