| Some Issues on Peirce's Abduction | |
Abstract
Santaella (1992) in the chapter "Harvest Time" presents an excellent summary on the evolution of Peirce's ideas from the three types of arguments or inference to the three types of reasoning finally to the three steps in the scientific investigation, and is it from this work that we took out the main ideas presented in this paper.(1)
In his earlier works, Peirce considered that "all inferences must be reduced in some way to Barbara" (CP2.620), but Peirce's notion of inference evolved turning into the three distinct and irreducible types of arguments or reasoning.(2) At this early stage Peirce included analogy as the fourth type of reasoning but afterwards he recognized that analogy combines the characters of the induction and retroduction. (CP1.65)
Santaella (1993:74) explains the Peircean inference is an essential function of the cognitive mind, and the thought in all its levels presents a similar pattern, that is hypothesis, induction and deduction. So the life of thought in all steps or situations is a question of forming and exercising certain habits of inferences.
For Peirce, the inference is a voluntary act that ends in the "conscious and controlled adoption of a belief as a consequence of other knowledge". It is a casual process that creates or produces beliefs or its acceptance in the reasoner's mind .(CP2.442, 2.44 or5.109) Inferences have three levels: that of the conscious and articulated reasoning, that of the informal everyday inferences without logic control and that of those inferences totally out of our logic control.
In 1866, in "The logic of the Science: or Induction and Hypothesis" Peirce introduces the term hypothesis beside induction and deduction, thus contrary to the current opinion at that time for which there were only two types of arguments: deduction and induction. But in 1867, Peirce is able to show the correlation of the three types of inference with the three figures of syllogism and by denying the Cartesian intuition Peirce is able to solve the problem of the premiss; thus the hypothesis is responsible for the perceptual judgements and for the introduction of the minor premiss in general. The introduction of a new universal affirmation serving as a major premiss can be viewed as the result of the induction and on the other hand the deduction explains the derived conclusions.(3) By that time the inferences were ordered by their certainty level, being its order: deduction, induction and hypothesis.
For Santaella (1993:97), the cognition theory developed by Peirce in 1868-69, and which he completed in the theory of inquiry in 1877-78 brought together his critics to the doctrine of intuition with a new foundation for inquiry, based in a inferential conception of the cognitive mind and also related to the thought-sign theory. But it was only after the discovery of the logic of relatives that Peirce conceives the three types of inferences as distinct and irreducible types of reasoning or arguments.
"Reasoning is of three kinds. The first is necessary, but it only professes to give us information concerning the matter of our own hypotheses (...) The second depends upon probabilities. (...) The third kind of reasoning tries what il lume naturale, (...) can do. It is really an appeal to instinct." (Peirce, CP 1.630)
Between 1890 and 1900, Peirce introduces new modifications and he substitutes hypothesis or hypothetical inference by abduction. From this point on, the threes types of inferences turned into the three steps of scientific investigation, connected as a method and the inference was treated mostly as a methodological process. Peirce's use of abduction was not entirely original, but he was the fist to employ it in the scientific manner. Peirce translated Aristotle's "apagoge" as abduction or the acceptance or creation of a minor premiss as a hypothetical solution to a syllogism whose major premiss we is not known and whose conclusion "we find to be a fact". (CP 7.249)
Anderson(4) emphasises two points related to this question. First, abduction is not a necessary argument but probable (Thirdness) or possible (Firstness). In abduction the acceptance of the minor premiss and the syllogism is provisional and that leads to the second point that is the abduction is outside the purely syllogistic or deductive reasoning. This point is crucial for Peirce's explanation of the abduction as a method and as a logical form because at this point Peirce gets away from the Aristotelian view. For Peirce abduction consists in "examining of a mass of facts and in allowing those facts to suggest a theory". (CP8.209)
In 1902, in a passage (L75:Fv368371,apud Santaella 1992:93) Peirce explains the evolution of his ideas related to the three steps of scientific investigation, saying that due to the excessive weight he laid on formalist considerations he made the mistake of defining hypothesis (which he used as a synonym for abduction) as a model of induction slightly similar to the abduction. Firstly he saw that there had to be three types of arguments strictly relate do the three categories and so he described them in the right way but for Peirce this is the kind of mistake his method of discovery peculiarly tends and even perceiving that a form has a relation with a category, one is unable for a certain time to achieve enough clearness in mind so as to be certain if the relation is the precise required nature.
