or hardly thinking?
|Major trains of thought|
|The good, the bad,|
and the brain fart
|Come to think of it|
|Cogito ergo sum|
Logic and rhetoric
Willard Van Orman Quine (1908–2000) was a 20th century logician and analytical philosopher who mostly focused on topics related to mathematics, logic, and science. He is primarily known as the man who "debunked" the philosophical movement known as logical positivism, and was a paradigm proponent of naturalism. He is often credited as one of the most influential analytical philosophers of the 20th century. A general theme in Quine's philosophy is a skepticism towards truths derivable from the meaning of terms, analytical truths, and a priori knowledge. This sticks Quine into the tradition of empiricism.
Quine rejected the use and value of what he called "first-philosophy", namely philosophy that attempts to establish "first-principles" in topics related to epistemology and metaphysics that is independent of the findings and theories of the natural sciences. For Quine, the history of fields like epistemology in attempts to solve problems independent of the world as described by science (such as in attempt to "solve" problems related to epistemic skepticism, or to provide an unproblematic analysis of knowledge) have shown themselves to be fruitless projects, and such it would be a waste of time to continue engaging with them on the basis of first-philosophy. For Quine, the distinction between domains like philosophy and science are not true distinctions between modes of inquiry; instead, they are merely just a means to organize libraries and school curriculums based on related topics. Quine does not believe there is a true line between where philosophy ends and science begins, and so scientists have just as much authority and relevance to engage in questions typically associated with philosophy, and philosophers to engage in questions typically associated with science. For Quine, epistemology, logic, mathematics, and science are all extensions of related goals, domains, and inquiries.
Quine characterizes science as “refined common sense” in that it is a more systematic and careful extension of our day-to-day knowledge of basic facts. 
This relates to Quine's particular brand of empiricism that entertains that not only are theories and models in science provisional on accumulating evidence, but that principles in logic and mathematics are as well. Quine's empiricism extends his belief in knowledge being specifically related to sensory stimulation and how one makes successful predictions about one's sensory stimulation from conceptual frameworks. 
Rejection of the Two Dogmas
The analytical/synthetic distinction was given voice to by Immanuel Kant in his work the Critique of Pure Reason, which characterized analytical judgements as one's derived from the meaning of concepts in of themselves, such as with the statements "All Bachelors are unmarried" or "Bodies have an extension in space", and synthetic judgements as one's derived from the inference of two (or more) separate concepts taken together to make a new inference, such as with the statement "Bodies on Earth have weight".
For Kant, there was particular interest in establishing the possibility of synthetic a priori knowledge which would characterize metaphysical knowledge; the exact thing that David Hume rejected as being possible. The Logical Positivists in the 20th century had much to agree with when it came to Hume, but had much to disagree with when it came to Kant — but regardless, they held strong to the analytical/synthetic distinction as fundamental to their whole empiricist paradigm.
Then came the closest thing to a rock star moment in Philosophy when Quine published Two Dogmas of Empiricism in 1951, which challenged the legitimacy of that distinction. Not only did the paper attempt to rebuke the analytical/synthetic distinction, it also came to attack the principle of verification that was widespread in Logical Positivism.
The criticism of analyticity comes in the noted ambiguousness as to why "all bachelors are unmarried men" comes to be an analytical truth. The default assumption is because the meaning is shared, but that only suggests that the terms are synonymous — and that only comes to raise the question to what makes words synonymous? Quine's rejects that you can appeal to the dictionary to answer this question because all the dictionary does is provide a list of known synonyms. Another intuition is to say that the terms refer to the same set of objects but considered the phrase "All animals with hearts are animals with kidneys"; "animals with hearts" and "animals with kidneys" denote the same group of animals, but we would not come to say that the phrases mean the same thing and come to express an analytical truth. Another intuition comes to appealing to the notion of modal necessity, but this comes to raise all the relevant objections Quine has for modal logics. Without a means to characterize what analyticity is, it becomes untenably difficult to ascribe a difference between analytical and synthetic judgements.
It should be said that Quine's argument against the analytical/synthetic distinction (though arguably what he is most famous for) is still controversial within philosophy. The argument provided in Two Dogmas against the verification principle, however, is near widely accepted and cited as the "death nail" to logical positivism.
The argument that Quine provides is essentially in the indetermination of sense data to verify propositions in isolation, and so the meaning of propositions cannot be reduced to a certain set of sense experiences and such verified by having said experiences. Propositions have to be taken in a whole network of related theories, background assumptions, and auxiliary hypotheses. No proposition can be "verified" on its own, isolated from this theoretical background of related beliefs and propositions. This may seem in conflict with what was stated about Quine before regarding knowledge and successful predictions with sensory experiences, but the distinction here between Quine and the logical positivists is the logical positivists' thought that a proposition could be verified in isolation to a set of expected sense experiences provided you understood the meaning of the proposition itself -- for Quine a broader holistic conceptual framework is required and the sole "meaning" of the proposition is one to be doubted.
