Empiricism and Positivism

Wiliam Of Occam (c. 1340) denied that Plato's forms were real; instead all that's real are particular things, some of which are given a common name because of things they have in common; e.g., there's no such thing as "dog-ness", there are just many animals with similar characteristics, to which we give the name "dog;" this position is called "nominalism" since it emphasizes names as opposed to real universal essences going beyond the obsrvable things themselves; sensory experience is all that is needed for knowledge - not some form of reason to go beyond what experience tells us.

Francis Bacon (c. 1620) proposed that science should have no theories, hypotheses, deductions, but only INDUCTION - sheer collection and tabulation of the facts of experience as empirically observed over time; observations could lead to summary generalizations - as opposed to the science Galileo and Newton were founding, in which general principles allowed one to deduce what particular observations would occur; the Galilean / Newtonian deductive approach won out over the Baconian inductive approach, though Bacon's views returned with Comte and Skinner

David Hume (c. 1748) attempted to make a philosophy based on Newton's science, but in his belief that cause was illusion and we have only the habit of observing events and generalizing from them, he actually stayed closer to the Baconian model; ironic, because Newton had tried to be very Baconian and not form any hypothetical entities ("Hypothesi non fingo," he wrote in Latin), but in developing his theory based on force and matter and gravity, etc., he did assume the reality of those unobservable hypothetical things

August Comte (c. 1842) developed a philosophy of positivism in which the empiricism of science was the model for all thought; only publicly observable experiences, uncontroversially shared by everyone, should be the subject matter for science, and all knowledge was basically empirical observation

Ernst Mach (c. 1883) went further than Comte and said it wasn't actually the physical events that could be observed, but only the individual's sense experience of those events; science had to be about describing which sense experiences went together, and which ones led to which other ones, without proposing any theoretical entities to "explain" why that should be the case; he translated laws of mechanics into descriptions of correlated sense experiences

B.F. Skinner (c. 1953) followed Bacon (and Comte and Mach) in his learning theory and described the effects of reinforcement on behavior as a catalog of how certain observable reinforcement conditions change certain observable behavior frequencies - without ever trying to "explain" those relationships in other terms - not cognitive ("cognitive maps"). not physiological ("motivation," "inhibition"), not even psychological ("habit strength"), but just behavioral: reinforcement is defined simply as "anything that increases the frequency of a response"; this agnostic view of the reality underlying science is shared by many, if not most, contemporary physicists, especially in the field of quantum mechanics

Logical Positivism (c. 1924) arose in the wake of Einstein's relativity theory and the birth of quantum theory in physics, when philosophers were suddenly confronted with the fact that they HAD been mistaken in accepting Newton's world view after all; they knew they needed to stick to observations and not hypothesize things like "the force of gravity" anymore, since that force had turned out to be an illusion; yet they still wanted to use hypothetical entities like "atoms" in their theories; the solution was to define those theoretical entities in terms of the concrete observational terms they used in measuring the appearances of atoms and the like; if the terms were thus strictly tied to the data, the science couldn't go far wrong

Karl Popper (c. 1935) soon argued that observations were dependent on theory in the first place so the distinction between the two types of terms was not so clear; also argued that support for a theory could never prove it true inductively, and many wrong theories had nevertheless collected many confirmatory observations - but a good theory would survive systematic attempts to prove it false as well; "failure to be disconfirmed" was the highest status for a theory, so if a theory couldn't possibly be proven false by any conceivable observation, it shouldn't even be considered science

Thomas Kuhn (c. 1962) showed that historically, the major changes that happened in science were not due to the kind of rational progression of ideas imagined by philosophers, but instead were due to sociological factors involving prior commitments to theories that dictated which observations were relevant and how they should be interpreted - again making very implausible the claims of the logical positivists about pure observation and empirical definition of every theoretical term

A Brief Outline of Logical Positivism

- philosophical movement of the 1920's and 30's spearheaded by the Vienna Circle, a group of philosophers including Carnap and Schlick, who pursued an empiricist scientific philosophy in the tradition of David Hume (and more recently of Bertrand Russell and early work of Ludwig Wittgenstein); brought to the English-speaking world largely by A.J. Ayers's (1935) Language, Truth and Logic.

- proposed science as the model for all knowledge and truth; saw philosophy's task as the formalization of scientific method and the analysis of language in order to clarify scientific propositions and thereby avoid misleading interpretations of its concepts and theories

- asserted that the foundation of science was concrete experience; evidence about any empirical hypothesis (Hume's "matters of fact") must be publicly observable, i.e., available to anyone and unambiguously interpretable by anyone -- unlike, for instance, the data of introspection, which are available only to the introspector

- the powerful apparatus of modern symbolic logic (the framework for what Hume had called "relations among ideas") was added to empirical observation to support the construction of sophisticated scientific theories

