On Some Methodological Problems of Psychology Gustav Bergmann Philosophy of Science, Vol. 7, No. 2. (Apr., 1940), pp. 205-219. Stable URL: http://links.jstor.org/sici?sici=0031-8248%28194004%297%3A2%3C205%3AOSMPOP%3E2.0.CO%3B2-1 Philosophy of Science is currently published by The University of Chicago Press.
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O n Some Methodological
Problems of Psychology
BY
GUSTAV BERGMANN
T T H E end of the last century, there began a movement away from traditional philosophy and towards a closer contact of philosophical thought with empirical science. Philosophers following this course were met halfway by groups of scientists, mostly physicists and mathematicians, who in their own field had found themselves face to face with problems which traditionally belonged to philosophy. But since neither of these two groups was inclined to respect conventional boundaries, they joined forces and the result of their endeavors proved challenging to both philosophy and science. Various aspects and representative theses of this movement are known to-day as logical positivism, operationism, physicalism or scientific empiricism. For the movement as a whole, however, the term logical positivism is now becoming generally used. The present paper should be considered as a selective and partly historical survey of the methodological discussion in psychology from the standpoint of logical positivism. I. LOGICAL BEHAVIORISM'
At the time the logico-positivistic movement first gained momentum and influence outside the disciplines from which it For a bibliography see Stevens (16). 205
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started, psychology was still struggling against its metaphysical heritage, the earmark of its origin from traditional philosophy. At this state, Watsonian behaviorism was most consciously aware of the necessity of getting rid of this encumbrance, and this explains the sympathy logical positivists have always felt for behaviorism. There was no harm in the profession of this sympathy as long as the most liberal (and hence the most orthodox) application of Occam's razor was the operation most urgently needed by the nonphysical disciplines (biology, psychology, social sciences, in the following referred to as "biological sciences"). For these historical reasons also the term logical behaviorism, coined by Mempel (6) for the application of the logico-positivistic method to psychology, is amply justified. In the meantime, however, the scene has changed. To-day, every scientific psychology is practically "behavioristic," and in its methodological discussions psychology seems to have reached a complete understanding with logical positivism (Stevens (16)). But on the other hand, there is still some mistrust and uneasiness among psychologists and sociologists as to logical positivism. Therefore it might not be superfluous to state most expressedly just at this moment: Logical behaviorism does not identify itself either with physiological nor with any molar behaviorism, or with any special psychological theory at all. I t does not offer anything but logical criteria and formal methodological schemes and it is not able to take sides between various theoretical approaches within a science, provided that all these approaches comply with its purely formal requirements. The anachronistic prerogative of philosophy to decide ex cathedra among the various scientific theories has been completely and sincerely renounced. Sociological excursus. The resistance against logical positivism, wide-spread among scientists, especially in Europe, and based upon the suspicion that it is nothing but a kind of disguised, refined materialism, is a very interesting sociological fact in itself. But there are sufficient reasons to be found in history of ideologies for this ever-ready suspicion. As a matter of fact, it might be perfectly true that the value system behind logical
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positivism is psychologically and genetically akin to the materialistic attitude; but one must keep in mind that in this context "materialistic" is a purely sociologico-psychological term and has nothing to do with philosophical materialism. On the other hand, more conceptually-minded sociologists, specialising in the investigation of theoretical systems as such and their historical filiation, might be equally right in describing logical positivism as a "dialectic" outgrowth of the perennial antagonism between materialism and empiricism a t the one and idealism and rationalism at the other end of the scale of philosophic tempers. Both standpoints can be clearly distinguished in the system of logical positivism (formal logic and language analysis on the one side and scientific empiricism on the other). After all, logical positivists never claimed to be a parthenogenetic offspring of that absolute which they fight and deny so ardently. I t is true, however, that they did not give much attention to the clarification of their own historical position. But this in turn, though certainly no merit in itself, is perfectly understandable by the very nature of the scientific momentum which led to their achievements. The great enlightenment of the 18th century was not very historically-minded either. As a matter of fact, logical behaviorism, in spite of the connotations of the term, does not mean anything but the consistent application of I . The principles of operationism (empiricism) to the terms used in psychology and the "laws" connecting them, 2. Logical (language) analysis of the theoretical systems in which these terms and laws occur. In this formulation logical behaviorism seems to be almost unrestrictedly accepted by the psychology and sociology of to-day. Let us outline a few consequences of these two main aspects for psychology. If, by virtue of the clarification reached by psychology itself, these remarks seem rather obvious and self-explanatory, it is a symptom of the progressive integration of scientific thought and to the credit of both psychology and logical positivism.
