4 Two Unreceived Views about Reasoning and Argument

My interest in these topics continues to this day, and I have written and commented further on both of them. I remain grateful to John Wisdom for permitting me to read his lectures on explanation and proof, popularly known as the Virginia Lectures, and to Roger Shiner for loaning me his copy of that fascinating material. The doctoral work of Jerome Bickenbach and the summary provided by Renford Bambrough were also helpful and should remain of interest to scholars. The topic of analogical arguments has been of interest to others, notably Marcello Guarini and Lilian Bermejo-Luque and their students.

The question of whether a priori analogies should be considered as distinct from deductive arguments also remains of interest; I sense some consensus in favour of an affirmative answer to that question. In any analogy the target case (topic in question) and the analogue are both similar and different. Assessment of an argument based on analogy presupposes awareness of those similarities and differences, and hinges mainly on the issue of their significance (in support, or in objection) to the conclusion claim. Reconstructing those arguments with a universal claim regarded as a missing premise remains a temptation for analysts and theorists. It is a temptation I would still resist, for reasons given here. Of course reconstructing by adding a universal missing premise is not the only way of rendering a priori analogies deductively valid; one can take a modus ponens approach using the associated conditional.

Clearly, if one thinks that a priori analogies are not deductive arguments, one presumes a distinction between the a priori and the deductive. One might say that a question is a priori if it is to be resolved by considerations of concepts, criteria, meaning, and significance; accordingly a style of argument would be a priori if these features characterize it. When we ask whether a priori analogies are deductive arguments, we need to ask what sort of argument counts as deductive. The matter is problematic. One might say that an argument is deductive if the truth of its premises render the falsity of its conclusion impossible or if the arguer intends that to be the case. On such a definition, it is clear that the a priori and the deductive may be distinguished. (Of course Kant thought so long ago, for different reasons.) Given these conceptions of the a priori on the one hand and the deductive on the other, I continue to maintain that a priori analogies are not deductive.

John Wisdom argued that due to its role in settling questions about the application of words, case-by-case reasoning was more fundamental for human thought than either deduction or induction. So far as I am aware, that challenging hypothesis has not been seriously studied.

Carl Wellman’s ideas about conductive argument received little attention for many years, but have recently been subject to sustained discussion and criticism. My own developments of Wellman’s ideas have been part of that picture. A key volume, resulting from a Windsor conference is Conductive Arguments: An Overlooked Type of Defeasible Reasoning, edited by Ralph Johnson and J. Anthony Blair. Topics considered in recent discussions include the convergent/linked distinction, ways of diagramming the structure of conductive argument, the role of counter-considerations in argument, the distinction between counter-considerations and objections, and the appropriacy of such language as ‘weighing’ and ‘balancing’ in considering the significance of cumulating factors. In his work The Concept of Argument, Harald Wohlrapp argues that the pros and cons of conductive argument can better be understood as stages in an ongoing discussion, so that in a process (as distinct from product) model of argument, the category ‘conductive’ will disappear.

It is quite possible that a priori analogies and conductive arguments are not the only types of arguments ignored because of the misleading and spurious exhaustiveness of the inductive/deductive distinction. If ‘inductive’ is so broadly defined that every non-deductive argument counts as inductive, the inductive category will include a large variety of argument types. For example, it is common to think of abductive arguments as inductive. Abductive arguments have not been ignored by theorists, a fact that may be due to their importance in scientific reasoning. A close study of a variety of works inside and outside philosophy might well reveal other candidates that are neither deductive nor empirically inductive in nature. I suspect it would. Perelman and Olbrechts-Tyteca’s The New Rhetoric could serve as an excellent starting point in the quest for examples.

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The prevailing theories of argument among philosophers seem to be deductivism and positivism. Of course there have been dissenters from these views. Some dissenters, such as Wittgenstein, Toulmin, and Perelman, were people of considerable professional prominence. Despite this, their views on argument have not greatly influenced thinking about logic and argument.

Among dissenting views on reasoning and argument, two are of particular interest. The first is that of John Wisdom, elaborated most completely in the unpublished lectures ‘Explanation and Proof’, presented at the University of Virginia in 1957, and commonly known as the Virginia Lectures. In these lectures, Wisdom described what he called ‘case-by-case reasoning’ or ‘reasoning by parallels’.¹ He argued that it was a nondeductive, noninductive, type of reasoning which was, in fact, more basic than either deduction or induction. The second neglected, but interesting, view is that of Carl Wellman, articulated in 1971 in Challenge and Response: Justification in Ethics.² Like Wisdom, Weldon challenged the prevailing belief that arguments are either inductive or deductive. He defined a third category which he called ‘conductive’, in which distinct, separately relevant factors are cited to support a conclusion. Wellman was concerned to show the relevance of conductive arguments to issues about the justification of moral beliefs; however his account has broader application as well as this single important one.