The Indeterminacy of Translation
One of Quine’s most controversial ideas that sort of extends his general skepticism towards analytical truths and proposition-meaning is his stance there is no fact of the matter in determining the “correct” translation from one language to another. If we take something like…
“The snow is white”
we may take it as identical in meaning to the statement in german…
“Der Schnee ist weiß”
But according to Quine there is no basis in assuming that both sentences are determined to have the same objective propositional-meaning. The sub-sections below explains the two major principles as to why.
Indeterminacy of reference
- Quine frames his argument in a thought experiment regarding a field linguist studying a small isolated indigenous community and attempting to determine the meaning of their statements in the fictional language of Arunta.
- Upon seeing a rabbit during a hunt the linguist notices that individuals will use the word “gavagai”. It may be natural to assume that “gavagai” must mean rabbit, but this wouldn’t be a valid inference from the simple observation. In this case “gavagai” could refer to an inseparable individual part of the rabbit, the call to hunt, a superstitious reference to the rabbit being a sign of future bounty, the identification of food, the grass, a command to look, etc.
- A natural response is to state the linguist could ask for clarification, but this requires the linguist themselves to already been immersed within the language.
- According to Quine to understand what is said in a language requires the relevant ontological commitments and relevant grammatical understanding shared within the linguistic community, something only accessible by users of said language.
- It’s not only that the referent can be undetermined in linguistic expression but that the meaning of the individual components of the sentence as well as the sentence as a whole that can be undetermined. This means for Quine that there is no absolute correct way of translating one phrase from one language into the language of another. There is always multiple ways to which a linguistic expression can be translated, and there is no absolute criteria to determine a singular “correct” translation. It should be said that Quine’s use of “holophrastic” does not align with the term’s technical definition within linguistics.
This is not to say that translation is impossible, but rather that when translating from one language to another the possible interpretations are multiple with no singular “correct” translation pre-determined by the linguistic expression itself. That all statements in any language lack any absolute objective propositional meaning.
This is similar to the idea within the philosophy of science where data is said to be underdetermined. The collected quantities have no inherent meaning in of themselves, but instead must be interpreted under a particular investigative context.
Extending his naturalistic stance Quine believed that the topic of epistemology should be the subject of study for natural sciences; namely, for psychology. This view extends Quine's rejection of first-philosophy to which he felt that attempts to analyze knowledge independently from empirical investigation was a waste of time. Quine saw knowledge as being a psychological concept, and such should be the study of psychologists to determine what knowledge is by looking at how knowledge is ascribed in real-world natural contexts. Quine suggested focusing on how sensory inputs were used by a human subject to form models of the external world, possibly conceptualizing knowledge in such cognitive models. Motivating this view is what Quine saw as an utter failure for philosophers to handle from first-principles the problem of radical skepticism and the problem of induction, and he thought there was no advantage apparent to the use of philosophical methods over ones used in psychology. It should be said that for Quine problems related to radical epistemic skepticism were seen as, to put it bluntly, kind of silly. 
A common criticism of this view is that it divorces the prescriptive element to epistemology (in how we ought to conceptualize knowledge) and thus can not be described as genuine epistemology; and another criticism can come in the background assumptions and auxiliary hypotheses used in psychology merely only begging the question against the radical skeptic. For Quine, however, circular reasoning was never a deal breaker for his philosophy, and he was more than comfortable accepting circular arguments within his own philosophy (to an extent). This is likely to due in part to his near anti-foundationalist tendencies within his work, and his adamant rejection of any a priori first-principles being derivable to construct empirical knowledge, and his skepticism of meaning as a whole. Recall Quine rejects the notion there exists analytical truths, that there exists necessary a priori forms of knowledge that can never be rejected upon emerging evidence. This has lead some to characterize Quine as a kind of coherentist, most exemplified in his concept of the web of belief. For Quine, there is no such thing as statements that are universally true that are not dependent on other statements for support. This makes some degree of circularity a necessity. It should also be said that circular reasoning is not by any means a formal fallacy, but an informal one. Circular reasoning is no different then stating that P implies P; such an inference is logically valid by the rules of classical logic. It is just that "God Exists because God Exists" is not a particularly convincing argument, and Quine would have probably agreed with such an argument being characteristically weak. Regardless, a certain degree of toleration towards circularity is something we all engage with to some degree or another — the real question is determining when circularity is actually unacceptable and when it is rationally permissible.
