Two Dogmas of Empiricism

W. V. Quine's paper Two Dogmas of Empiricism, published 1951, is one of the most celebrated papers of twentieth century philosophy in the analytic tradition. The paper is an attack on two central parts of the logical positivists' philosophy. One is the distinction between analytic truths and synthetic truths, explained by Quine as truths grounded only in meanings and independent of facts, and truths grounded in facts. The other is reductionism, which is the theory that each meaningful statement gets its meaning from some logical construction of terms which refers exclusively to immediate experience.

"Two Dogmas" is divided into six sections. The first four sections are focused on analyticity, the last two sections on reductionism. There, Quine turns the focus to the logical positivists' theory of meaning. He also presents his own holistic theory of meaning.

Analyticity and circularity
Most of Quine's argument against analyticity in the first four sections is focused on showing that different explanations of analyticity are circular. The main purpose is to show that no satisfactory explanation of analyticity has been given.

Quine begins by making a distinction between two different classes of analytic statements. The first one is called logical true and has the form:


 * (1) No unmarried man is married

A sentence with that form is true independent of the interpretation of man and married, so long as the logical particles "no", "un-", "and" etcetera have their ordinary English meaning.

The statements in the second class have the form:


 * (2) No bachelor is married.

A statement with this form can be turned into a statement with form (1) by changing synonyms with synonyms, in this case bachelor with unmarried man. It is the second class of statements that lack characterization according to Quine. The notion of the second form of analyticity leans on the notion of synonymy, which Quine believes is in as much need of clarification as analyticity. Most of Quine's following arguments are focused on showing how explanations of synonymy end up being dependent on the notions of analyticity, necessity, or even synonymy itself.

How do we reduce sentences from the second class to a sentence of class (1)? Some might propose definitions. "No bachelor is married" can be turned into "No unmarried man is married" because "bachelor" is defined as "unmarried man". But, Quine asks: how do we find out that "bachelor" is defined as "unmarried man"? Clearly, a dictionary would not solve the problem, as a dictionary is a report of already known synonyms, and thus is dependent on the notion of synonymy, which Quine holds as unexplained.

A second suggestion Quine considers is an explanation of synonymy in terms of interchangeability. Two linguistic forms are (according to this view) synonymous if they are interchangeable without changing the truth-value. That is, in all contexts without change of truth value. But consider the following example:


 * (3)"Bachelor" has less than ten letters.

Obviously "bachelor" and "unmarried man" are not interchangeable in that sentence. To exclude that example and some other obvious counterexamples, such as poetic quality, Quine introduces the notion of cognitive synonymy. But does interchangeability hold as an explanation of cognitive synonymy? Suppose we have a language without modal adverbs like "necessarily". Such language would be extensional, in the way that two predicates which are true about the same objects are interchangeable again without altering the truth-value. Thus, there is no assurance that two terms that are interchangeable without the truth-value changing are interchangeable because of meaning, and not because of chance. For example, "creature with a heart" and "creature with kidneys" share extension.

In a language with the modal adverb "necessarily" the problem is solved, as salva veritate holds in the following case:


 * (4) Necessarily all and only bachelors are unmarried men

while it does not hold for


 * (5) Necessarily all and only creatures with a heart are creatures with kidneys.

But to say (4) is according to Quine to say that the sentence "All and only all bachelors are unmarried men" is analytic. So for salva veritate to hold as a definition of synonymy, we need a notion of necessity and thus of analyticity.

Reductionism and Quine's holism
According to the logical positivists, a statement was given a meaning by its empirical verification. This view can be used to define synonymy. Two terms would be synonymous if and only if they are alike in method of empirical confirmation or infirmation. With the notion of synonymy, analyticity of the second class could be defined, and the problem would be solved. But Quine points out that this view needs an explanation of the methods which are to be compared. Reductionism is one of these methods, where a meaningful statement gets its meaning from some logical construct of terms which only refers to immediate experience. Reductionism depends on the assumption that each statement alone can admit of confirmation or infirmation. Quine however believes that all our statements "face the tribunal of sense experience not individually but only as a corporate body".

Quine holds these two theses as deeply connected with each other. When each statement is verified alone, it seems significant to talk about statements that are vacuously confirmed.

Instead of reductionism, Quine proposes that it is the whole field of science and not single statements that are verified. All scientific statements are interconnected in a force field. Logical laws give the relation between different statements, while they also are statements of the system. This makes talk about the empirical content of a single statement misleading. It also becomes impossible to draw a line between synthetic statements, which depend on experience, and analytic statements, that hold come what may. Any statement can be held as necessarily true according to Quine, if the right changes are done somewhere else in the system. In the same way, no statements are immune to revision.

Even logical laws can be revised according to Quine. Quantum logic, introduced by Garrett Birkhoff and John von Neumann, abandons the law of distributivity from classical logic in order to reconcile some of the apparent inconsistencies of classical boolean logic with the facts related to measurement and observation in quantum mechanics. Quine makes the case that the empirical study of physics has furnished apparently credible grounds for replacing classical logic by quantum logic, rather as Newtonian physics gave way to Einsteinian physics. The idea that logical laws are not immune to revision in the light of empirical evidence has provoked an intense debate, which we discuss in the article Is logic empirical?.

According to Quine, there are two different results of his reasoning. The first is a blurring of the line between metaphysics and natural science. Our theory about physical objects is epistemologically comparable to the gods of Homer. Quine believes in physical objects and considers it a scientific error not to, but not because of some epistemic difference in kind, but because the theory of physical objects has turned out to be a more efficient theory.

The second result is a move towards pragmatism. While pragmatic concerns are important for Carnap and other logical positivists when choosing linguistic framework, their pragmatism ends there. For Quine, every change in the system of science is, when rational, pragmatic.

Critique and influence
Grice and Strawson criticized "Two Dogmas" in their text In Defence of a Dogma. Among other things, they argue that Quine's skepticism about synonyms leads to a skepticism about meaning. If statements can have meanings, then it would make sense to ask "What does it mean?". If it makes sense to ask "What does it mean?", then synonymy can be defined as follows: Two sentences are synonymous if and only if the true answer of the question "What does it mean?" asked of one of them is the true answer to the same question, asked of the other. They also draw the conclusion that discussion about correct or incorrect translations would be impossible given Quine's argument. Four years after Grice and Strawson published their paper, Quine's book Word and Object was released. In the book Quine presented his theory of indeterminacy of translation.

In 'Two Dogmas' revisited, Putnam argues that Quine is attacking two different notions. Analytic truth defined as a true statement derivable from a tautology by putting synonyms for synonyms is near Kant's account of analytic truth as a truth whose negation is a contradiction. Analytic truth defined as a truth confirmed no matter what however, is closer to one of the traditional accounts of a priority. While the first four sections of Quine's paper concern analyticity, the last two concern a priority. Putnam considers the argument in the two last sections as independent of the first four, and at the same time as Putnam criticizes Quine, he also emphasizes his historical importance as the first top rank philosopher to both reject the notion of apriority and sketch a methodology without it.

In his book Philosophical Analysis in the Twentieth Century, Volume 1 : The Dawn of Analysis Scott Soames (pp 360-361) has pointed out that Quine's circularity argument needs two of the logical positivists central theses to be effective:


 * All necessary (and all a priori) truths are analytic


 * Analyticity is needed to explain and legitimate necessity.

It is only when these two theses are accepted that Quine's argument holds. It is not a problem that the notion of necessity is presupposed by the notion of analyticity if necessity can be explained without analyticity. According to Soames, both theses were accepted by most philosophers when Quine published Two Dogmas. Today however, Soames holds both statements to be antiquated.