People reason in one of three general ways: deductively, inductively, or abductively. Assuming that one’s argument is valid in form and each individual premise is true, the conclusions of deduction are logically certain. Induction and abduction yield no such logical certainty. Induction is based upon observation of repeated experience, and thus leads one to a probable conclusion. Abductive reasoning offers one neither a certain nor probable conclusion. It does, however, attempt to offer an explanation of the facts, why things are the way they are. In other words abduction seeks to determine the most plausible solution to a problem.
Abduction is a type of pragmatic reasoning, given its formal name by the American philosopher Charles Sanders Peirce (1839-1914).1 Peirce did not invent abduction; human beings have always practiced it. He did, however, give formal expression to something that people have always done, thus allowing future reasoning of this sort to be done in a more critically aware and consistent manner. Abduction is a hybrid form of reasoning, sharing certain characteristics with both induction and deduction, while remaining neither. Like induction abduction makes us of a posteriori observation to reach its conclusion, a conclusion not guaranteed to be true. Unlike induction it is not simply about the probability of such and such being the case based upon repeated or prior observation. Like deduction abduction begins with an a priori hypothesis (rule) and reasons to an application of that rule in particular. Despite the fact that neither induction nor abduction renders a conclusion certain,2 both are nevertheless important forms of reasoning.
The logical order differs in the three different types of reasoning. Deduction works from rule to case to result; induction, from case to result to rule; and abduction, from rule to result to case. The differences in logical order are illustrated below:
Rule All A are B
Rule All the beans from this bag are white
Case C is A
Case These beans are from this bag
Result Therefore C is B
Result Therefore these beans are white
Case C is A
Case These beans are from this bag
Result C is B
Result These beans are white
Rule Therefore all A are B
Rule All the beans from this bag are white
Rule All A are B
Rule All the beans from this bag are white
Result C is B
Result These beans are white
Case Therefore C is A
Case Therefore these beans are from this bag
But perhaps an example from Sir Arthur Conan Doyle would be more helpful (and enjoyable).
The portly client puffed out his chest with an appearance of some little pride and pulled a dirty and wrinkled newspaper from the inside pocket of his greatcoat. As he glanced down the advertisement column with his head thrust forward and the paper flattened out upon his knee, I took a good look at the man and endeavored, after the fashion of my companion, to read the indications which might be presented by his dress or appearance.
I did not gain very much, however, by my inspection. Our visitor bore every mark of being an average commonplace British tradesman, obese, pompous, and slow. He wore rather baggy gray shepherd’s check trousers, a not over-clean black frock-coat, unbuttoned in the front, and a drab waistcoat with a heavy brassy Albert chain, and a square pierced bit of metal dangling down as an ornament. A frayed top-hat and a faded brown overcoat with a wrinkled velvet collar lay upon a chair beside him. Altogether, took as I-would, there was nothing remarkable about the man save his blazing red head and the expression of extreme chagrin and discontent upon his features.
Sherlock Holmes’s quick eye took in my occupation, and he shook his head with a smile as he noticed my questioning glances. “Beyond the obvious facts that he has at some time done manual labor, that he takes snuff, that he is a Freemason, that he has been in China, and that he has done a considerable amount of writing lately, I can deduce nothing else.” Mr. Jabez Wilson started up in his chair, with his forefinger upon the paper, but his eyes upon my companion. “How, in the name of good-fortune did you know all that, Mr. Holmes?” he asked. “How did you know, for example, that I did manual labor? It’s as true as gospel, for I began as a ship’s carpenter.”
“Your hands, my dear sir. Your right hand is quite a size larger than your left. You have worked with it, and the muscles are more developed.”
“Well, the snuff, then, and the Freemasonry?”
“I won’t insult your intelligence by telling you how I read that, especially as, rather against the strict rules of your order, you use an arc-and-compass breastpin.”
“Ah, of course, I forgot that. But the writing?”
“What else can be indicated by that right cuff so very shiny for five inches, and the left one with the smooth patch near the elbow where you rest it upon the desk?”
“Well, but China?”
“The fish which you have tattooed immediately above your right wrist could only have been done in China. I have made a small study of tattoo marks and have even contributed to the literature of the subject. That trick of staining the fishes’ scales of a delicate pink is quite peculiar to China. When, in addition, I see a Chinese coin hanging from your watchchain, the matter becomes even more simple.”
