Akron, Ohio, 1908–2000
W. V. O. Quine
The most influential American philosopher of his century took apart the two assumptions that modern empiricism rested on, and replaced the image of knowledge as a building with the image of a web.
The view
Willard Van Orman Quine spent almost his whole career at Harvard. His 1951 paper "Two Dogmas of Empiricism" attacked the view he had learned from the logical positivists in Vienna and Prague.
The first dogma is that truths divide cleanly into two kinds: analytic ones, true by the meanings of their words, and synthetic ones, true by how the world is. Quine argued that nobody has drawn that line without assuming it. The second dogma is that each meaningful statement can be matched to its own set of confirming and refuting experiences. Quine denied this as well.
In their place he put holism. A single hypothesis never implies an observation by itself. It needs the help of other theories, assumptions about instruments, and logic and mathematics too. So when a prediction fails, logic does not say which of them is at fault.
The argument
The image Quine offers is a web, or a field of force, that touches experience only along its edges. Near the edge are reports of observation. Further in are the laws of physics. At the centre are logic and mathematics.
A conflict with experience at the edge forces a change somewhere inside, but nothing fixes where. Any statement can be held true if we adjust enough of the others, and none is immune from revision. After Quine, "Two Dogmas of Empiricism"
We revise so as to disturb the whole as little as possible, which is why we give up an observation report readily and a law of logic almost never. That is a matter of degree and convenience. Even logic could go, and Quine notes that some physicists have proposed revising it to simplify quantum mechanics.
Two consequences follow. Theory is underdetermined by evidence: more than one web can fit the same experience. And philosophy has no standpoint outside science from which to justify science. In "Epistemology Naturalized" (1969) Quine proposed that the theory of knowledge become a chapter of psychology, studying how a human being turns the meagre input at the sensory surfaces into a torrent of theory.
Where he meets Deutsch
Holism about testing is common ground. Popper had made the same point in 1934: a test always involves background knowledge, and a refutation can be deflected onto an auxiliary assumption. Deutsch agrees that no statement is tested alone and that every part of our knowledge, logic included, is open to revision.
They share the rejection of foundations. Neurath's boat is a fair picture of fallibilism: there is no dry dock, and repairs are made afloat.
Where they part
Quine dropped two dogmas of empiricism and kept empiricism. All evidence, he held, is sensory evidence, and theories are in the end devices for predicting stimulation. Deutsch regards that as the original mistake. Theories are explanations of what is really there. Prediction is how we test them, and it is not what they are for.
Underdetermination looks different once explanation is the standard. Logic may permit us to save any hypothesis by adjusting the rest of the web. But an adjustment made only to save it is easy to vary and explains nothing, so it makes the web worse. Among rival webs that fit the data, almost all are bad explanations. The choice between the remainder is settled by argument, and it is not a matter of taste or economy.
Naturalising epistemology gives up the question Deutsch cares about. A psychology of how input becomes output could describe what scientists do. It would not say why one theory is better than another. And Quine's behaviourism, in which knowing is a disposition to respond to stimuli, leaves out the thing to be explained: how a mind creates an idea that was in none of its inputs.
| Quine | Deutsch | |
|---|---|---|
| Where does knowledge come from? | Sensory stimulation, organised by the whole web of theory. | Conjecture: guesses, improved by criticism and experiment. |
| What does justification do? | Beliefs are supported together, never one by one, and chosen for simplicity and fit. | Nothing. No theory is ever justified, and none needs to be. |
| Can knowledge grow without limit? | The web can always be revised, but its only evidence is what reaches the senses. | Yes. Problems are inevitable, and problems are soluble. |
| What is knowledge, physically? | Dispositions of a nervous system to respond to stimulation. | Information that, once embodied, tends to keep itself in existence. |
Further reading
- W. V. O. Quine, "Two Dogmas of Empiricism", in From a Logical Point of View (1953).
- W. V. O. Quine, "Epistemology Naturalized", in Ontological Relativity and Other Essays (1969).
- W. V. O. Quine and J. S. Ullian, The Web of Belief (1970): written for students.
- Willard Van Orman Quine, Stanford Encyclopedia of Philosophy.