Notes and Discussions

<<The Subjective Element in Scientific Discovery: Popper versus ’Traditional Epistemology’>>

by Paul TIBBETTS*

The explanation [of scientific change and problem solving] must, in the final analysis, be psychological or sociologi- cal. It must, that is, be a description of a value system, an ideology, together with an analysis of the institutions through which that system is transmitted and enforced. Thomas Kuhn (1) Traditional epistemology with its con- centration . . . on knowledge in the sub- jective sense, is irrelevant to the study of scientific knowledge.

Karl Popper (2)

This paper examines Popper’s distinction between objective and subjective knowledge claims, together with some recent proposals by Lehrer and Herman regarding knowledge, belief and inference. It is argued that for Popper the pro- posals of Lehrer and Harman are largely exercises in subjective epistemology and as such irrelevant to our understanding of knowledge and discovery in scientific contexts. For Lehrer and Harman, on the contrary, apart from an analysis of belief and inference the growth of human knowledge and the justification of knowledge claims in general would be incomprehensible if not conceptually impossible. A discussion then follows of Popper’s argument that subjective episte- mologists have mistakenly equated the ordinary sense of “I believe” and “I know” with knowledge in the objective or scientific sense and consequently have mis- construed the entire process of problem solving in scientific contexts. The paper concludes that Popper has himself ignored one of the central factors in much of scientific discovery, a factor which subjective epistemology has rightly stressed, namely, the role of gestalt shifts in conceptual change.

* Department of Philosophy University of Dayton, Dayton, Ohio 45469.

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(I) According to Popper, subjective knowledge (or SK) has three characteris- tics: first, SK is knowledge in the ordinary pre-scientific usage of the expression “I know”; secondly, SK is not independent of someone’s belief states, thought pro- cesses, or dispositions to assent or act; lastly, SK requires a state of mind or con- sciousness. In other words, SK - unlike objective knowledge (OK) - requires a knower or knowing subject. (3) Given these characteristics, Lehrer’s account of knowledge is clearly an instance of knowledge in its subjective sense. For example, according to Lehrer the justification of a proposition is synonymous with the coherence of that proposition within a system of beliefs, which Lehrer refers to as the “doxastic system of a man.” (4) Continuing, within a “suitably corrected doxas- tic system,” subjective conviction together with the entailment relation between one belief and another are sufficient to provide complete justification. As Lehrer remarks,

We need not seek any guarantee for the truth of what we believe, nor need we appeal to explanatory relations among beliefs to provide a justification. Our set of beliefs can offer complete justification of deserving beliefs among its membership without any external support or sustenance. The be- liefs a man has make up a self-sufficient epistemic community. (5)

In “Evidence, Meaning and Conceptual Change” (6), Lehrer argues that even the selection of evidence is relative to the subjective probabilities a person is pre- pared to assign a set of proposed evidence statements. In addition, the subjective probabilities we employ in the rational selection of evidence are not fixed but are relative to our beliefs and to circumstances (e. g., attitude, social context, back- ground knowledge, etc.).

Whatever influences men as they try to shape a conception of the universe satisfying their desires for coherence, simplicity, completeness and so forth may alter their subjective probabilities. Thus, a statement that is more probable than its strongest competitor at one time may subsequently under- go a downward turn in probability and no longer compete favorably. It will then be rejected as evidence. (7)

It should be noted that Lehrer does attempt to differentiate an arbitrary as against a rational assignment of subjective probability by claiming that the latter must “preserve the appropriate kind of relevance between statements when there is agreement among those who search for truth concerning relevance.” (8) Conse- quently, the criteria Lehrer employs in the assignment of subjective probabilities in the rational selection of evidence are (i) the coherence and consistency of the evidence-candidate with one’s doxastic system of belief, and (ii) intersubjective agreement concerning relevance. (9) (Lehrer does recognize that in this matter of social consensus and intersubjective agreement, some inquirers’ assignments of subjective probabilities and relevance do count for more. In a paper entitled “Rationality in Science and Society: A Consensual Theory” (lo), Lehrer spells out in some detail how the “expert and sagacious” in a community are to be defined. In spite of Lehrer’s intersubjectivity requirement, his position would still be label- ed as subjective by Popper given the ‘coherence of belief’ emphasis.)