Although case-by-case reasoning and conductive reasoning are not the same, they fit into a similar gap in the theory of argument and may have been widely ignored by philosophers for similar reasons. Both fail to supply deductive support to conclusions and yet are frequently used in a priori contexts to resolve issues that are conceptual, philosophical, normative, or in some other sense nonempirical. In addition, both seem recalcitrant to treatment by general rules. Case-by-case reasoning depends on specific similarities and differences between individual cases. These cases have to be compared and ‘seen’ as such, rather than handled by covering generalizations. Conductive reasoning depends fundamentally on judgments of positive and negative relevance and on how these separately relevant pro and con factors are significant when considered in the balance.

1. Wisdom’s Virginia Lectures

John Wisdom’s Virginia Lectures offer a sustained elaboration and defence of a view which he applied and formulated more briefly in some of his published work. The lectures are conveniently and accurately summarized in a paper by D. Yalden-Thomas, available in a collection of essays on Wisdom’s philosophy. They were the subject of several doctoral dissertations in the late nineteen fifties and of a thorough analysis in a 1977 doctoral dissertation by Jerome Bickenbach. To some extent, Wisdom’s views have been promulgated by his former students and colleagues: several works on meta-philosophy and meta-ethics, including Renford Bambrough’s Moral Scepticism and Moral Knowledge. Stephen Barker’s Elements of Logic shows Wisdom’s influence, particularly in footnotes and cautionary comments in the third edition. Barker was in the audience in Virginia, and some of his questions and comments appear in the typescript of the lectures.³ On the whole, however, Wisdom’s views have had little influence on those who reflect on the nature and types of argument.⁴ Even a recent paper concerned to defend analogy as a distinct form of inference and referring to a wide variety of sources neglects Wisdom’s view.

According to Wisdom, the most basic, primary, kind of reasoning is case-by-case reasoning. This reasoning is used, either explicitly or implicitly, in order to show that a word is properly applied to a particular case. Since both deduction and induction presume the proper application of words to particular instances, any kind of reasoning which is a prerequisite of doing this can lay claim to ‘most basic’ status. Examples of instances where issues of correct application of a term arise are whether a pattern of behavior amounts to negligence; whether the Jews constitute a nation; and whether a trailer that has been fixed in one position is still a mobile home. There may be important disputes in such cases and there is a rational way to resolve them. We find an instance which is clearly a case of negligence, nationhood, being a mobile home, or whatever, and we closely compare and contrast that instance with the unresolved one. The only way to show that terms have been correctly applied is to reason from agreed instances of their correct application. In this way, we can argue for a conclusion on the point. Case-by-case reasoning is a species of argument from analogy.

Wisdom considered four sorts of contexts in which case-by-case reasoning is necessary: where we need to resort to comparison with a paradigm; where we are evaluating ‘paradoxical’ statements such as those commonly made in metaphysics; where we are trying to resolve borderline cases; and where criteria are not sufficiently explicit to bring out correct standards of applicability in a process of deduction. The second context here is tied to metaphilosophical disputes in the forties and fifties, and merits some explanatory comment. Wisdom had in mind such claims as ‘nothing is really solid’. His concern was to show that reasons could be offered for and against such metaphysical statements, and that they were not meaningless as positivists had maintained but were, rather, significant statements — though not about either matters of fact or matters of verbal usage.

Questions about the correct application of such terms as ‘solid’, ‘negligence’, ‘nation’, ‘race’, ‘solvent’, and many others are not purely verbal: they may have profound legal, political, moral, or psychological significance. Wisdom had an ingenious way of contrasting purely verbal disputes with significant conceptual ones. He claimed that if two people have a purely verbal dispute, their disagreement could be explained by the way in which they have used words in the past. Their past usage would be divergent. However, in a case where two people are disagreeing on a significant conceptual issue, such as whether anything is really solid, in the light of particle physics, this disagreement is not necessarily reflected in differences as to how they have previously applied the term. Rather, it is a difference as to the correct decision about how the term should be used in the future, in the light of significant new data. Nor is the difference between them a factual one, for it will not be resolved by future observations. In an inductive argument, we reason to a conclusion that can, in principle, be determined in some other context to be true or false on the basis of empirical observation. But here, the issue is one that requires decision as distinct from prediction.