Although there is some confusion on the differentiation of abduction and induction, we can say that Peirce had never any difficulty in differentiating abduction from deduction because the fist one is ampliative and the other explicative. But he admitted that in almost everything "I printed before the beginning of this century I more or less mixed up Hypothesis and Induction" (CP 8.227). In an other passage Peirce claims that " when after repeated attempts, I finally succeeded in clearing the matter up, the fact shone out that probability proper had nothing to do with the validity of abduction, unless in doubly indirect manner". (CP1.102)
"Nothing has so much contributed to present chaotic or erroneous ideas of the logic of science as failure to distinguish the essentially different characters of different elements of scientific reasoning; and one of the worst of these confusions, as well as one of the commonest, consists in regarding abduction and induction taken together (often mixed also with deduction) as a simple argument". (Peirce, CP 7.218)
Induction does not originate new ideas, only abduction adds something new to thought. Abduction is merely preparatory and it is the first step of the inquiry. But the abduction is the most inefficient " a bolder and more perilous step" than induction (CP2.632) but it is the only responsible for discoveries while the induction is the most efficient being the conclusive step of the scientific reasoning.
"Abduction makes its start from the facts, without, at the outset, having any particular theory in view, though it is motived by the feeling that a theory is needed to explain the surprising facts. Induction makes its start from a hypothesis which seems to recommend itself, without at the outset having any particular facts in view, though it feels the need of facts to support the theory. Abduction seeks a theory. Induction seeks for facts." (Peirce, CP 7.218)
For Peirce, retroduction (abduction) and induction "face opposite ways" The order of the march of suggestion "in retroduction is from experience to hypothesis" .(CP2.755) By induction we conclude "that facts similar to observed facts are true in cases not examined" and by hypothesis we conclude "the existence of a fact quite different from anything observed, from which, according to known laws, something observed would necessary result".
The induction is the reasoning from particular to the general laws and the hypothesis from effect to cause. "Induction classifies, hypothesis explains" (CP2.636) The induction infers the existence of phenomena such as "we have observed in cases which are similar, while hypothesis supposes something of a different kind from what we have directly observed and frequently something which it would be impossible for us to observe directly." (CP2.640) Induction is a "much stronger kind of inference than hypothesis". Hypothesis are sometimes "regarded as provisional resorts" and hypothetical reasoning " infers frequently a fact not capable of direct observation". (CP2.642)
For Peirce " the essence of induction is that it infers from one set of facts another set of similar facts" while hypothesis infers from "facts of one kind to fact of another". So one of the differences between hypothesis and induction is "the impossibility of inductively inferring hypothetical conclusions" (CP 2.642)
There is another distinction between induction and hypothesis, which is associated to an important "psychological or rather physiological" difference in the mode of apprehending a fact. Induction infers a rule, but the belief of a rule is a habit and that habit is a rule active on us. Every belief is of the natures of a habit, therefore, induction "is the logical formula which expresses the physiological process of formation of a habit. The hypothesis "substitutes for a complicated tangle of predicates attached to one subject, a single conception". (CP2.643) There is in this process "an excitation which we could call emotion" so that we could say that hypothesis produces the sensuous element of thought and induction the habitual.
Another merit of the distinction between induction and hypothesis is, that it leads to a very natural classification of sciences: we have the classificatory sciences which are purely inductive such as botany and zoology and then we have sciences of hypothesis-geology and biology. (CP2.643)
For Santaella it is very frequent between Peirce's scholars to confuse the limits of abduction, and they tend to take it for the abductory induction, (CP6.526) which is a kind of vague induction(5) consisting in testing a hypothesis that S is P by observing if S has some characters peculiar to P. The theory of the three types of inference was the way Peirce found to solve the problem of the method of sciences, and in this context the word investigation is nor used only in reference to a mental phenomenon but because some of our activities are guided by sings and symbols that can be submitted to a critic logic.