Harman has similarly defended what Popper would label a subjective episte- mology, particularly Harman’s discussion of knowledge and justification within the context of a person’s belief system. Though Harman’s position is not as expli-

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citly nor as thoroughly an instance of SK as is Lehrer’s discussion, it would also be classed as subjective in Popper’s sense. In his analysis of inductive inference, for example, Harman argues that such inference ‘Lmust be assessed with respect to everything one believes.” Accordingly, a rule of inductive inference is for Harman a “rule of acceptance,” since it informs us as to what beliefs can be accepted or rejected given competing beliefs. As he writes,

An accurate conception of inductive inference takes it to be a way of modi- fying what we believe by addition and subtraction of beliefs. Our “pre- mises’’ are all our antecedent beliefs; our “conclusion” is our total resulting view . . . Induction is an attempt to increase the explanatory coherence of our view, making it more complete, less ad hoc, more plausible. At the same time we are conservative. We seek to minimize change. We attempt to make the least change in our antecedent view that will maximize explana- tory coherence. (1 1)

(11) Along with Descartes, Hume, Kant and Russell, Lehrer and Harman would therefore be classed by Popper as “belief philosophers,” given their com- mon concern with the origins and grounds of human subjective belief. For Popper, on the other hand, what is central to scientific knowledge are theories, arguments and counterarguments, not belief-states, subjective betting preferences (Lehrer), or doxastic systems. As Popper writes,

what is relevant for epistemology is the study of scientific problems and problem situations, of scientific conjectures, . . . of scientific discussions, and of the role played by evidence in arguments; and therefore of scientific journals and books, and of experiments and their evaluation.. . (12)

In opposition to SK advocates, then, Popper claims that scientists are not at all concerned with whether they “believe” or “know” their conjectures in the subjec- tive sense. What they are interested in are problems, conjectures and attempts at refutation. The only role subjective belief plays concerns what is or is not a pro- mising conjecture concerning the enlargement and growth of 0 . K In contrast then with a subjective epistemology, Popper is therefore less concerned with the psy- chological process or production which generates theories, problems, etc. but rather with the products and results of this process. By focusing on the circle of belief, expected utility, inferential processes, and so on, philosophers have in effect shifted from questions of OK to questions of psychology or even sociology. For Popper, knowledge-as-process and knowledge-as-product are clearly different and are not to be collapsed into one another.

This fascination with the knowing process and with questions of belief, with the possibility of being mistaken, the problems of certainty and incorrigibility, has driven many a subjective epistemologist into scepticism. The absurdity of such an approach for Popper would be epitomized by an Unger and the claim that

no one is ever justified or at all reasonable in anything. In particular no one will be justified or at all reasonable in believing anything . . . [The] scepti- cal conclusion we now seek to yield may be put like this: Everybody is always ignorant of everything. (13)

For Popper this is a logical consequence of any epistemology which focuses on the subjective activity of knowing, believing and doubting. In reaction to this

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approach, Popper has argued that “doubting” and “believing” are neither neces- sary nor sufficient for the growth of knowledge since “we may doubt without criti- cizing, and criticize without doubting.” (14) Accordingly, subjective epistemolo- gists such as Lehrer, Harman, and Unger are for Popper conceptually unable to understand scientific knowledge and problem solving, which (to repeat from above) are less concerned with the psychological processes at work in scientists’ heads than with the products of this process (theories, conjectures, refutations, etc.).