Where some authors have contrasted a priori and inductive analogy, Wisdom tends to use ‘analogy’ to refer to inductive analogy and to call what others term ‘a priori analogy’ case-by-case reasoning. The difference as he understands it is that in standard, or inductive, analogy we support a prediction about a case by comparing it with an actual known case. (For example, one might seek to predict the effects of cyclamate on humans by comparing humans at a certain dosage with rats at what would be a comparable dosage for them. Or one might seek the correct diagnosis of symptoms in one patient by comparing her with another patient known to have had a specific disease.) In such cases, we use actual instances to predict unknown ones, and future experience will show whether we are right or wrong.

1a. A Priori Analogy

With Wisdom’s case-by-case reasoning (or a priori analogy) it does not matter whether the instance used as a basis for comparison is actual or hypothetical, and the reasoning issues in a decision, not a prediction. Consider, for instance, Judith Thompson’s famous analogy between the woman carrying an unwanted fetus and the person who unexpectedly finds herself hooked up to a dying violinist.⁵ The analogue is obviously hypothetical, but this fact does not affect the merits of the argument. Thompson is arguing that the two cases are relevantly similar, so if we grant that there is no obligation to restrict one’s activities to support the life of the violinist, we ought, in consistency, to believe there is no obligation for the unexpectedly and unwillingly pregnant woman to adapt her activities so as to support the life of the fetus. In case-by-case reasoning, as contrasted with inductive analogy, there is no way of taking further measures to find out by empirical observation whether the parallelism suggested here is or is not the case.

In his systematic study of Wisdom’s theory, Bickenbach referred to case-by-case reasoning as ‘reflective reasoning’, following Wisdom’s emphasis. In the present discussion the terms ‘a priori analogy’ and ‘logical analogy’ are used. Because there is reasoning that goes from one case to another and that is inductive, the expression ‘case-by-case reasoning’ does not quite serve to pick out the kind of reasoning Wisdom was dealing with: it is too broad. So too is the concept of reflection.

The thrust that underlies logical analogies is that of consistency – not the consistency required in order to avoid assenting to contradictory propositions, but rather, the consistency required for consistent behavior. This is the consistency of treating relevantly similar cases similarly. It is inconsistent to say that all men are poor listeners while admitting that John and Fred, both men, are good listeners. It is, in another and equally important sense, inconsistent to treat relevantly similar cases differently. If one organism is regarded as alive and another as not alive, there must be a relevant difference between them, at pain of inconsistency. If one man is given three years for theft and another three months, there must be a relevant difference between them, or else the law is inconsistently (and unjustly) administered. Logical analogy focuses on similarities between cases, and arguments based on such analogies urge us to make a decision on a case based on the consideration of a closely similar one. We are pushed to do so by considerations of consistency: similar treatment for similar cases.

The negative use of logical analogy is found in the technique of refuting arguments by citing parallel flawed arguments. If two arguments are fundamentally similar as to structure, and the first is flawed, the second is flawed also. To regard one of the arguments as cogent and the other as not cogent would be to make decisions inconsistently. This is a familiar use of logical analogy. Wisdom, in his lectures, emphasized the philosophical, moral, and legal contexts in which such reasoning is ubiquitous and necessary. The appeal to consistency is also extremely important in law, moral reasoning, and administration.

When he gave the Virginia Lectures, Wisdom seems to have been more interested in reasoning and epistemology – particularly the epistemology of philosophy itself – than he was in argument as such. Nevertheless, it is clear that he thought that case-by-case reasoning was not only a distinct and important type of reasoning but was the basis for a distinct and important type of argument. Any temptation to remodel logical or inductive analogies into deductive or inductive arguments should be resisted, because the type of reasoning such arguments employ is not only a distinct and quite proper type of reasoning but is, in fact, more fundamental than the alternative to which it is to be ‘reduced’. Arguments based on appeals to cases are not reducible to arguments of some other type.

As with other nondeductive arguments, a priori and inductive analogies can be recast as deductively valid arguments, if we are willing to add general premises of a sufficiently sweeping nature. Consider any analogy:

1. (1) Case x has features a,b,c.

2. (2) Case y has features a,b,c.

3. (3) Case x is of type e.
   Therefore,

4. (4) Case y is of type e.

One might regard such an argument as elliptical, insisting that cases (x) and (y) must both be subsumed under the appropriate generalization. Thus:

1. Case x has features a,b,c.

2. Case y has features a,b,c.

3. Case x is of type e.
   Missing Premise: All things which have features a,b,c, are of type e.
   Therefore,

4. Case y is of type e.

But there are significant objections to such an approach.