"... that the rule of induction will hold good in the long run may be deduced from the principle that reality is only the object of the final opinion to which sufficient investigation would lead. " (Peirce CP2.693)
After this brief exposition on the evolution of Peirce's concepts we can focus on abduction. Abduction is the fist step of scientific reasoning (CP7.218) and it is merely preparatory.
Abduction is the process of forming an explanatory hypothesis. It is the only logical operation which introduces any new idea..." (Peirce, CP 5.171)
Abduction is subjected to some conditions: the hypothesis can not be admitted even as hypothesis unless it explains facts or some of the facts. But the stimulus for guessing as derived from experience, the order is from the experience to the hypothesis (CP2.755).
Abduction can be expressed as the following:
"The surprising fact, C, is observed;
But if A were true, C would be a matter of course,
Hence, there is reason to suspect that A is true." (Peirce CP 5.189)
But before we enter the main features of abduction it would be interesting to understand Peirce's view on hypothesis:
"By a hypothesis, I mean, not merely a supposition about an observed object, as when I suppose that a man is a Catholic priest because that would explain his dress, expression of countenance, and bearing, but also any other supposed truth from which would result such facts as have been observed...(...) The first starting of a hypothesis and the entertaining of it, whether as a simple interrogation or with any degree of confidence, is an inferential step which I propose to call abduction. This will include a preference for any one hypothesis over others which would equally explain the facts, so long as this preference is not based upon any previous knowledge bearing upon the truth of the hypotheses, nor on any testing of any of the hypotheses, after having admitted them on probation. I call all such inference by the peculiar name, abduction, because its legitimacy depends upon altogether different principles from those of other kinds of inference." (Peirce, CP 6.526)
In another passage; Peirce explains that Hypothesis may be defined as an argument which proceeds upon the assumption that a character which is known necessarily to involve a certain number of others may be probably predicated of any object which has all the characters which this character is known to involve. (CP5.276)
Abduction studies the facts and projects a theory to explain them. The justification for abduction is that if we are ever to learn anything or to understand phenomena at all, it must be by abduction. For Peirce nobody can be "downright crazy to deny that science has made many true discoveries, but every single item of scientific theory, which stands established today, has been due to abduction. (CP5.172)(6)
Peirce distinguishes two moments in the abductory phase(7) the fist moment is simply the origin of all conjectures that could possibly explain the phenomenon, it is nothing more than guessing.
"...and abduction is, after all, nothing but guessing" (Peirce, CP 7.219).
"The abductive suggestion comes to us like a flash. It is an act of insight, although of extremely fallible insight." (Peirce, CP5.181)
This first moment of abduction is a heuristic moment, in which certain ideas are joined in an out of control way. (CP6.302). This first moment is also characterised by a creative aspect which Peirce considers to be a natural instinctive ability that cannot be reduced to restrictive procedures or formula.
"This Faculty is at the same time of the general nature of Instinct, resembling the instincts of the animals in its so far surpassing the general powers of our reason and for its directing us as if we were in possession of facts that are entirely beyond the reach of our senses. It resembles instinct too in its small liability to error; for though it goes wrong oftener than right, yet the relative frequency with which it is right is on the whole the most wonderful thing in our constitution." (Peirce, CP 5.173) .
In another passage emphasises the genetic affinity between human mind and the laws of nature.
