Chapter 2: Empiricism

Empiricism is often summarized with the claim that the only source of knowledge is experience.

The most important stage in the development of empiricist philosophy was in the seventeenth and eighteenth centuries, with the work of John Locke, George Berkeley, and David Hume.

\ “Classical” forms of empiricism were based upon theories about the mind and how it works. Their view of the mind is sometimes called “sensationalist”. Sensations, like patches of color and sounds, appear in the mind and are all the mind has access to. The role of thought is to track and respond to patterns in these sensations.

Empiricists have often tended to think of the mind as confined behind a “veil of ideas” or sensations. The mind has no access to anything outside the veil.

\ A problem for empiricism has been a tendency to lapse into skepticism, the idea that we cannot know anything, or can only know much less than is usually supposed, about the world and its workings.

• External world skepticism: questions whether we can ever know anything about a physical world that might lie behind the flow of sensations we receive.
• Inductive skepticism: why do we have a reason to think that the patterns found in past experiences will also hold in the future?

\ It is common to talk of a battle between the “rationalists” and “empiricists” in the seventeenth and eighteenth centuries. Rationalists believed that pure reasoning can be a route to knowledge that does not depend on experience. Mathematics seemed to be a compelling example of this kind of knowledge. The term “rationalism” was often used in a broad way, to indicate confidence in the power of human reason.

Empiricists insisted that experience is our only way of finding out what the world is like.

In the late eighteenth century, a sophisticated intermediate position was developed by Immanuel Kant. Kant argued that all our thinking involves a subtle interaction between sensory experience and preexisting mental structures that we use to make sense of experience. Concepts, such as space, time, and causation cannot be derived from experience because a person must already have these concepts in order to use experience to learn about the world. Kant also held that mathematics gives us genuine knowledge but does not require experience for its justification.

\ Making a sweeping generalization, it is fair to say that the empiricist tradition has tended to be (1) pro-science, (2) worldly rather than religious, and (3) politically moderate or liberal. Empiricist ideas have tended to be allies of a practical, scientific, down-to-earth outlook.

\ The Vienna Circle and logical positivism

A new form of empiricism was developed in Europe after World War I by a group of people who were scientifically oriented and thought they could avoid many of the problems with traditional forms of empiricism. This group has become known as the “Vienna Circle”. The usual name for the view the Vienna Circle developed is “logical positivism”.

The logical positivists were inspired by developments in science in the early years of the twentieth century. They also thought that developments in logic, mathematics, and the philosophy of language had shown a way to put together a new kind of philosophy. Logical positivism was a plea for Enlightenment values, in opposition to mysticism, Romanticism, and nationalism. The positivists championed reason over the obscure, the logical over the intuitive. The logical positivists were also internationalists, and liked the idea of a universal and precise language that everyone could use to communicate clearly.

Many of the Vienna Circle had socialist leanings, some were Jewish, and there were certainly no Nazis. So the logical positivists were persecuted by the Nazis, to varying degrees.

\ Earlier empiricist views were based on views about the mind and perception. Logical positivism, in contrast, was based in large part on theories about language - especially about what language can and can’t express. Their central idea was the verifiability theory of meaning: knowing the meaning of a sentence is knowing how to verify it. If a sentence has no possible method of verification, it has no meaning.

To explain: By “verification”, the positivists meant by means of observation. The positivists had testability in mind, because testing is an attempt to work out whether something is true or false.

The verifiability theory was only supposed to apply to a particular kind of meaning, the kind seen when a person is trying to state something about the world.

There are parts of languages that are supposed to have factual meaning, and are supposed to say something about the world, and fail to do so. For the logical positivists, this includes most traditional philosophy, much of ethics, and theology as well.

A second part of positivists’ view of language is the distinction between analytic and synthetic sentences.

• analytic sentences are sentences that are true or false simply in the virtue of the meaning of the words within them, regardless of how the world happens to be. Analytic truths are, in a sense, empty truths with no factual content.
• synthetic sentences are true or false in virtue of both the meaning of the words in the sentence, and how the world actually is.