The use/mention distinction is a basic one in analytical philosophy — denoting the distinction between using a word for an intended purpose and merely mentioning a word as an example, placeholder, or to provide a definition, i.e.
- That ball is red — Use.
- Take an arbitrary example of a colour word, i.e "red" — Mention.
Typically, philosophers will use quotes to distinguish when they are using a word or merely just mentioning it. For another example; consider telling someone that there are nine sheep in the pen, and explaining that "nine" and "three to the power of two" denote the same object. Quine frequently made use of criticizing philosophers for confusing use with mention — especially in his critique of the Principia Mathematica where "implies" was given mention in contexts to which it can only be used, a similar criticism was extended to C.I. Lewis in his development of necessary implication. For Quine there was also something to be said that implication can also be viewed as redundant to his concept of "logical truth".
The Quine-Putnam Indispensability Argument
An argument for mathematical realism (or platonism) within the philosophy of mathematics known as the indispensability argument is credited to both philosophers Hilary Putnam and Quine. The argument as generally formulated goes like so…
- P1: All things considered we ought to be ontologically committed to entities indispensable to our strongest scientific theories.
- P2: Mathematical entities are indispensable to our strongest scientific theories.
- C: Therefore, we ought to be ontologically committed to mathematical entities.
The argument is logically valid, and doubles as an argument for various flavors of scientific realism (i.e. being ontologically committed to electrons), but is not without grounds for rejection. Critics if so motivated could reject the first premise as without adequate justification so we are not required to be ontologically committed to the entities indispensable to science. If we accept the first premise, it is a bit harder to justify how mathematical entities are not indispensable to science and it would be the task of the nominalist to argue why if they were to accept that first premise. Quine personally thinks it is inconsistent for a scientific realist to be a realist about unobservable entities (i.e. atoms, electrons, quarks, etc.) but to feel that mathematical objects (i.e. numbers, sets, etc.) do not exist.
A distinction could be made however that being entities that partake in cause and effect, and having location in space and time, the former objects constitute concrete objects and are less philosophically problematic compared to mathematical objects, which are abstract objects that don't exist in time and space, or partake in causal relations. Of course, Quine could just follow up to asking why concrete objects are acceptable while abstract objects are not.
Views on logic
Quine had a limited view on logic, believing it to only contain first-order predicate logic, rejecting set theory, and most of the Principia Mathematica as under the domain of logic. So called "non-classical" logics from intuitionist logic to modal logics were dubbed "deviant logics" by Quine and not considered genuine examples of logic. Many of Quine's ideas regarding logic have not really stood the test of time, with most philosophers coming to reject his views, especially Quine's views on quantified modal logic, to which Saul Kripke having rendered irrelevant with his concept of rigid designators.
Of course, it should be said that Quine himself did not agree, he believed rigid designators implied a kind of essentialism that was untenable. Alternatively, notions of "necessity" seem to imply a degree of analyticity, to which, as established above, Quine had reason to be skeptical of.
Quine rejected conventionalism, which argued that truths in logic were a product of the meaning of terms, thus a product of linguistic convention. Despite this, Quine still wanted to affirm the existence of there being logical truths -- with analyticity and necessity off the table as the means to establishing what logical truths even are. This creates a source of tension in Quine's philosophy, given the difficulty in establishing what makes a statement in formal logic a logical truth without making appeals to conventions in language, the truths being analytical, or notions like necessity as many philosophers are apt to do. This puts Quine in an awkward spot, and some philosophers have argued that Quine never established a satisfactory account of logical truth.
- ↑ 1.0 1.1 1.2  - Stanford Encyclopedia of Philosophy - Quine
- ↑ 2.0 2.1 2.2 Quine, W. V. O. (ed.) (1981). Theories and Things. Harvard University Press.
- ↑ 3.0 3.1 3.2 3.3 Hylton, Peter (2007). Quine: Arguments of the Philosophers. Routledge Publishing.
- ↑ Kant, I. (2003). Critique of pure reason (M. Weigelt, Trans.). Penguin Classics.
- ↑ 5.0 5.1 5.2 Quine, Willard V. O. (1951). Two Dogmas of Empiricism. Philosophical Review 60 (1):20–43.
- ↑ 6.0 6.1 Quine, W. V. (1969). Epistemology Naturalized. In Ontological Relativity and Other Essays. New York: Columbia University Press.
- ↑  - Use/mention confusion - humanities controversies.
- ↑ 8.0 8.1  - Stanford Encyclopedia of Philosophy - Mathematical Indispensability
- ↑ Quine, W.V., 1986. Philosophy of logic. Harvard University Press
- ↑  - Quine on Logic by J. Burgess 1