Two dogmas of empiricism

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Two Dogmas of Empiricism (original title: Two Dogmas of Empiricism ) is one of the most important essays by the American philosopher Willard Van Orman Quine and thus one of the most important essays in analytical philosophy . He first appeared in 1951 in the journal Philosophical Review, then later in the anthology Von einer logischen Standpunkt ( From a Logical Point of View, 1953).

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The two " dogmas " of empiricism attacked by Quine are:

  • epistemological reductionism . This states that a theory can be broken down into individual statements that can each be empirically tested for themselves.
  • the distinction between analytical and synthetic sentences . According to the discussion in the analytical philosophy of that time, this means that the truth of some sentences (the analytical) results solely from the partial expressions used in them, whereas the truth of the other sentences (the synthetic) derives from their agreement with reality.

Section 1: Background for analyticity

For the distinction "analytical / synthetic", which according to Quine goes back to Leibniz , Hume and Kant , the following sentences serve Quine as an example:

  • All bachelors are unmarried.
  • All living things that have a heart also have kidneys.

Both sentences are true , but there seems to be an important difference between their truths: the first sentence is true solely because of the meaning of the words involved, especially because “bachelor” means “unmarried man”. The second sentence is true on the basis of empirical facts, that is, that it is true could not be found out just by thinking about the meanings of the words "heart", "kidney" and "living being", but only through a scientific investigation.

Quine's aim is to highlight this intuitively plausible distinction as unfounded. His strategy for doing this is rather indirect: He examines a number of ways to make this distinction explicit , and shows that each of these possibilities fails to achieve the objective.

First, Quine emphasizes the close connection between analyticity and synonymy : An analytical statement can be transformed into a logical truth by replacing synonymous terms for one another. For example, the analytical proposition

All bachelors are unmarried.

into the logical truth

All unmarried men are unmarried.

translated by replacing the term “bachelor” with the synonymous “unmarried man”. Because of this close connection, Quine's criticism is directed against both the concept of analyticity and that of synonymy. In the following, he examines a number of ways to clarify one of these two terms.

Section 2: Definition

The attempted explanation here is that terms are synonymous due to a definition , that is, that “bachelor” is defined as “unmarried man”. Quine's answer is that a definition, e.g. B. is in a dictionary, to be correct, must already be based on a previous language usage and therefore cannot be regarded as a reason for synonymy.

Section 3: Substitutability

Another way is to say that synonymous expressions are substitutable for one another in all contexts . “Bachelor” and “unmarried man” are therefore synonymous, because one can move from the sentence “necessarily all bachelors are bachelors” to “necessarily all bachelors are unmarried”. Quine points out, however, that this test can only distinguish analytical truths from merely empirical truths such as “All heart-shaped beings are kidney-shaped beings” only if the substitution is made in opaque contexts , ie the sentences in which the substitution is made already Include intentional adverbs as necessary . These expressions are only understandable if one already assumes an analytical understanding of the expression , which is to be clarified.

Section 4: Semantic Rules

In formal systems the analyticity of natural languages ​​can be modeled using so-called "semantic rules" (sometimes also called "meaning postulates"). According to Quine, however, this phenomenon appears as an irreducible fact - the “mental, behavioral or cultural factors” that are relevant to it are not discussed. It is therefore an overly simplistic model that has no explanatory value for the problem at hand.

Section 5: Verificationism and Reductionism

The final proposal examined by Quine to clarify the concept of synonymy is that two statements are synonymous if they have the same empirical verification conditions . An example of the term verification condition: The sentence “Objects A and B are equally heavy” could have the following verification condition: “If you place A and B on both sides of a beam balance, it aligns horizontally”.

In the case of “radically reductionist” empiricism, the verification conditions themselves must in turn translate into statements about “sensory data”, ie about direct experiences. Such statements could look something like this: "I have a red sensation here and now".

Rudolf Carnap attempted such a reduction in his book The Logical Structure of the World (1928). According to Quine, however, he failed, he himself saw his project as a failure, since he never again advocated such a reductionism in his later publications.