Mr. Jabez Wilson laughed heavily. “Well, I never!” said he. “I thought at first that you had done something clever, but I see that there was nothing in it, after all.”3
Commenting on this story, Louis Pojman notes that Holmes’s description of what he does is inaccurate. Holmes claims to be deducing his conclusions about Mr. Wilson on the basis of observing various telltale signs, but is in fact doing no such thing. “In deductive reasoning, if the form is correct and the premises are true, one cannot help but obtain a true conclusion, but such is not the case with Holmes’s reasoning.”4 Pojman asks us to consider Wilson’s arc-and-compass breastpin, which leads Holmes to conclude that Wilson is a Freemason. If Holmes’s reasoning were deductive, the argument would run something like this:
If one wears an arc-and-compass breastpin, then he is a Freemason.
Mr. Wilson is wearing an arc-and-compass breastpin.
Therefore Mr. Wilson is a Freemason.5
Is this argument sound? No, not at all. As a deductive argument it is a valid form of a hypothetical syllogism (modus ponens-way of affirmation). But unfortunately for Holmes the consequent is not entailed in the antecedent.6 There are many other reasons that someone might wear an arc-and-compass breastpin. Pojman asks us to consider the possibility that Mr. Wilson, who is not a Freemason, bought a similar arc-and-compass breastpin at a pawn shop and wore it, thinking it was a beautiful bit of Moslem design.7 In that case, premise 1 would be false-one can wear an arc-and-compass breastpin without being a Freemason. Because it is sensible that non-Freemasons wear that pin, the above deductive argument is not sound. Nevertheless the single most plausible explanation for Mr. Wilson wearing the arc-and-compass breastpin is that he indeed belongs to the Freemasons. What Holmes has really done is reason abductively, i.e., reason to the best explanation of the facts.
Of the three types of reasoning, it is abduction that offers one the most extensive range of reference. Deduction is entirely analogical, or self-referential. It imparts no new information and refers only to what is found within the proposition under consideration. Induction, on the other hand is synthetic in nature, it does refer to objects that exist outside the proposition considered. Nevertheless, it is limited to conclusions that can be reached through repeated or prior experience. Abduction, on the other hand, is able to introduce new ideas, to solve problems, and to lead one to new explanations of life and reality. It is, as Peirce notes, “the only logical operation which introduces any new idea.”8 Furthermore, it is not dependent upon prior experience as is induction. Judged in terms of reference, abduction is clearly the most significant type of reasoning.
We must be aware that what abduction gains in terms of reference, it sacrifices in certainty. While abduction is the only type of reasoning that refers one to new information, it is also the least certain. Deduction applied properly yields a necessary conclusion-one that cannot not be true. Induction applied properly yields a probable conclusion-one that is to be preferred over all other possible answers taken together, not simply over any other single option, as is the case with abduction. Abduction, on the other hand, applied properly, yields only the most plausible conclusion. This means that the best available abductive solution might nevertheless be quite improbable-and thus likely to be mistaken. This is not to say that abduction is less important than deduction or induction. It is to say that our listeners need not only a creative word, but also a certain word. After all, biblical prophets declared, “Thus saith the Lord,” not “Divine judgment is the likeliest explanation for our present distress.” We must therefore maintain balance in our reasoning. All three types of reasoning have their strengths and weaknesses, and they all have their place in our preaching.9
What most seems to attract Sweet to abduction is Peirce’s insistence that we formulate abductive hypotheses quite apart from conscious reflection, in an instinctual, non-linear fashion, so to speak.10 He insisted that there was something immediate and intuitive in the “guessing” of abduction.11 Accordingly, those preaching to postmoderns would do well to preach in such a way that their listeners are stimulated to consider new (abductive) solutions to the problems of life. To this end he insists that we make use of surprising stories and symbols that awaken the imagination to the possibility of the Christian worldview and a personal relationship with Christ through faith.
I am certain that abductive reasoning, used properly, has much to offer the preacher. One reason this is so is its usefulness in communicating a worldview.
The Christian preacher’s task is not only to explicate a text, but also to present the Christian worldview clearly. Worldviews are communicated through four primary media: story, symbol, ultimate questions, and praxis.12 There can be no doubt that Sweet is urging us to preach in terms of both story and symbol. We dare not forget that Jesus told stories (parables) that demanded abductive interpretation. Our pluralistic society, replete with competing stories (metanarratives) of how life and the world should be understood, is very much like the one in which Jesus and his apostles lived. There is tremendous pressure upon believers to compromise and present the biblical story as just one local story among many other local stories, each of which is equally valid-but to do so would be not only illogical (because contradictory positions cannot both be true) but also untrue to Jesus’ story, since he clearly intended for his hearers to understand that his story was singularly true. Jesus made use of stories (parables), visual symbols (baptism, Lord’s Supper), and verbal symbols (metaphors, aphorisms). Therefore we must re-tell the same story that Jesus told in his preaching and his actions. Abduction can be very helpful in this regard.