"It is certain that the only hope of retroductive reasoning ever reaching the truth is that there may be some natural tendency toward an agreement between the ideas which suggest themselves to the human mind and those which are concerned in the laws of nature." (CP 1.81)
This instinct which explains why we make right suppositions so frequently is described as a " singular salad (....) whose chief elements are its groundlessness, its ubiquity and its trustworthiness." (MS 692:24)(8)
" Looking out of my window this lovely spring morning I see an azalea in full bloom. No, no! I do not see that, that is the only way I can describe what I see. That is a proposition, a sentence, a fact; but what I perceive is not proposition, sentence, fact, but only an image, which I make intelligible in part by means of a statement of fact. This statement is abstract; but what I see is concrete. I perform an abduction when I so much fabric of our knowledge is one matted felt of pure hypothesis confirmed and refined by induction. Not the smallest advance can be made in knowledge beyond the stage of vacant staring, without making an abduction at every step." (Peirce, MS692)
Thus all knowledge depends on the formulation of a hypothesis, but from a real fact we can only make a may-be inference. Therefore we observe that this inference is frequently positive what turns this phenomenon "the most surprising of all the wonders of the universe." (CP 8.238)
"However man may have acquired his faculty of divining the ways of Nature, it has certainly not been by a self-controlled and critical logic." (Peirce, CP 5.173)
On the other hand, it is not possible to understand the abduction without refering to Peircean cosmology. When Peirce says that the man has a certain instinct for the truth he means that the human mind, as a result of the evolutionary process, has a natural predisposition to make correct guesses about the world. His instinct is a faculty that governs the mind in the direction of the truth even though the presence of chance and error. This connection between abduction, instinct and the evolutionary process is a crucial point in the Peircean theory. For Ibri(9) if we are to enter the merit of the instinct we have to enter the human organism and human own evolution.
" How was it that man was ever led to entertain that true theory? You cannot say that it happened by chance, because the possible theories, if not strictly innumerable, at any rate exceed a trillion -- or the third power of a million; and therefore the chances are too overwhelmingly against the single true theory in the twenty or thirty thousand years during which man has been a thinking animal, ever having come into any man's head. Besides, you cannot seriously think that every little chicken, that is hatched, has to rummage through all possible theories until it lights upon the good idea of picking up something and eating it. On the contrary, you think the chicken has an innate idea of doing this; that is to say, that it can think of this, but has no faculty of thinking anything else. The chicken you say pecks by instinct. But if you are going to think every poor chicken endowed with an innate tendency toward a positive truth, why should you think that to man alone this gift is denied? (Peirce, CP5.591)
Peirce claims that the little chicken ability to find its food is in all aspects similar to the abductory inference, because it chooses while picking up but without reasoning, he does not act deliberately.
"Our faculty of guessing corresponds to a bird's musical and aeronautic powers; that is, it is to us, as those are to them, the loftiest of our merely instinctive powers." (Peirce, CP7.48)
Comparing human abduction with animal instinct, Peirce claims that there is sufficient affinity between the reasoner's mind the nature's to renders guessing not altogether hopeless when they are capable of verification or refutation by comparison to facts. (CP1.121) For Peirce, according to the probability doctrine, it would be impossible to suppose the cause of a phenomenon as pure chance, thus we cannot doubt that there is a great affinity between human mind and nature. In considering the structure of the universe we cannot doubt that human mind has been developed under the influence of nature. (CP5.604 and 7.39) It is one of the human survival factors; the evolutionism is crucial to the logic of Peirce's inquiry. It is the sheet anchor of science. (CP 7.220)
"It is evident that unless man had had some inward light tending to make his guesses on these subjects much more often true than they would be by mere chance, the human race would long ago have been extirpated for its utter incapacity in the struggle for existence..." (Peirce, MS692)
It is true that the elements of the hypothesis are already in our minds even before we come conscious about them, "but it is the idea of putting together what we had never before dreamed of putting together which flashes the new suggestion before our contemplation." (CP 5.181)
"It appears to me that the clearest statement we can make of the logical situation -- the freest from all questionable admixture -- is to say that man has a certain Insight, not strong enough to be oftener right than wrong, but strong enough not to be overwhelmingly more often wrong than right, into the Thirdnesses, the general elements, of Nature. An Insight, I call it, because it is to be referred to the same general class of operations to which Perceptive Judgements belong." (Peirce, CP 5.173)
Peirce describes abduction as an instinctive reason, " spontaneous conjectures of instinctive reason" (CP6.475), emphasising at the same time rational nature and instinctive (the capacity of guessing the right hypothesis). The moment of insight is instantaneous, but the process of constructing and selecting the hypothesis is conscious, controlled, voluntary deliberate subject to criticism and self-criticism. Abduction needs no reason, since it merely offers suggestions, it merely suggests that something may be (CP 5.171) Thus, as man cannot give an exact reason for his best (CP5.173), Peirce qualifies this faculty as "magic" (CP 6.476). In other passages he uses the terms "il lume naturale", natural light, light of nature, instinctive insight. (CP5.604, 6.477, 1.80) For Peirce the processes by which we have intuitions on the world depend on the perceptual judgements because they allow the deduction of universal propositions. " A perceptual judgement is a judgement absolutely forced upon my acceptance, and that by a process which I am utterly unable to control and consequently unable to criticise (CP5.157)
"The third cotary proposition is that abductive inference shades into perceptual judgement without any sharp line of demarcation between them; or, in other words, our first premisses, the perceptual judgements, are to be regarded as an extreme case of abductive inferences, from which they differ in being absolutely beyond criticism." (Peirce, CP 5.181)
For Peirce the perceptual judgements are "the result of a process not sufficiently conscious to be controlled, not controllable and therefore not fully conscious. Both abduction and perceptual judgements are fallible although fallible is indubitable. On the other hand, the perceptual judgement has a component somehow insistent, compulsive that we are obliged to recognise and the abduction appears in lazy free moments and by this reason they have no certainty. There is another difference between perceptual judgements and abduction, which is the lack of critical analysis of the fist ones.