(111) It should be clear by now that Popper’s assault on SK and on subjective epistemology in general is quite consistent with and indeed entailed by his particu- lar interpretation of the nature of scientific knowledge and inquiry. The question remaining is whether Popper’s position can take into account creative insight, dis- covery, and serendipity in science for these would clearly qualify as subjective phenomena given Popper’s position above. Granted, the conjectures and hypothe- ses which result from these phenomena are subject to refutation and amendment. However, it is not the product but the process or act of insight and discovery itself which I am concerned with. In my opinion, a subjective epistemology or even a cognitive psychology would appear more able to account for these phenomena than anything suggested by Popper. Possibly in anticipation of this criticism, Pop- per wrote in the Logic of Scientific Discovery (or LSD) that “the logic of scientific discovery should be identified with the theory of scientific method” (15) and the theory of method in turn is concerned with the choice between competing method- ologies. Ironically, scientific discovery per se receives little discussion in the LSD. Even if we look in Popper’s other writings concerning scientific inquiry we find Popper consistently adhering to the view taken in LSD of simply equating scientif- ic discovery with questions of methodology rather than with questions of psychol- ogical processes.

In “Logic of Discovery or Psychology of Research?” Kuhn suggests that [When Popper] rejects ‘the psychology of knowledge’, Sir Karl’s explicit concern is only to deny the methodological relevance of an individual’s source of inspiration or of an individual’s sense of certainty. With that much I cannot disagree. It is, however, a long step from the rejection of the psychological idiosyncrasies of an individual to the rejection of the common elements induced by nurture and training in the psychological make-up of the licensed membership of a scientific group. One need not be dismissed with the other. (16)

I disagree with Kuhn on this matter. I think that Popper is clearly rejecting the methodological relevance of “an individual’s source of inspiration,” regardless of whether that individual is a member of a scientific community or not. Even Kuhn would admit that there is no guarantee that the inspirations or “sense of certainty” of even a licensed member of a scientific community will possess methodological relevance. Nor is there any guarantee that individuals outside the licensed mem- bership will inevitably fail to achieve significant and relevant insights. Besides, there is always the problem of determining what constitutes the “licensed member- ship” of a scientific community. I seriously doubt whether Kuhn’s line of argu- ment, however interesting it might be on other grounds, is sufficient to induce Popper to reconsider the “psychology of the individual” in discussions concerning

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scientific discovery and the growth of knowledge. In fact, Popper’s reply to Kuhn is to say, “Of course, the central issue between Kuhn and myself is given in Kuhn’s title, ‘Logic of Discovery or Psychology of Research?’ My answer is that . . . the psychological world of the scientist is almost completely dependent on the . . . world of scientific theories and problems.’’ (17) Popper thus misses Kuhn’s point entirely.

The question is whether any other considerations would induce Popper to re- examine his assumptions regarding psychological processes. In the remainder of this paper I will suggest one such consideration: the centrality of gestalt shifts in much scientific discovery, that is, the conceptual significance of alternative (and frequently conflicting) patterns of organization and explanation. First, there are the various perceptual gestalt shifts such as the Necker-cube reversal, the bear on the tree, and rabbit-duck type examples in general. Then there are those gestalt shifts that occur on the conceptualftheoretical level; e. g., the shift from a Ptole- maic to a Copernican interpretation of planetary movement, or from an Aristo- telian to a Galilean account of projectile motion. As Hanson writes,

You see a bird, I see an antelope; the physicist sees an X-ray tube, the child a complicated lamp bulb; the microscopist sees coelenterate mesoglea, his new student sees only a gooey, formless stuff. Tycho and Simplicius see a mobile sun, Kepler and Galileo see a static sun. ‘That researches sometimes do not appreciate data in the same way is a serious matter. It is important to realize, however, that sorting out differ- ences about data, evidence, observation, may require more than simply ges- turing at observable objects. It may require a comprehensive reappraisal of one’s subject matter. (18)

Along with Hanson, Popper also rejects a naive realist account of perception. This is evident in his paper, “The Bucket and the Searchlight: Two Theories of Knowledge.”