- the meaning of a statement was taken to be its method of verification, the procedure for deciding the truth of the statement; any (non-analytic) statement which could not, at least in principle, be verified through observation, was held to be metaphysical and therefore meaningless -- which included statements about morals, theology, aesthetics, and most of Hegel's idealism (the nineteenth century's predominant philosophical world view)

- closely related to verificationism was Bridgman's (1927) independently developed principle of operationism, which said that theoretical terms which described unobservable entities (e.g., "electrons") were to be tied to specific observations based on the actual physical operations used to gather evidence about them (e.g., emission lines on a spectrometer)

- logical positivism's significance for psychology was the assertion that statements about mental states and operations would turn out to correspond exactly to statements about observable behaviors, so that one could translate problematic propositions about cognitive phenomena into scientifically testable propositions about overt actions

- examples of problems that later emerged for the approach: in physics, a single concept like distance requires completely different operational definitions for "distance between two points on a yardstick" and "distance between two stars", leading to the strange conclusion that these are actually two different concepts; in psychology, attributing "having a headache" to a person who moans, holds his head, takes aspirin, etc., has exactly the same observational basis as the attribution of "faking a headache" -- thus making the distinction between the two states meaningless!

Neobehaviorism - modification, beginning around 1930, of the behaviorist approach proposed by Watson and Guthrie, to reflect growing sophistication in the attempt to account for knowledge in terms of observable behavior; four key elements were:

(1) the influence of logical positivism and operationism

(2) the use of animals in research, reflecting the confidence of behaviorist psychologists that their principles were sufficiently universal, well-established, and widely held that findings based on easily manipulated, controlled, and observed animals would be seen as generalizable to all instances of learning, including that of humans

(3) an emphasis on learning as the crucial psychological process in animals, since it represents (for the empiricist) the source of every facet of behavior and provides the means for adapting to a changing environment throughout the animal's lifespan

(4) a willingness to construct increasingly complex theories of behavior, using the concept of the "intervening variable" to represent cognitive abilities and other unobservables, and departing from the traditional straightforward connection, by some proposed mechanism, of observable stimuli and responses

from A.J. Ayer (1935), Language, Truth and Logic

PREFACE TO FIRST EDITION

THE VIEWS which are put forward in this treatise derive from the doctrines of Bertrand Russell and Wittgenstein, which are themselves the logical outcome of the empiricism of Berkeley and David Hume. Like Hume, I divide all genuine propositions into two classes: those which, in his terminology, concern "relations of ideas," and those which concern "matters of fact." The former class comprises the a priori propositions of logic and pure mathematics, and these I allow to be necessary and certain only because they are analytic. That is, I maintain that the reason why these propositions cannot be confuted in experience is that they do not make any assertion about the empirical world, but simply record our determination to use symbols in a certain fashion. Propositions concerning empirical matters of fact, on tne other hand, I hold to be hypotheses, which can be probable but never certain. And in giving an account of the method of their validation I claim also to have explained the nature of truth.

To test whether a sentence expresses a genuine empirical hypothesis, I adopt what may be called a modified verification principle. For I require of an empirical hypothesis, not indeed that it should be conclusively verifiable, but that some possible sense-experience should be relevant to the determination of its truth or falsehood. If a putative proposition fails to satisfy this principle, and is not a tautology, then I hold that it is metaphysical, and that, being metaphysical, it is neither true nor false but literally senseless. It will be found that much of what ordinarily passes for philosophy is metaphysical according to this criterion, and, in particular, that it can not be significantly asserted that there is a non-empirical world of values, or that men have immortal souls, or that there is a transcendent God.

As for the propositions of philosophy themselves, they are held to be linguistically necessary, and so analytic. And with regard to the relationship of philosophy and empirical science, it is shown that the philosopher is not in a position to furnish speculative truths, which would, as it were, compete with the hypotheses of science, nor yet to pass a priori judgements upon the validity of scientific theories, but that his function is to clarify the propositions of science by exhibiting their logical relationships, and by defining the symbols which occur in them. Consequently I maintain that there is nothing in the nature of philosophy to warrant the existence of conflicting philosophical "schools." And I attempt to substantiate this by providing a definitive solution of the problems which have been the chief sources of controversy between philosophers in the past.

The view that philosophizing is an activity of analysis is associated in England with the work of G. E. Moore and his disciples. But while I have learned a great deal from Professor Moore, I have reason to believe that he and his followers are not prepared to adopt such a thoroughgoing phenomenalism as I do, and that they take a rather different view of the nature of philosophical analysis. The philosophers with whom I am in the closest agreement are those who compose the "Viennese circle," under the leadership of Moritz Schlick, and are commonly known as logical positivists. And of these I owe most to Rudolf Carnap. Further, I wish to acknowledge my indebtedness to Gilbert Ryle, my original tutor in philosophy, and to Isaiah Berlin, who have discussed with me every point in the argument of this treatise, and made many valuable suggestions, although they both disagree with much of what I assert. And I must also express my thanks to J. R. M. Willis for his correction of the proofs.

A. J. AYER.

11 Foubert's Place,

London.

July 1935.