Peirce also call abduction an originary argument, it is originary because it is the only argument that begins with a new idea. Thus is for the abduction that Peirce gives the heuristic originary power. The process of formation of a hypothesis can be confused with the process of formation of judgements but the hypothesis once formed it is the logic verbal expression of a inferential process under control, that is, and a moment of reflection will show that many facts are already presumed when we formulate the logic question, but not the way they were combined.
"When one contemplates a surprising or otherwise perplexing state of things (often so perplexing that he cannot definitely state what the perplexing character is) he may formulate it into a judgement or many apparently connected judgements; he will often finally strike out a hypothesis, or problematical judgement, as a mere possibility, from which he either fully perceives or more or less suspects that the perplexing phenomenon would be a necessary or quite probable consequence." (Peirce, CP 8 229)
It is important to note that Peirce formulates abduction as an inference that has to be ulterior to some state of the mind, but to define it as an inferential formulation is the task of both deduction and induction. We have to observe that "neither deduction nor induction contributes the smallest positive item to the final conclusion of the inquiry, they render the indefinite definite, deduction explicates, induction avaliates. (CP6.475)
There are some Peirce's scholars that suggest that in relating abduction with instinct, abduction would not have a logic form, and being instinct a psychological question, so Peirce would be confusing logic with psychology. For Anderson(10) that deals with this issue, abduction has the same nature as instinct (CP 5.173), it is an insight (CP 5.181) but even though it has a perfectly definite logical form. Anderson continues explaining abduction is paradoxically intuitive, discursive, instinctive and inferential. This instinct is not a mechanism that determines our specific guesses but it is an ability that enables us to guess correctly.(11)
For Santaella (1993:104) in the process of reasoning a proposition is inferred from another according to some mental habit and if instincts are habit they can be interpretant in a process of sign translation, thus instinct theory is compatible with the inferential theory of mental action and contrarily to Descartes' individualism of intuition, the instincts are collective, social, living habits. On the other it is necessary to emphasise Peirce's distinction between abduction and intuition (CP5.213), because abduction takes place in "media res", being influenced by previous thoughts and it needs a certain experience and a problem to be solve before it starts.
Turning now to the second moment of abduction we have to consider the problem of choosing among various hypothesis. How many hypotheses are we able to make on a certain fact? Of course, a lot of, but the main question here is how does operate the process of making hypothesis what kind of interaction is there between human mind and the investigated object so that from all alternative hypothesis only one turns out to be approximately the true one? From all the hypothesis we make we must select one or some of them, but it is interesting to notice that as in the fist step of abduction we need our natural instinct, in the second step this instinct is also required for us to make the correct choice.