The added premise makes two of the stated premises redundant as far as the logic of the inference is concerned. If we know that all things with a,b,c, are of type e, then we can apply that universal statement to case (y) directly. We have no need for premises (1) and (3), which cite information about case (x). The comparison of cases is unnecessary. The supplementation makes the key premises which describe the analogy redundant. In effect, the reconstructed argument ceases to be an analogy. A particular (case y) is simply subsumed under a generalization. The analogy has been destroyed, not recast.

In defense of this enthymematic approach to analogy, one might seek to incorporate case (x) into the argument in a purely psychological way, saying that it serves to remind us of the general truth under which case (y) is subsumed. This suggestion still leaves the conclusion that there are no inferences-by-analogy: analogy is purely a psychological crutch. In fact, this view has been taken seriously by some authors of logic textbooks, including Susan Stebbing and Monroe Beardsley.⁶ Nevertheless, given that the generalization must bear the whole weight of the argument, it is rather unsatisfactory to have to admit that a subsumed particular case is psychologically necessary in order for us to remember what that generalization is. We may ask why the generalization is not more directly accessible, if it is known. And the word ‘if’ should be taken seriously here.

The requisite generalization is typically not known and this, indeed, is usually the primary reason for appealing to analogy in the first place. We do compare cases as such, and we can do this in the absence of a known generalization. As W.H. Shaw and L.R. Ashley point out in their article on analogical inference, much familiar reasoning involves the direct comparison of cases without appeal to an intermediate generalization. Ashley and Shaw say:

Alternatively, consider the rich employment of analogies in contemporary ethical writing. Where is the implicit enumerative induction? We do not perform inductions about lifeboat situations, kidnapped kidney donors, trapped spelunkers, out of-control locomotives, or any of the other bizarre cases which moral philosophers spend their time inventing, when we reason analogically from them to the moral situation actually facing us.⁷

Usually, to supplement analogies with universal statements is to distort their logical character and weaken them epistemically: in most cases, those universal statements will not be known. In fact, even to formulate them is often a challenge.

If we knew, somehow, that all reasoning had to be deductive, we would have grounds for insisting that such reconstruction of a priori analogies is necessary. But we do not know this, and we have no such basis. Analogies are, and should be, appraised not by formulating and criticizing generalizations, but by careful consideration of the relevant similarities and differences between the cases considered. This point holds for both a priori and inductive analogies. (Wisdom, as explained, was emphasizing the former over the latter.)

In Moral Scepticism and Moral Knowledge, Renford Bambrough defends Wisdom’s claim that reasoning about cases is logically prior to reasoning by the application of universal claims or rules. If a case is to be settled, and we try to settle it by deducing a conclusion from a universal rule, the epistemological problem is that the universal rule already includes a resolution of this case. Bambrough says:

Once we are convinced that there will be no exceptions we may state our conclusion in the form of an exceptionless rule, but such a rule cannot be the fundamental ground upon which we accept a conclusion about one of its own instances. Whatever is to provide us with grounds for a conclusion about this instance of an argument in this form must take the form of considering other arguments, other instances. A rule will not do the work, for a rule cannot refer to the others without referring to this one as well. It does not compete, but simply awards itself the prize.⁸

Here, Bambrough turns the tables on those who would make individual judgments about cases dependent on universal or general rules. He sees general rules as arbitrary considered simply in themselves and as gaining their credibility (implicitly or explicitly) from their correct application to instances. On this analysis, Bambrough follows Wisdom in thinking that cases can stand alone. Mill, Moore, and Wittgenstein also accepted this. But it is a minority position in philosophy. Philosophers have usually been inclined to have universal principles stand alone as ‘self-evident’ logical or moral truths.

1b. The Universal and the Particular

The issue raised here is whether the universal or the particular is logically prior. We may say, with Wisdom, Moore, and Bambrough, that nothing can have greater force than a clearly understood particular case, and that what universal truths we know are in one way or another derived from our knowledge of such cases. Or, as is more common in a generalizing and theorizing discipline, we may regard particular cases as epistemically incomplete, as being mere expressions of intuition or common sense unless ‘grounded’ in universal principles. In fact, this general issue itself may be stated in a way that is too insensitive to particulars. Perhaps the truth is that what is epistemically prior varies from case to case and from context to context. But at the very least we can find in Wisdom and Bambrough, as in Mill, Moore, and Wittgenstein a useful, reminder that arguments from universal premises are not without their epistemic problems.