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I . One should be most careful in substituting the termphysicalism for logical behaviorism. As outlined in a previous paper ( I ) in accordance with Feigl ( 2 , 3 ) , the term physicalism has two meanings. Only one of these is equivalent to the thesis of empiricism and operationism, while the second is merely a hypothesis and no essential part of the system of logical positivism. Physicalism in the first sense is sometimes formulated in this way: A scientific theory is meaningful if and only if operational relations between its constructs and those of physics can be established, i.e., if its system language can be "translated" into that of physics. For what that means in psychology, Tolrnan's book on purposive behavior with its farnous glossary is the already classical example. The physicalistic hypothesis (strict physicalism), however, claims that the terms and laws of any science can be "reduced" to and "derived" from the terms and laws of physics. Applied to psychology, this hypothesis is practically equivalent to the claim of physiological behaviorism, that psychology is a part of physiology. But this is, a t the present state of affairs, nothing but a prognosis and an opinion as to what line future research should preferably follow. Logical behaviorism will not be affected by the success or failure of such a program. 2. The anti-mentalistic and anti-introspectionistic thesis of early behaviorism was philosophically biased. Purified from ontological admixture, it yields two methodological problems, viz.: a. Whether a t all, and if so, in which systematical position, verbalizations should be used for the definition of psychological constructs, and b. Whether mentalistic terms like consciousness, intention, thought, and so forth, should be introduced into the system language (theory) of psychology. As soon as that became clear, the whole issue lost its interest entirely. Apparently it was just its concomitant metaphysical meaning which stirred up all those violent reactions a t that time. 3. Even if the thesis of strict physicalism is anticipated, it
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does not mean the discarding of all non-physical language levels. The choice of the system language is an entirely pragmatic decision. Also the hypothetical ideal physicist will not most suitably describe psychological and biological phenomena in terms of electrons and protons. Physics itself does not always push reduction as far as possible, and it is not probable that microphysical theories as such will ever be used to design or describe a locomotive. Only the experts can decide which language level suits best the purposes of their special science. To-day physicalism certainly carries the psychological danger of a too high level of aspiration for psychologists. This might be one more reason why strict physicalism, if explicitly stated, is frowned upon even by psychologists who implicitly adopt its thesis throughout the whole line of their thought. 4. Every-day language is a kind of primitive scientific system, constructed over the (individual) protocol. The protocol (of an individual) consists of sentences like "Now hungry", "Now here red circle". I t does not use the personal pronoun "I." Certain structural properties of the various (individual) protocols, e.g., their relation to the (intersubjective) system language of physics, the similarity they show in many respects, their spatiotemporal coherence, express themselves by the use of the personal pronouns, verbs such as "to think," "to feel" and nouns such as "mind," "wish," "reality." The traditional epistemological problems and statements induced by this linguistic use, among them all ontological questions, cannot even be formulated in any scientific language. If partial translation into a meaningful language is possible, they turn out most frequently to belong to the subject-matter of psychology. The gradual elaboration of the concept of behavior-object (Ding) by modern psychology is probably the most impressive example. The historical development from elementaristic stimulus-psychology through Gestalt theory to the investigations into the genesis and the structure of "behavior-objects" (Tolman and Brunswik (18)) and the stimulus equivalence (Hull (10)) covers all meaningful aspects of philosophical realism. In line with these cautious discriminations, also the workers in the field systematically
Problems of Psychology
closest to physiological reduction (reflexology) now distinguish most carefully between a model and an actual reduction (Hilgard ( 7 ) ) . 5. In an elaborate scientific theory the co-ordinating definitions are established only for a basic subclass of its constructs. The term basic in this statement should not be confounded with elementary. Syntactically "elementary" means the lowest level of the linguistic structure. Science, however, when discussing e.g., whether some isolated "atomistic" sensory data and their traces or perceptual wholes are elementary, uses the term in a strictly empirical, sometimes even phenomenological, and not in any methodological sense. Therefore reasons for establishing the correspondence between the very levels of these different kinds of "elementary" are of a merely pragmatic character and no methodological arguments against an "atomistic under-structure" can be derived from them (Hilgard (7)). Physics, at any rate, starts its theoretical construction deeply "below" the protocol, which in turn is a t the basis of all semantic coordinations. 11. HISTORICAL VS. SYSTEMATIC LAWS