"Consider the multitude of theories that might have been suggested. A physicist comes across some new phenomenon in his laboratory. How does he know but the conjunctions of the planets have something to do with it or that it is not perhaps because the dowager empress of China has at that same time a year ago chanced to pronounce some word of mystical power or some invisible jinnee may be present. Think of what trillions of trillions of hypotheses might be made of which one only is true; and yet after two or three or at the very most a dozen guesses, the physicist hits pretty nearly on the correct hypothesis. " (Peirce, CP 5.172)
Selection of hypothesis must follow certain rules. The fist rule says that we should choose first the simplest of all hypothesis (CP6.532) The simplest hypothesis is the easiest and natural, that one to which instinct points to, "that our hypotheses are such as naturally recommend themselves to the mind, and make upon us the impression of simplicity, -- which here means facility of comprehension by the human mind, -- of aptness, of reasonableness, of good sense. For the existence of a natural instinct for truth is, after all, the sheet-anchor of science." (CP7.220) "This rule has another advantage, which is that the simplest hypotheses are those of which the consequences are most readily deduced and compared with observation; so that, if they are wrong, they can be eliminated at less expense than any others. "CP6.532) but the main justification for this criterion is that its emphasis is not placed upon an individual investigator but on the contrary it lays upon a community. The simplicity criterion must be analysed in a bigger context that of the "economy of research", which Peirce presented in an article name " A Note on the Theory of the Economy of Research", 1876 (CP 7.139 -161). By the general designation of "economy of research", Peirce presents some principles that regulate the second moment of abduction, that is economy of money, time, thought and energy (CP 5.600)
By economy Peirce means all human insufficient resources that are used in cognitive works. Form this concept result the following rules:
1. If a hypothesis can be put to the test of experiment" with very little expense of any kind, that should be regarded as a recommendation for giving it precedence in the inductive procedure. For even if it be barely admissible for other reasons, still it may clear the ground to have disposed of it" (CP7.220) The fist thing that economy prescribes is that every guess be broken up into its elements and taken piece-meal.
2. The second rule can be seen as corollary of the first one, we should choose the hypothesis that requires less work to be tested (CP7.93)
3. For when we break the hypothesis into elementary parts, we may, and should, inquire how far the same explanation accounts for the same phenomenon when it appears in other subjects. It accounts for those phenomena, so far as it does account for them, by representing that they are results of chance; or, if you please, of the law of high numbers; for it is remarkable that chance operates in one way and not in the opposite way. Under those circumstances, the economical consideration which we now have in view, would recommend that we at once inquire into non-conservative phenomena, generally, in order to see whether the same sort of explanation is equally admissible in all cases, or whether we are thus led to some broad category of conditions under which non-conservative phenomena appear, or whether there are several distinct ways in which they are brought about. For great economy must result in whichever way this question is answered, provided it can be answered at not too great an expense. (CP7.221)
4. Thus, if we find that there are several explanations of non-conservative phenomena, we have only to trace out their several consequences, and we shall have criteria for distinguishing them; while if we find there is but one cause, we at once reach a wide generalisation which will save repetitious work. It is, therefore, good economy, other things being equal, to make our hypotheses as broad as possible. But, of course, one consideration has to be balanced against another. There still remains one more economic consideration in reference: if it does not suit the facts, still the comparison with the facts may be instructive with reference to the next hypothesis. (CP7.221)
All these rules assembled together will allow the inquirer to make a cost benefit analysis considering that resources are scare, considering that the possible number of explanations can be very high as well as the verifying process cost, so that " economy would override every other consideration even if there were any other serious considerations. In fact there are no others. For abduction commits us to nothing. It merely causes a hypothesis to be set down upon our docket of cases to be tried". (CP 5.602)
There are various types of explanatory hypothesis:
The Peircean criteria for choosing hypotheses are constructed under socio-historic terms so that one hypothesis should be preferred not only because its intrinsic merits and truth but because of the role it can represent on the long term process of investigation and also from researchers community point of view. Additionally we should take into account that the hypothesis must be capable of being subjected to experimental testing. In the second place, the hypothesis must be such that it will explain the surprising facts we have before us which it is the whole motive of our inquiry to rationalise and in the third place, quite as necessary a consideration as either of those I have mentioned, in view of the fact that the true hypothesis is only one out of innumerable possible false ones, in view, too, of the enormous expensiveness of experimentation in money, time, energy, and thought, is the consideration of economy. (CP7.220)" It is to be remarked that the theory of economy rests on the supposition that the object of the investigation is the ascertainement of truth. (CP7.157)
But in order that the process of formulating a hypothesis comes to a result it is required the following instructions:
Thus abduction should be understood in an efficiency context as a model for hypothesis explanation choice in a way to minimise time. Abduction is the necessary condition for start of the investigation(13)
"An Abduction is a method of forming a general prediction without any positive assurance that it will succeed either in the special case or usually, its justification being that it is the only possible hope of regulating our future conduct rationally." (Peirce, CP 2.270).
