13
ABDUCTION, PRAGMATISM, AND
THE SCIENTIFIC IMAGINATION[(]
H.G. Callaway
Peirce claims in his Lectures on Pragmatism [CP 5.196] that “If you carefully consider the question of pragmatism you will see that it is nothing else than the question of the logic of abduction;” and further “no effect of pragmatism which is consequent upon its effect on abduction can go to show that pragmatism is anything more than a doctrine concerning the logic of abduction.” Plausibly, there is, at best, a quasi-logic of abduction, which properly issues in our best means for the methodological evaluation and ordering of (yet untested) hypotheses or theories. There is always a range of explanatory innovations that may be proposed, from more conservative to less conservative; and it is important, in light of what Peirce has to say on the relation of abduction to pragmatism, that in ruling out “wild guessing,” attention be initially directed to more conservative proposals. Still conservativism, which we might understand in terms of Peircean continuity, is sometimes justly sacrificed for greater comprehension or overall simplicity of approach. This paper explores the relationships among Peircean abduction and pragmatism, the “theoretical virtues” approach to the evaluation of hypotheses, and contextual constraint on the scientific imagination.
1. Background for Peircean Abduction
An element of the historical background of Peirce on abduction can plausibly be traced to the Coleridge-Emersonian contrast between “imagination” and “fancy,” which explicates or sharpens the ordinary usage and dictionary definition of the English word “imagination.” Emerson contrasts imagination and fancy vividly in his Letters and Social Aims (1875):
Imagination is central; fancy superficial. Fancy relates to surface, in which a great part of life lies. The lover is rightly said to fancy the hair, eyes, complexion of the maid. Fancy is a willful imagination, a spontaneous act; fancy, a play as with dolls and puppets which we chose to call men and women; imagination, a perception and affirming of a real relation between a thought and some material fact. Fancy amuses; imagination expands and exalts us. Imagination uses an organic classification. Fancy joins by accidental resemblance, surprises and amuses the idle, but is silent in the presence of great passion and action. Fancy aggregates; imagination animates. Fancy is related to color; imagination to form. Fancy paints; imagination sculptures.[1]
In effect, flights of fancy are contrasted with the constructive, cognitively oriented imagination. “Imagination is central,” says Emerson, while “fancy is a willful imagination” and sometimes “a play as with dolls and puppets which we chose to call men and women.” Imagination, in contrast, always relates thought to “some material fact,” it is “a perception,” according to Emerson, a matter of at least taking something to be true, since we do not affirm the perception that so and so, and at the same time call it an illusion, too. “Imagination uses an organic classification,” says Emerson, while fancy “joins by accidental resemblances” and “is silent in the presence of action.” From a philosophical perspective, as contrasted with that of literature as purely aesthetic interest, Emerson’s fully developed conception of imagination is a refinement of the common-sense notion which eliminates or sharply separates the element of willful fantasy, and it is a significant precursor of C.S. Peirce on abduction. The point is connected with what I have called Emerson’s anti-nominalism.
Emerson stresses the claim that thought, as cognitive accomplishment, makes us free, partly by extending human control over nature; and, he equally emphasizes normative observation of laws of thought. “For,” he says, “thought “ too must act according to eternal laws, and all that is willful and fantastic in it is in opposition to its fundamental essence.”[2] From this one may safely infer, that the “organic classification” which imagination is to employ corresponds to those concepts required for and identified in ascertained law of nature, including, in Emerson, natural moral laws. So long as we are subject to stubborn circumstance, and have some need to expand our freedom and power, there is always a prospective “higher law,” which we have yet to observe, recognize, or institute. It is this kind of point which made of Emerson both a student of the sciences and an abolitionist.
Central to Peircean abduction is the idea that we need some deeper understanding of the origin of reasonable hypotheses, or educated guesswork,[3] in contrast with wild or fantastic guessing, and equally, we have need for comparative evaluation of hypotheses at a point short of their confirmation or refutation by reference to predictions. Peirce proposed to investigate the logic of abduction, though to hold that there is a logic of abduction makes a strong claim on Peircean instinct, existing knowledge, or accepted theory to guide the evaluation of new hypotheses. Peirce claimed, in a very suggestive formulation, that the question of pragmatism is the question of abduction, and the claim is of special interest for our studies of American philosophy, if we are concerned to resist the tendency of the current revival of pragmatism to reduce to a polite, anti-intellectualism of pleasing conversation or a “vulgar pragmatism” of the predominance of the numbers of voices or of institutional rigidities. For Peirce, the relation of pragmatism to abduction turns on the question of the conceivable practical effects of an hypothesis. Once confirmed and established by scientific inquiry, it is clear that our erstwhile hypothesis may indeed embody practical effects. Yet the more interesting question is to see how consideration of conceivable methodological consequences of alternative hypotheses may help direct attention among them, prior to confirmation or disconfirmation of competing predictions. We want to understand how accepted laws or generalizations and concepts of a given field of inquiry may structure and constrain the formation and initial plausibility of new hypotheses in answer to outstanding problems of the field. The question of pragmatism is the question of abduction, wrote Charles Sanders Peirce, and I modify this here to say that one question of pragmatism is the question of the reasonability of evaluating (untested) hypothesis by reference to the range of scientific theory and results which we seek to correct or modify: there being “better and worse” among untested hypotheses.