At this point it becomes clear how the two dogmas criticized by Quine, the existence of analytical sentences and the reduction to sensory experience, are related: Quine says that both are based on the same idea, namely that the truth of a sentence is divided into a linguistic and a factual component split up ("that the truth of a statement is somehow analyzable into a linguistic component and a factual component"). Let two sentences with the same linguistic component be synonymous; in the case of an analytical sentence, the factual component is zero. According to the reductionist idea, the factual component must be identified with confirmation through sensory experience.

The reason why this notion, according to Quine, is wrong is that it is based on the fact that empirical confirmation and refutation take place at the level of sentences, that is to say, that they are sentences which are classified as true or false in the face of sensory experience. According to Quine, however, it is not individual sentences that are confirmed or refuted, but groups of sentences, that is, entire theories. Sentences about the outside world would not stand alone before the tribunal of sense experience, but together ("My countersuggestion [...] is that our statements about the external world face the tribunal of sense experience not individually but only as a corporate body"). Quine points out that Pierre Duhem formulated a similar thought before him ; the view is therefore also known as the Duhem-Quine thesis .

Section 6: Empiricism Without Dogmas

In the sixth and last section, Quine presents an alternative to empiricism with the two dogmas. He dresses this design in a vivid picture: According to this picture, the entirety of the scientifically recognized sentences forms a net-like, spherical structure. At the periphery of this sphere lie the sentences that deal with sensory experiences, closer to the center are sentences that have fundamental laws as their object, such as the laws of physics , and even further inside the laws of mathematics and logic . The sentences are related to one another through the laws of logic, that is, if a sentence that was previously held to be true (false) turns out to be false (true), then according to the laws of logic other sentences must also be corrected in their truth value.

Here is an example: Let us consider the sentence set {"All people are mortal", " Socrates is a person", "Socrates is mortal"}. Now suppose that it turns out that Socrates is not really mortal, but immortal. Then, in order to ensure the consistency of the system , we must also give up one of the other two sentences.

Quine's point now lies in the fact that it cannot be said in advance which sentences we would give up in such a conflict case, i.e. whether we would decide in the above example to say that not all people are mortal or that Socrates is not human. According to Quine, you can in principle hold on to any sentence, regardless of how new experiences look. For example, if a new empirical experience contradicts a sentence on the periphery, this can be retained, for example by declaring the new experience to be a hallucination . Conversely, no sentence is immune to revision either. It has been suggested that even logical laws such as the principle of the excluded third be abandoned in order to simplify quantum physics , for example . A modification of the logical laws would mean that not only the corresponding sentences change, but also the rules according to which the truth values ​​are propagated in the network.

In fact, according to Quine, in the case of a new, contradicting experience, there is a "natural tendency" to disturb the system as little as possible and therefore to correct the sentences on the periphery rather than those in the center. However, no sharp line can be drawn here. With Quine this consideration leads to the provocative thesis that there is no fundamental difference between the belief in physical objects and the belief in the gods of Homer . In both cases it is a question of culture-related settlements . The conception of the physical objects has proven to be “more efficient, to incorporate a manageable structure into the flow of experiences” (“it has proved more efficacious […] as a device for working a manageable structure into the flux of experience”). Both conceptions are, however, underdetermined by experience , ie the existence of physical objects cannot be proven with reference to experience either.

At the end of his essay, Quine is thus committed to a consistent pragmatism : considerations that lead people to distort his scientific tradition in order to adapt it to his continuous sensory input are, where rational, pragmatic ("the considerations which guide [man]] in warping his scientific heritage to fit his continuing sensory promptings are, where rational, pragmatic ").

literature

  • Christian Nimtz: Willard VO Quine. The distinction between analytical and synthetic sentences. In: Ansgar Beckermann / Dominik Perler (eds.): Reclam's classics of philosophy today. Reclam, Stuttgart 2004.
  • WVO Quine: Two dogmas of empiricism. In: ders .: From a logical point of view. Nine logical-philosophical essays. Ullstein, Frankfurt a. M./Berlin/Wien 1979, pp. 27-50.
  • Elliott Sober: Quine's Two Dogmas. In: Proceedings of the Aristotelean Society, Supplementary Vol. 74, 2000, pp. 237-280.

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