The meaning of a hypothesis is the sum of all its experiential consequences, i.e., what it can imply for induction. Therefore, the pragmatism concerns the logic rules that govern the admissibility of hypothesis as hypothesis.(14) For Peirce the pragmatism is the logic of abduction. Peirce asks: What is good abduction? What should an explanatory hypothesis be to be worthy to rank as a hypothesis? But what are the conditions a good hypothesis ought to fulfill to be good? What, then, is the end of an explanatory hypothesis?
"Of course, it must explain the facts. But what other conditions ought it to fulfill to be good? The question of the goodness of anything is whether that thing fulfills its end. What, then, is the end of an explanatory hypothesis? Its end is, through subjection to the test of experiment, to lead to the avoidance of all surprise and to the establishment of a habit of positive expectation that shall not be disappointed. Any hypothesis, therefore, may be admissible, in the absence of any special reasons to the contrary, provided it be capable of experimental verification, and only insofar as it is capable of such verification. This is approximately the doctrine of pragmatism." (Peirce, CP 5.197)
On the other hand the main function of a hypothesis is to explain facts so the pragmatism will act as a choice and decision factor among alternative or competitive hypothesis so that afterwards by an inductive process it will turn the merely hypothetical into merely possible, or in other words, from the hypothesis to the belief there is the necessary passage from the possible to the probable. But form the point of view of pragmatism the main issue is the consequences of a hypothesis, i.e., for a hypothesis to be meaningful it needs to produce some effects. No true hypothesis can be attacked by doubt nor will be taken aback by conflicting experiences.
Sometime Peirce uses the term retroduction as a synonym for abduction, the term "apagoge" in Aristotle was misunderstood because of corrupt text and as misunderstood usually translated abduction (CP1.65)
Retroduction can be defined as:
"Retroduction is the provisional adoption of a hypothesis, because every possible consequence of it is capable of experimental verification, so that the persevering application of the same method may be expected to reveal its disagreement with facts, if it does so disagree." (Peirce, CP1.68)
Or this other definition:
"The function of retroduction is not unlike those fortuitous variations in reproduction which played so important a role in Darwin's original theory. In point of fact, according to him every step in the long history of the development of the moner into the man was first taken in that arbitrary and lawless mode. Whatever truth or error there may be in that, it is quite indubitable, as it appears to me, that every step in the development of primitive notions into modern science was in the first instance mere guess-work, or at least mere conjecture. But the stimulus to guessing, the hint of the conjecture, was derived from experience. The order of the march of suggestion in retroduction is from experience to hypothesis". (Peirce, CP 2.755)
Rescher(15) divides the hypothetico-inductive inquiry labour in science can be divide into tow distinct processes or procedures:
In being a "quasi-reasoning", the abduction has a power for discoveries, but at the same time it is uncertain and limited because it has no probative force (CP 8.210) and the conclusion of a hypothesis is problematic or conjectural. (CP.5.192) Peirce either emphasises this characteristic of abduction in employing terms such as fair guess, extremely fallible insight, not strong enough to be oftener right than wrong, but strong enough not to be overwhelmingly more often wrong than right (CP2.623, 5.181, 5,173) or he claims categorically that there is no security in respect to abduction/retroduction:
"Retroduction does not afford security. The hypothesis must be tested. This testing, to be logically valid, must honestly start, not as Retroduction starts, with scrutiny of the phenomena, but with examination of the hypothesis, and a muster of all sorts of conditional experiential consequences which would follow from its truth" (Peirce, CP 6.470)
For Santaella (1993:95), the abduction even being the weakest type of logic argument it is ideal to the art necessities, because the art has no compromise with truth of the science, so related to the invention of a explicative hypothesis it is the only reasoning through out creativity can be expressed in art or in science, it can be the meeting point for the two.