Additionally, abduction offers us some criteria for evaluating the competing stories being told in today’s society. While there are no universally recognized criteria for determining the likeliest case, certain criteria routinely come up. Louis Pojman mentions four: (1) Coherence – Is the theory consistent with everything or nearly everything else that we hold true in a given field? Also, is it internally consistent? (2) Simplicity – Is the theory simpler than its rivals, does it demand fewer ad hoc, or auxiliary, hypotheses? Simpler theories are less likely to fail because they have fewer opportunities to do so. (3) Predictability – Does the theory help us predict future events? (4) Fruitfulness – Does the theory lead to new insight and discoveries?13 To Pojman’s four criteria I would like to add two more: (5) Comprehensiveness – Does the theory account for all the available data? Coherence and simplicity are much more easily attained if one disregards problematic data, but the conclusion is likely to be flawed; and (6) Consistency – Does the conclusion have the ring of authenticity? Which does it more nearly resemble: real-life explanation or conspiracy theory? Would something highly out of the ordinary have to happen for which there is no explanation for the theory to work? Abductive reasoning gives one the logical means to prefer one worldview over against all others according to criteria other than what one has always been taught or believed.14 By integrating these criteria into our preaching, we can preach both apologetically and evangelistically. In other words, we can demonstrate the insufficiency of non-Christian worldviews and false gospels while emphasizing the truthfulness of the Christian worldview. In this way, we can faithfully proclaim Jesus as the only Savior of the world.
Sweet rightfully trumpets the value of the unexpected. Good stories have plot twists, which draw readers (or listener or viewer) in and make them think. Most, if not all, of Jesus’ parables were far more than simple morality tales-they were actually subversive narratives. Simply put, Jesus shocked his hearers not only with what he said, but also with how he said what he said. In other words, in this way Jesus used abduction. So if we want to be like Jesus, perhaps our preaching should be shocking, too!
But I must add another word of caution. We must not forget that what is gained by an abductive moment of insight may be lost in terms of clarity. What our hearers “get” might be something other than the Gospel. In other words, they may form explanatory hypotheses that are not actually explanations at all (and certainly not the Gospel of Jesus).15
On the other hand, those of us who have preached to real-life congregations for any significant period of time know that whatever model of preaching we adopt we will be misunderstood by some. After all how many of us have never had the experience of being congratulated for preaching a message that we not only are certain we never delivered-no matter how often we tongeled our tangues-we also are positive we could not even have conceived? Does this mean that we should control the reaction of our hearers? Not necessarily. We are all aware of the impossibility of doing that, anyway. Who among us has not preached what we thought was a gem of a sermon only to observe absolutely no obvious reaction to it? Similarly, haven’t we all had the experience of preaching what we thought was a below average sermon only to observe numerous decisions for Christ in response. This just goes to show that the Holy Spirit is not under our control. But this does not mean that we should not do all we can to ensure that our listeners hear what we are actually saying. In other words we must do all we can to make certain that our listeners are shocked by God’s message, not ours. To this end, we must hear his voice before stepping into the pulpit. Such is, of course, the case whatever method of reasoning we adopt when preaching. But given its unpredictable nature, abduction is not something to be handled lightly or hurriedly.
No doubt there is much more that could (and probably will) be said concerning Sweet’s proposal, but time and space do not permit me to do so. I hope that this article has helped some to understand abduction better and to consider critically whether or not it is boon or bane for preaching.
Robert B. Stewart is Assistant Professor of Philosophy and Theology at New Orleans Baptist Theological Seminary.
1 Peirce also calls abduction “retroduction” or “hypothesis.” See C. S. Peirce, Philosophical Writings of Peirce, ed. Justus Buchler (New York: Dover, 1955), esp. 150-56; 190-217; idem, Collected Papers of Charles Sanders Peirce, ed. Charles Hartshorne, Paul Weiss, and Arthur Banks (Cambridge, MA: Harvard University Press, 1935-1966), esp. 5:157-206; idem, Chance, Love, and Logic (New York: Harcourt Brace, 1923). For useful secondary studies on Peirce’s abductive method, see A. J. Ayer, The Origins of Pragmatism: Studies in the Philosophy of Charles Sanders Peirce and William James (San Francisco: Freeman, Cooper, and Company, 1968); and K. T. Fann, Peirce’s Theory of Abduction (The Hague: Martinus Nijhoff, 1970). Citations of Peirce’s Collected Papers refer to sections, not page numbers.