The analysis of general terms like scientific law, theory, causality, as performed and systematized by logical positivism, has been abstracted from and elaborated in closest contact with the actual development of physics. This historical fact is often used as a starting point for criticism. Even those who admit that a suitable framework for the methodological problems of physics has been built up, argue sometimes against the straightforward and unqualified application of the same tools in the biological sciences. The historical source of this resistance is easy to trace. I t leads back to vitalistic ideas (Bergson) and that line of psychological thought, particularly deep-rooted in Germany (Dilthey, Spranger), which stresses the fundamental r61e of "understanding." The trend in psychology, however, is unmistakable. Pseudo-problems have almost completely disappeared in the methodological discussion, and certainly the logico-positivistic analysis has had its part in this development. But on the other hand logical positivists were not very much
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concerned with the special problems of the biological disciplines and often dealt with them in a rather summary way. Therefore there should be some rather general questions particular to these disciplines, which have not been given quite the attention they deserve. The issue connected with the antithesis of historical vs. systematic laws (theories, concepts and so forth) seems to belong to this group. In Lewin's recent work on theoretical psychology (11, 12, 13) the dichotomy is very strongly accentuated. But his arguments are often so closely interwoven with other considerations, that a few more general remarks might be justified, merely taking his terms as a point of departure. If one looks from outside a t modern psychology, the most striking traits are the strong tendency towards quantification, simultaneous efforts to eliminate "merely statistical" laws as much as possible, and the great emphasis laid upon conceptualization ("mathematization") and hypothetico-deductive derivation. I t is quite obvious that physics is the model science for those psychologists and there is ample evidence for that in their writings (Hull, Lewin). The term "systematic" is sometimes also used to characterize this trend, but as opposite to "historical" it has a more specific meaning. Also in this sense physics is regarded as representative for the systematic approach. Let us then consider the classical example of a physical law, Newton's formula: (S)
$xi
=f
X
I
, 2
,
,I
i = Z , Z > . . . n.
a system of differential equations connecting the (second) derivatives of the spatial coordinates of the masses (as functions of the time t) with the momentary positions of these masses. As far as the future is concerned, it is well known and exhaustively clarified (Frank (4)) as to how this typical form of the descriptive equation system has determined our ideas on causality (Laplace's world formula). In line with this clarification the teleological argument as against "mechanistic" causality is no longer used in scientific discussions to prove the particular character of the biological sciences as opposed to physics. As to the past a
212
Problems of Psychology
very obvious generalisation of (S), given below might prove useful to illustrate the meaning of a "historical law." Given a certain physical set-up, let (S) be the system needed for its description. FOPactual evaluation, certain measurements have to be carried out, to determine the constants and the initial values of the variables in these equations. Sometimes it is also necessary to consider the effects of the measuring observations themselves. Always, however, it is assumed that a) All the measurements necessary can be carried out "at present" and that one does not need the values of any of the variables a t any time point before t, and that b) The describing functions themselves do not change their "form" with the time. In physics everybody knows what b) means, but one should be certain that in a more general context this statement is rather vague and somewhat arbitrarily separated from a). Both assumptions are indispensable for the possibility and the usefulness of those set-ups called experiments in physics. Wherever laboratory set-ups are supposed to have the same systematic position within a science that experiments have in physics, it is silently presupposed that the investigated properties of the material conform at least approximately with a) and b). (Example: perception psychology). As a matter of fact, we see psychology immediately resorting to the method of case study, if those assumptions seem questionable. The stress which theoretical psychology also lays upon the systematic difference between case study and experimentation shows that it is well aware of its fundamental importance. I t should also be mentioned in this context, that the statement: "No experimentation is possible in history" has two meanings, viz., I ) no experimentally controllable sociological set-up in large can be arranged (problem of extrapolation), and 2 ) assumptions a) and b) are not sufEciently warranted. All this applies similarly to experimentation proper, as opposed to other methods of fact finding, in social psychology. The claim that psychology is a systematic science means, as far as I can see, that psychological constructs and psychological