\ Another part of their view of language which brings us closer to issues about science, is a distinction they make between observational and theoretical language. Usually the distinction between these was applied to individual terms. “Red” might be put in the observational language, while “electron” in the theoretical part.

\ Though traditional philosophy was largely seen as a waste of time, logical positivists did think there were some real tasks for philosophers to do. They saw logic as the main tool for philosophy, including philosophical discussion of science. The most useful thing that philosophers can do is give logical analyses of how language, mathematics, and science work. Logic, in general, is the attempt to give an abstract theory of what makes some arguments compelling.

\ In short: Logical positivism was a revolutionary version of empiricism, based largely on a theory of language. The aim of science - and the aim of everyday thought and provlem-solving as well - is to track and anticipate patterns in experience. We can make rational predictions about future experiences by attending to patterns in past experiences, but we nevet get a guarantee. We could always be wrong. There is no alternative route to knowledge besides experience; when philosophy has tried to find such a route, it has lapsed into meaninglessness.

\ Problems

There was considerable difficulty in getting a good formulation of the verifiability principle. For example, if we could empirically show the first part of the claim to be false, then the whole claim would be shown false (if A is false, then A&B must be false too, no matter what B is) because of the logic of statements containing “and”.

Quine argued for a holistic theory of testing. He argued that mainstream empiricism had been committed to a badly simplistic view of testing. Logical positivism, he said, must be replaced with a holistic version of empiricism.

A holist argues that you cannot understand a particular thing without looking at its place in a larger whole. Holism about testing says we cannot test a single hypothesis or sentence in isolation. Instead, we can only test complex network of claims and assumptions. This is because only a complex network of claims and assumptions makes definite predictions about what we should observe. Whenever you think of yourself as testing a single idea, what you are really testing is a long, complicated conjunction of statements. It is the whole conjunction that gives you a definite prediction.

However, logical positivists already accepted that testing is holistic. Hertbert Feigl said that no scientific assumption is testable in complete isolation. Only whole complexes of inter-related hypotheses can be put to the test.

\ Quine also argued that there is no way to make scientific sense of a sharp analytic/synthetic distinction. He connected this point to his holism about testing. For Quine, all our ideas and hypotheses form a single “web of belief”, which has contact with experience only as a whole. An unexpected observation can prompt us to make a great variety of possible changes to the web.

\ For the traditional empiricist philosopher, understanding scientific theorizing in a way that posits a layer of observable phenomena and a layer of hidden structure responsible for the phenomena takes us too close to bad old philosophical views like Plato’s. We are too close for comfort, so we must give a different kind of description of how science works. The result is the insistence that, ultimately, the only thing that language can do is describe patterns in the observable realm. It was written: “in science there are no ‘depths’; there is surface everywhere”. This is a vivid expression of the empiricist aversion to a view in which the aim of theorizing is to describe hidden levels of structure. Science uses unusual theoretical concepts, which initially look like attempts to refer to hidden things, as a way of discovering and describing subtle patterns in the observable realm.

So the logical positivists and the logical empiricists talked continually about prediction as the goal of science. Prediction was a substitute for the more obvious-looking, but ultimately forbidden, goal of describing the real hidden structure of the world.

\ Changes

In the years after World War II, the analytic/synthetic distinction was regarded as questionable for the logical positivists now referred to as logical empiricists.

The verifiability theory was replaced with a holistic empiricist theory of meaning. Theories were seen as structures that connect many hypotheses together. There structures are connected, as wholes, to the observable realm, but any part of a theory, claim, hypothesis, concept, etc., does not have some specific set of observations associated with it.

\ Logical positivists views about the role of logic in philosophy were basically unchanged. For Hempel, to explain something is to show how to infer it using a logical argument, where the premises of the argument include at least one statement of a natural law.

As an empiricist, Hempel was attracted to the idea that the only possible role for those parts of language that seem to refer to unobservable entities is to help us pick out patterns in the observable realm.

\ Feigl himself said the logical positivists were right to emphasize the role of observation in providing evidence for our claims, but they pushed this emphasis so far that they lost sight of the objects that these claims are typically about. He stated that the positivists, with their eyes fixed on evidence, were not seeing what lies beyond that evidence.

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