2 One must bear in mind the difference between logical certainty and psychological certainty. Induction does render many things psychologically certain-so much so that we are functionally unable to doubt much of what we have learned through induction, which amounts to practical certainty.
3 Arthur Conan Doyle, “The Red-Headed League,” The Complete Sherlock Holmes (New York: Barnes and Noble, 1992), 177. Examples from Conan Doyle’s fictional detective are fairly standard in the study of abductive reasoning. E.g., see Umberto Eco and Thomas A. Sebeok, The Sign of Three: Dupin, Holmes, Peirce (Bloomington and Indianapolis: Indiana University Press, 1988).
4 Louis Pojman, Philosophy: The Quest for Truth, 4th ed. (Belmont, CA: Wadsworth, 1999), 29.
5 I have chosen to illustrate this point through the above hypothetical syllogism. Pojman uses a categorical syllogism:
1. Everyone wearing an arc-and-compass breastpin is a Freemason.
2. Mr. Wilson is wearing an arc-and-compass breastpin.
Therefore, Mr. Wilson is a Freemason.
The difference is merely formal. The point is the same.
6 The antecedent is the first portion of the first premise, the “If” section. The consequent is the following portion of the first premise, the “then” section.
7 Pojman, 29.
8 Peirce, Collected Papers, 5:171.
9 I take the following statement from page 2 of Sweet’s paper as an indication that he understands this point: “There are multiple modes of cognition, some more imaginative, others more rational. The mind moves from one to another all the time. They are in fact interdependent.” I stress it only because of its importance.
10 It appears that Sweet is appealing to what Umberto Eco calls Creative Abduction. Eco helpfully identifies four types of abduction for us: (1) Overcoded Abduction-When the interpretive law (or hypothesis or framework) is supplied automatically/immediately. An example of this sort of subconscious reasoning, in which one makes a choice somewhat automatically, without giving conscious consideration to one’s choice concerning the meaning of a sign, would be assuming that when one hears the sound “man” in a cosmopolitan setting that one is hearing the English word for a male rather than some other word that sounds the same in another language; (2) Undercoded Abduction-When the interpretive law (or hypothesis or framework) is selected from multiple options that are equally probable; (3) Creative Abduction-When no interpretive law (or hypothesis or framework) via which one interprets data exists and therefore a new law must be created by the investigator. An example of this sort of abductive reasoning is the sort of “paradigm construction” that Thomas Kuhn writes about in his book, The Structure of Scientific Revolutions (Chicago: The University of Chicago Press, 1962); (4) Meta-Abduction-This sort of abduction relates only to creative abduction, not to over- or undercoded abduction because their models and conclusions are drawn from the existing, prior world of human experience. The paradigm proposed by creative abduction does not. Therefore meta-abduction tests the proposed paradigm as to its verifiability (Umberto Eco, “Horns, Hooves, and Insteps: Some Hypotheses on Three Types of Abduction,” in Thomas A. Sebeok, The Sign of Three: Dupin, Holmes, Peirce [Bloomington: Indiana University Press, 1983], 206-7). In my response at EHS I suggested that Sweet was primarily thinking of overcoded abduction. Upon further reflection, I have decided that it is creative abduction that he has in mind.
11 Peirce, Collected Papers, 7:219.
12 N. T. Wright, The New Testament and the People of God, vol. 1, Christian Origins and the Question of God (Minneapolis: Fortress Press, 1992), 122-26. Some teach that worldviews are best analyzed via philosophical categories such as ontology, epistemology, cosmology, ethics, etc. Such an approach is not wrong, and quite useful as a second level of analysis in fact, but immediately leads to worldviews that are so broad and general (theism, pantheism, panentheism) that they are somewhat misleading. After all both Islam and Christianity fall under the “worldview” of theism (or even monotheism). But clearly the Christian worldview is not the same as the Islamic worldview, nor is the Buddhist worldview the same as the Hindu worldview, even though both Buddhism and Hinduism are at least somewhat pantheistic in nature. (One could, of course, argue that Buddhism is actually atheistic in nature, and be correct, but Buddhism and Secular Humanism are nevertheless quite different.)
13 Louis Pojman, Philosophy: The Quest for Truth, 4th ed (Belmont, CA: Wadsworth, 1999), 30.
14 This means that we must preach apologetically not merely evangelistically.
15 The task of preaching is not to deliver a new word but to present God’s word in the appropriate way. Often the very best thing one can do is to preach a deductive message that presents the truth of Scripture in a clear and elementary fashion.