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.