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"3
laws connecting them, for which a) and b) are valid, can be found, and thit it will be possible to cover the whole field of psychology in such terms. In this statement the occurrence of the term "psychologicaP" is essential. For the thesis is not that after reduction of psychology to physiology, and, if necessary, a further reduction of the latter to physics, it will be possible to derive all the "historical" relations in psychology (and the social sciences) from the systematic laws of physics. The meaning is rather that this cai be done on the 1e;el of a '"enuinely psychological" theory. Although "genuinely psychological" is certainly no sharp concept, there will be hardly any misunderstanding as to what this expression intends to convey, and we shall not-try to define it. ~ t - i just s one of the results bf logico-positivistic analysis (theory of the unity of science) that there is little point in such attempts. Moreover the occurrence of (overt or covert) mentalistic -terms and the description of processes, where the individual is somehow involved as a whole, is still a practically sufficient criterion for a psychological theory. To make predictions about such molar behavior, Lewin starts out with thiequation
B being the behavioral unit, P the psychological person and E the psychological environment. Again the adjective psychological is essential and marks the first step necessary to obtain systematic laws, for the reaction of the "same" individual to the same physical environment depends quite obviously upon the individual's history. A rat in a maze behaves differently after starvation periods of different lengths and according to its previously acquired "knowledge" about what he is going to find in the goal-box. Moreover, the person is a very complex variable and there is, even with rats, the problem of individual differences. Consequently the systematical approach has to start from a set of "intervening variables" (Tolman (17)) of a purely inferential character. Each of these variables might be operationally related to the person as well as to the environment. This is expressed by integrating the variables at the right side of (L) into
Problems of Psychology
the concept of life space. The probable interdependence of these variables is expressed by the term $eld, which thus is entirely identical with the term "Gestalt" in its meaning as "system of interaction" (Grelling-Oppenheim (5)). The claim of the systematic approach then is: al) Methods to determine a t present the "structure and dynamics of the life space" (to measure all the constants and the present values of those to-be-defined variables) can be devised. bl) There are functions f of a given, unchanging form, by means of which the behavior B can be derived from those measurements. In view of the peculiarities of the psychological material it might not be superfluous to isolate one more self-explanatory assumption : cl) All the measurements mentioned in al) can be carried out independently from the actual occurrence of B, the behavior to be predicted, and the state of the field is not essentially affected by these manipulations. Two more remarks should rule out any possible misunderstanding: I ) The determination of the values of variables a t earlier time points, e.g., by asking a human subject, is still an essentially historical procedure, and if these values actually occur in the describing equations, the law is a historical law. Otherwise the whole issue would be an entirely trivial question of terminology. 2) There is no objection from the systematic standpoint against using historical methods to determine present states, if they are technically preferable, provided only that there are also systematic methods to do it. T o starve a rat for a certain time might be an easier method to determine its present state of hunger than the carrying out of certain physiological measurements to the same effect. The concept of a historical law, on the other hand, involves the dependence of the descriptive functions not only upon the
G. Bergmann
2x5
values of the variables a t the given time point t, but also on their values a t a (finite or infinite) number of previous time points (or intervals) tl, tz,. .. Here it should be mentioned, that the term "systematic" seems to be used sometimes also to eliminate an bbvious misinterpretation of the term "historical," viz.: No reasonable attempt would try to tie the present values to certain absolute time points. T o say the same thing in a more vague but more suggestive language, it is not the empty time per se, but rather its content, the temporal development of the process which is thought of as influencing the present. The sirn~lestinter~retationof this idea as to the variables and the 1 form of the laws by a mathematical model then would be: a%)The values to be substituted into the empty places of the functions f, to make the evaluation a t the time point t possible are not the momentary values of the variables XI, x2, . x,, but values derived by certain operations from the values of (all) the variables during time intervals preceding t. A very general expression for these to-befilled-in values would be:
.