The point stands in some tension with William James’s dictum that “on pragmatic principles we cannot reject any hypothesis if consequences useful to life flow from it.”[4] This Jamesian dictum finds at least this much support in Peirce’s Lectures on Pragmatism, where he wrote that “if pragmatism is the doctrine that every conception is a conception of conceivable practical effects, it makes conception reach far beyond the practical. It allows any flight of imagination, provided this imagination ultimately alights upon a possible practical effect; and thus many hypotheses may seem at first glance to be excluded by the pragmatical maxim that are not really so excluded.”[5] Arguably, Peirce means to include hypotheses not of a narrow practical sort, while James aims to include comforting non-empirical generalizations. We expect that is, in spite of the similar formulations, that for James and Peirce, the range of “live options” will differ.
The theme of a better and worse to untested hypotheses elaborates meliorism regarding the growth of knowledge. Viewing methodology as guiding the practice of inquiry and science, we naturally view initial evaluation of hypotheses as part of this practice. Many remain skeptical of Peirce’s conception of truth as the opinion fated to be accepted at the end of inquiry. No particular statements are ultimately fated to be accepted independent of our practice and our choice of methods. But putting that question aside, and understanding the meaning of accepted doctrine in terms of conceivable practical effects, if the question of pragmatism is the question of abduction, then pragmatism requires that accepted scientific doctrine have some tendency, a propensity in some degree, to expand and transform into a fuller account—in the direction of truth. For we expect that our new hypothesis will have significant explanatory and predictive power, not in isolation, but only as logically combined with the body of knowledge which it would be used to modify.
2. Scientific Meliorism and Popper’s “Bold Conjectures”
The topic of abduction is not one always well beloved by empiricist. Abduction is one area of Peirce’s thought were the charge of “psychologism” and/or subjectivism seems to regularly arise. Most often this presupposes, in the philosophy of science at least, a stronger version of the distinction between the “context of discovery” and the “context of justification.” The argument may be made that it makes no difference how we come by our hypotheses—which I doubt—, what matters is only whether or not we can assemble sufficient evidence. From that perspective, the idea of a “logic of abduction” has little appeal, and one simply substitutes talk of, say, “educated guesswork.” In contrast, I will argue for an objective basis for reasoned preferences among untested hypotheses, and emphasize that even on a diminished basis, if there is strictly no logic of abduction, still we need some account of the difference between reasonable hypothesis and wild guessing.
It seems obvious that not just any hypothesis will be as good as any other in the context of a particular scientific report. Instead, an eligible hypothesis must be strongly relevant to the results reported and have a clear connection to the subject-matter and the particular problems addressed in prior sections of the paper. We expect, too, that there will be some strong relevancy to the methods employed, or usually employed, in the investigation of similar problems. Lastly, the suggested hypothesis would have to make some plausible contribution to the possible interpretation of the results reported in the paper. The suggestion of possible further hypotheses belongs in the “Discussion” section of a scientific paper, because it indicates something of the fruitfulness of the results and/or methods employed as these are connected to the problem under investigation. If the particular results suggest no further studies, then they would seem to be a sort of dead end. But if particular methods and results suggest a further hypothesis, then we have a better idea of how to continue a particular line of inquiry. Seeking an objective basis for preference among untested hypotheses, one may hope to avoid not merely subjectivism but also over-emphasis on consensus and externally motivated consensus seeking. Likewise, if we have a way of ordering hypotheses independent of new empirical tests, then we are in a better position to resist the influence of money, media, and political or institutional rigidities as these may affect the weighting of alternative hypotheses and proposals for research.
The notion of abduction goes missing in Karl Popper’s writings, and this in spite of his generally positive relationship to Peirce. Popper usually speaks of “conjecture” where others might be inclined to speak of abduction, or “inference to the best explanation.” Plausibly, an initial comparative evaluation of hypotheses cannot be completely separated from the ways in which they are tested or might be tested, so that Peircean abduction, deduction and induction tend to combine in many contexts; and that is to be expected, even welcomed. That a given scientific proposal is testable, or at least prospectively testable, certainly lends it higher standing.
We find a similar combination in Popper, given the prevalence of the phrase “conjecture and refutation.” Beyond that, there are some suggestions of a quasi-logic of abduction (general grounds for preference among as yet untested conjectures) in Popper’s writings. In Objective Knowledge, Popper briefly characterizes his conception of conjecture in relation to “the method of science”: “The method of science,” he says, “is the method of bold conjectures and ingenious and severe attempts to refute them;” and “a bold conjecture is a theory with great content—greater at any rate than the theory which, we are hoping, will be superseded by it.” Popper continues:
That our conjectures should be bold follows immediately from what I have said about the aim of science and the approach to truth: boldness, or great content, is linked with great truth content; for this reason, the falsity content can at first be ignored.[6]
For Popper, a bold conjecture is to be preferred to a less bold conjecture, or at least he wants a bolder conjecture, a theory of greater content, than what is contained in the theory we hope to supplant. Popper’s position stands in considerable tension with a preference for more conservative and modest hypotheses which tend more to projections of pre-existing theory and results.[7] “Our conjectures should be bold,” says Popper. “Great content” or greater content is to be preferred. For Popper, if we want a comparative evaluation of two new theories, where the two theories each contain an alternative new hypotheses, then we should prefer that alternative theory and (and thus) hypothesis which makes for greater content. This is to say that in the comparative evaluation of a pair of new hypotheses, suggested as needed modifications of some pre-existing theory, we should generally prefer that new theory, containing an hypothesis, which together have greater logical comprehension, implying a larger range of testable consequences. But contrast physicist Brian Greene: “rather than trying through one leap, to incorporate all we know about the physical universe in developing a new theory, it is often far more profitable to take many small steps that sequentially include the newest discoveries from the forefront of research.”[8] This claim compares more favorably with Popper’s emphasis on “trial and error” and the “piecemeal approach” in The Poverty of Historicism (1957), and equally with Popper’s emphasis on simplicity in The Open Universe (1982).[9]