In science it is observation rather than perception which plays the decisive part. But observation is a process in which we play an intensely active part. An observation is a perception, but one which is planned and prepared. We do not ‘have’ an observation . , . but we ‘make’ an observation . . . An observation is always preceeded by a particular interest, a question, or a problem. At every instant of our pre-scientific or scientific development we are living in the centre of what I usually call a ‘horizon of expectations’. By this I mean the sum total of our expectations, whether these are subcons- cious or conscious . . . The horizon of expectations plays the part of a frame of reference: only their setting in this frame confers meaning or significance on our experiences, actions, and observations. (1 9)

Popper does admit, then, that observation in science is inseparable from inter- pretative, conjectural and related “cognitive processes.’’ And given that inquiry in science also frequently involves gestalt-like shifts in perceptual/conceptual orienta- tion, we must conclude that (i) either Popper is inconsistent in ignoring the psy- chological process which generates new problems, theories, and conjectures, or (ii) he is simply working with an oversimplified model of observation and discovery in

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science, or (iii) perhaps both (i) and (ii). Interestingly, in the 200-odd pages of detailed response to his critics in the Library of Living Philosophers’ volume on Popper, the expression “Gestalt switch” only occurs in two places in his reply, and neither of these in the context of scientific discovery!

One final point. Recognition of the role played by cognitive processes in scien- tific inquiry need not in my opinion commit us to either the assumptions or con- clusions of “belief philosophers” such as Lehrer, Harman and Unger concerning belief-states, doxastic systems, or epistemological scepticism. On the other hand, “belief philosophers” have by no means in my opinion exhausted their contribu- tion to our understanding of such cognitive processes as inferring, believing, doubting, or knowing. To assume as does Popper that such processes are irrelevant to the study of scientific knowledge per se is to adopt a highly tenuous claim, a claim which in Popper’s case rests on two distinctions. First, a distinction between cognitive processes as such (i. e., SK) as against the products of such processes (OK). Secondly, there is the attempted distinction by Popper between the growth of knowledge in scientific as contrasted with non-scientific, everyday experience contexts. Though this paper has focused on the first of these two distinctions, it is highly debatable whether in the final analysis either of these distinctions is empiri- cally warranted or methodologically sound.

REFERENCES

1. T. Kuhn, “Logic of Discovery or Psychology of Research?” in P. A. Schilpp (ed.) The Philosophy of Karl Popper (LaSalle: Open Court, 1974), vol. 11, p. 814.

2. K. Popper, “Epistemology Without a Knowing Subject,” in his Objective Knowl- edge (New York: Oxford University Press, 1972), p. 111.

3. Ibid., pp. 108-109. 4. K. Lehrer, Knowledge (New York: Oxford University Press, 1974), pp. 189. 5. Ibid., pp. 185-186. 6. K. Lehrer, “Evidence, Meaning and Conceptual Change: A Subjective Ap-

proach,” in G. Pearce and P. Maynard (eds.) Conceptual Change (Boston: D. Reidel, 1973), pp. 94-122.

7. Ibid., p. 111. 8. Ibid., p. 118. 9. Ibid., p. 120.

10. K. Lehrer, “Rationality in Science and Society: A Consensual Approach,” in G. Ryle (ed.) Contemporary Aspects of Philosophy (London: Oriel Press, 1975), p. 159.

11. G. Harman, Thought (Princeton Univ. Press, 1973), p. 159. 12. K. Popper, “Epistemology Without a Knowing Subject,” op. cit., p. 111. 13. P. Unger, Zgnorance (New York: Oxford University Press, 1975) p. 1 and pp. 93-94. 14. K. Popper, “Epistemology Without a Knowing Subject,” op. cit., p. 141. 15. The Logic of Scientific Discovery (New York: Science Editions, 1959), p. 49. 16. T. Kuhn, “Logic of Discovery or Psychology of Research?” op. cit., pp. 815-816. 17. K. Popper, “Replies to My Critics,” in P. A. Schilpp (ed.) The Philosophy of Karl

Popper, op. cit., vol. 11, p. 148. 18. N. Hanson, Patterns of Discovery (New York: Cambridge University Press, 1958),

p. 17 and p. 19. 19. K. Popper, “The Bucket and the Searchlight: Two Theories of Knowledge,” in his

Objective Knowledge, op. cit., pp. 342-345.

Dialectica Vol. 34, No 2 (1980)