I
Substituting this, e.g., in a system like (S), one obtains
This is an integro-differential equation of the type investigated by Volterra. I t would be a matlrematical model of a historical law, in which the idea of the constancy of the functional relation (assumption b)) is given a concrete interpretation by the form of the functions f. Let us add a few remarks concerning (H): I . By the occurrence of earlier values of the variables any science using historical laws is faced with the methodological problem of defining the criteria of historical truth. 2. The function (p in (T) covers a wide range of possible structures. The fact, for instance, that the events previous to a
Problems of Psychology
certain time point tl have no effect within the present constellation, would be expressed by p = o in the time interval from the lower limit to ti. 3. There are no historical laws of the form (H) in physics of to-day. Therefore the question comes up as to whether the occurrence of historical laws is compatible with the hypothesis of strict physicalism. Of course, one could always say that on the way to actual and complete physicalisation one would discover "physical" laws of a still unknown type. Applied to biology, this is about the empirical meaning of vitalism. But physicalists would not like this answer, and it does not seem that they would have to resort to it. At least there is no simple mathematical reason, why those molar combinations of solutions of systems (S), which correspond to the terms of the biological sciences ( I ) should not in reasonable approximation fulfill equations of the type (H). On a more or less speculative level socalled "trace" theories seem to anticipate this expectation. Although in the recent methodological discussions psychoanalysis has not yet been given quite the amount of attention one would expect after the breakdown of the antimentalistic prejudice (p. 208), the various tendencies towards a rapprochement are beginning to make themselves felt (Rosenzweig (15)). At any rate "behaviorization" and "experimental proof" of psychoanalysis seem to be accepted as a realistic and even desirable program by so-called academic psychology. Certainly direct operational links for a sufficiently large subclass of psychoanalytic concepts should be most carefully established. The very fact that many mentalistic terms, as consciousness, wish, memory, ego, had to be stratified and modified in the psychoanalytic theory, suggests that such an attempt would be of more than methodological interest. Moreover it will help to bridge what is still left of the original gap between psychoanalysis and the rest of psychology. But such a translation, if it is not to destroy the finer structure of the theory, might prove to be a very hard For a bibliography see Rosenzweig ( 1 5 ) .
G. Bergmann
job; a t any rate it is far beyond the scope and the ambition of the present paper. A few remarks, however, will be ventured. I . There are some parts of the theory which can be subjected to an experimental test. The hypnotic experiments, arranged to demonstrate the general "knowledge" of the symbols, cannot fail to be mentioned once more in this context. I t is also possible to furnish statistical evidence for the amount of correlation actually obtaining between personality traits, for which the psychoanalytic theory predicts such an interdependence. The same might hold true for correlations between personality traits and biographical facts, and there seem to be still many other ingenious ways to use psychoanalytical ideas for experimental explorations in personality (Murray (14)). But psychoanalysis is essentially also a historical theory. Because of this fact it is not easy to see, how experimental verification can be extended over certain limits. Therefore it might not only be historical and emotional antagonism that makes analysts rather cautious in view of a too high-spirited eclectic optimism. 2. By giving very neat and strictly empirical definitions of terms as libido, ambivalence, sublimation, aggression, and by eliminating all "unscientific" pictures and analogies from the relations describing the various possibilities of their functional and genetic interdependence, one might build a marvelous airplane, but still there would be no airports providing firm landing ground. For psychoanalysis claims (and there is every possible evidence that this claim is consistent with the whole structure of the theory): To make any concrete prediction about an individual's behavior (to bring about any therapeutic effect) one must a) Determine the special kind of linkages (drive history, history of ego and superego formation) which have taken place with the individual in question, and that b) The only procedure by which this can be achieved, is the analytical treatment itself. Thus the "protocol" from which any meaningful operational approach to psychoanalysis will have to start, is not the writings