Anderson, in "Scientific Creativity", analyses abduction form the creativity point of view and he claims for it different levels of creativity in abduction.(16) Although Peirce was interested in the entire range of abductions, he "was most interested in those abductions which allowed science to grow, the only kind of reasoning which supplies new ideas" i.e., we want to know generally what is that persons such as Copernicus, Kepler, Newton, and Einstein do when they are scientifically creative. These are examples of the more creative abduction; each of these essentially twists the standard view of reality in a radical way. But it is possible to admit that there are abductions, which are not original. There are repetitive abductions, which take place in similar circumstances in the story of science. Peirce also admits this point by acknowledging the originality of an abduction when two or more persons arrive at it at the same time. (CP2.714, 4.431) There is a form of abduction that Peirce calls induction of characters, it is creative in the sense that it is both synthetic and clever, but it does not create a new idea. (CP2.626, 2.629)
"Hypothesis has been called an induction of characters. A number of characters belonging to a certain class are found in a certain object; whence it is inferred that all the characters of that class belong to the object in question" (Peirce, CP 2.632)
Peirce claims that abduction is the most important type of reasoning (NEM 3.206) We can say that the importance of abduction cannot be restricted to the elaboration of hypothesis but it has influence on the perception theory (CP5.181), it has an essential role in memory (CP2.265), is essential for History (CP6.606 and 2.714) besides being the essence of pragmatism, as the logic of abduction (CP5.195-205)
NOTES
(1) L.SANTAELLA (1992) "Tempo de Colheita" em A Assinatura das Coisas, Rio de Janeiro:Imago.
L. Santaella (1993) Metodologia Semiótica:Fundamentos, tese de livre docência inédita, São Paulo ECA/ USP p.113. D Anderson, (1987) "Scientific Creativity" em Creativity and The Philosophy of C.S.Peirce, pp.12/53.
(2) B. Serson, (1992) La théorie sémiotique de la cognition chez C.S.Peirce, tese de doutoramento, pp. 64-91.
(3) L. Santaella (1992) op.cit. p. 87.
(4) D. Anderson (1987) ,op.cit, p.15
(5) L.Santaella (1992) op.cit. pp.93-97
(6) C. Eisele (1985) Historical Perspectives on Peirce's Logic of Science. Berlin/ New York/ Amsterdam: Mouton, 2 vols. p. 899.
(7) C. F. Delaney, (1993). Science, Knowledge and Mind - A Study in the Philosophy of C. S. Peirce. Notre Dame/London:University of Notre Dame Press. p. 15.
(8) C. Eisele (1985) Historical Perspectives on Peirce's Logic of Science. Berlin/ New York/ Amsterdam: Mouton, 2 vols. p. 899.
(9) I. Ibri, (1996) "A abdução e o evolucionismo", palestra ministrada na Puc.
(10) D. Anderson, (1986) "The Evolution of Peirce's Concept of Abduction", Transactions of the Charles S.Peirce Society, vol XXII,n.2 p.145-64 e R. Roth, (1988) "Anderson on Peirce's Concept of Abduction: Further Reflections", Transactions of the Charles S.Peirce Society, vol. XXIV, n.1 p.131/139, P. Forster, (1989) "Peirce on the Progress and Autorithy of Science", Transactions of the Charles S.Peirce Society, vol. XXV, n.4, pp.421-452.
(11) CP 7.220, 6.530, 5.591, 5.604 AND 6.476
(12) CP 6.488,5.547,6.259
(13) N. Rescher, (1978) Peirce's Philosophy of Science-Critical Studies in His Theory or Induction and Scientific Method, p. 48.
(14) B. Serson, (1992) La théorie sémiotique de la cognition chez C.S.Peirce, tese de doutoramento, pp. 64-91.
(15) N. Rescher, (1978) op.cit.,p.8.and 41
(16) D. Anderson (1987), op. cit. p. 12-53.