218
Problems of Psychology
of the analysts, but a sufficient number of phonographic records of real analyses. 3. I t is the privilege of historical theories in the biological sciences to give us the stimulating experience and the pragmatically invaluable help of "understanding" by a lucid interpretation of the past. But for a historical theory also the crucial test is the possibility of predictions. This implies for instance for history in the usual sociological meaning of this term: A scientific theory of history must be able to answer questions of the following type: "Given a concrete historical situation, which changes can be effected and by which means?." This is a point to be made before any question of reliability. If an approach to history does not provide such concrete answers, its claim to be a scientific theory should be dismissed without a hearing. What now is the result, if one applies this criterion to the historical theory of psychoanalysis? Here, as in any other clinical field, the main question seems to be, whether successful cures are possible and how to perform them. If there is sufficient evidence that healings a t a rate exceeding chance are being obtained, and if the reports of the analysts about what they are doing with their patients in camera caritatis are true, the objection of subjectivity will need a careful rewording. The therapeutic effect of a treatment can be tested by objective methods and the possible use of phonographic records has already been mentioned. But what is the empirical procedure to demonstrate the subjectivity, to unmask the working of the individual analyst's suggestive power as the true mechanism ? Apparently one would have to have the same patient treated by two different analysts successively. How to do that, if the first has been successful? And if he has not been, what would it prove? Writing about psychoanalysis, however, it might be wise to imitate the analysts' habit of anticipating counterarguments. Therefore it shall be expressedly mentioned, that no proselytic zeal blinds me against the peculiar problems involved in this phenomenon of the "subjectivity of the psychoanalytic method." But it seems to be a methodological issue within, rather than a case against, psychoanalysis. 4. Let us finally mention another formal criterion any historical
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theory must fulfill. Both, the statesman unleashing a propaganda drive and the analyst who starts a cure are going to change the "natural course of events." Consequently their theories must be constructed in a way, which accounts for the effect of this interference, otherwise the theory is not closed. As to psychoanalysis, a detailed explanation of the mechanism of the treatment is a rather carefully integrated part of the theory. Thus this formal requirement is fulfilled. There is a certain analogy between this phenomenon of closure of a historical theory and the necessity of considering the effect of the observations in an experimental discipline.
State University of Iowa BIBLIOGRAPHY Bergmann, G. On Physicalistic Models of Nonphysical Terms. This issue. H. Logical Analysis of the Psycho-physical Problem. Philos. of Science, '934, 1, 420-445. 3. Feigl, H. Unity of Science and Unitary Science. Journal of Unified Science, 1939. 4. Frank, Ph. Das Kausalgesetz und seine Grenzen. Wien, J. Springer, 1932. 5. Grelling, K. u. Oppenheim, P. Der Gestaltbegriff im Licht der neuen Logik. Erkenntnis, 1938, 7, 211-224. 6. Hempel, C. G. Analyse logique de la psychologie. Rev. Synthese, 1935, TO, 27-42. 7. Hilgard, E. R. The Relationship between the Conditioned Response and Conventional Learning Experiment. Psychol. Bull., 1937, 34, 61-102. 8. Hull, C. L. The Conflicting Psychologies of Learning-a Way Out. Psychol. Rev., '935,429 497-5'6. g. Hull, C. L. Mind, Mechanism, and Adaptive Behavior. Psychol. Rev., 1937, 44, 1-32. 10. Hull, C. L. The Problem of Stimulus Equivalence in Behavior Theory. Psychol. Rev., 1939,46,9-30. 11. Lewin, K. Principles of Topological Psychology. New York, McGraw-Hill, 1936. 12. Lewin, K. Psychoanalysis and Topological Psychology. Bull. Menninger Clin.. 1937, I, 202-211. 13. Lewin, K. The Conceptual Representation and the Measurement of Psychological Forces. Contrib. Psychol. Theory, I, 4. Duke University Press, 1938. 14. Murray, H. A. Explorations in Personality. New York, Oxford University Press, 1938. 15. Rosenzweig, S. The Experimental Study of Psychoanalytic Concepts. Character and Personality, 1937, 6, 61-70. 16. Stevens, S. S. Psychology and the Science of Science. Psychol. Bull., 1939, 36, 221-263. 17. Tolman, E. C. The Determiners of Behavior a t a Choice Point. Psychol. Rev., '938,45,'-41. 18. Tolman, E. C. and Brunswik, E. The Organism and the Causal Texture of the Environment. Psychol. Rev., 1935,42,43-77. I.
2. Feigl,