Despite their insistence that analogical inference is a distinct type, Shaw and Ashley take the opposite view to Wisdom’s about particulars and universals. They see the general as more fundamental than the particular and urge that a full understanding of relevance and irrelevance depends on background theory. On their account, a full understanding of the cases compared in an analogy will ultimately require a background theory, in which we are told why certain features a,b,c are relevant to the judgment that cases x and y are of type e. Shaw and Ashley allow that analogies, both a priori and inductive, constitute a distinct type of argument. They acknowledge the epistemic difficulty of formulating and knowing the requisite generalization for remodelling the arguments. And yet they see the appeals to relevant similarities on which analogies depend are theoretically incomplete.

Consistency is a basic constraint on human reasoning, and we must at the very least judge similar situations similarly …. even in the absence of a clear notion of relevance, the resemblance of two situations provides some warrant for the inference that what is right in one case is right in the other. But this may be thought to beg the question. Do we not need a theory to designate the relevant and irrelevant similarities? Ultimately yes. But in the meantime we have, prior to any particular normative theory, a perception of two situations as similar, and this is enough (along with our commitment to consistency) to provide some intrinsic plausibility to the analogical move.⁹

Wisdom would have regarded such a view as symptomatic of ‘Euclid’s disease’, an ailment he and Wittgenstein diagnosed in those who disparage particular cases and regard universal knowledge, by ‘criterion’ or general reason, as the only knowledge. He saw judgments about the relevance and significance of features of individual cases and resemblances between those features of cases as being ultimate, and as not requiring or being amenable to further justification by appeal to anything more basic. According to the manuscript of the Virginia Lectures, Barker asked Wisdom why it was that the particular case always had more epistemic force than a universal that might be cited in support. In raising that question, Barker suggested that each might have force and, in some context, require revision of the other. Barker, in effect, anticipated a version of Rawls’ influential view that we seek ‘reflective equilibrium’ between theoretical principles and nontheoretical judgments about particular cases. In response, Wisdom reiterated the predominance of the particular as a ground for generalization, saying:

What most plainly presents the data on which the rest is based is the argument from particulars to particulars.¹⁰

Following Wisdom, Bickenbach contended that a major symptom of Euclid’s disease is the belief that systematization is a precondition for genuine or complete understanding.¹¹

Whether the judgments about the relevance of various similarities and differences that underlie our evaluation of analogies are in some ultimate sense theory-dependent is a broad philosophical issue that cannot be resolved here. The notion of reflective equilibrium between theoretical and case judgments has been applied by Goodman to deductive and inductive logic and by Rawls and others to ethical and political theory. It requires that both particular judgments about cases and theoretical principles have some initial credibility. Sometimes it is reasonable for us to revise our pre-theoretical judgments about individual cases on the basis of principles; sometimes, we seek to build up theoretical principles on the bases of knowledge of cases. We may revise principles if they do not fit our judgments about particulars that would be subsumed under them. We may also revise our judgments about cases according to principles that we have accepted. Thus principles and case-based judgments must each be adjusted in the light of the other.¹²

Even if the disputable view that the general is always logically prior to the particular were to be true, the pertinent background theories often do not yet exist. In the meantime, it is clear that analogies, both a priori and inductive, have a real epistemic use.

Hume’s Dialogues on Natural Religion contain many vivid illustrations of arguments of this type. Consider, for instance, this example:

The Brahmins assert that the world arose from an infinite spider, who spun this whole complicated mass from his bowels, and annihilates afterwards the whole or any part of it, by absorbing it again and resolving it into his own essence. Here is a species of cosmogony which appears to us ridiculous because a spider is a little contemptible animal whose operations we are never likely to take for a model of the whole universe. But still, here is a new species of analogy, even in our globe. And were there a planet wholly inhabited by spiders (which is very possible), this inference would there appear as natural and irrefragable as that which in our planet ascribes the origin of all things to design and orderly system and intelligence, as explained by Cleanthes. Why an orderly system may not be spun from the belly as well as the brain, it will be difficult for him to give a satisfactory reason.¹³

This argument is an a priori analogy between two arguments; the spider’s argument that the world has been spun from the bowels of an infinite spider is compared to the human’s argument that the world has been designed by an infinitely expanded human mind. Hume invites us to see the second argument as being as ridiculous as the first.

Apart from Hume, other prime philosophical sources for a priori analogies include Robert Nozick’s Anarchy, State, and Utopia, and Stanley Cavell’s The Claim of Reason. Given that this technique of arguing is common among philosophers, it is surprising that it has not received more attention from theorists.

Such analogies are common, not only in philosophical thinking about moral problems, but in ordinary non-philosophical thinking as well. Nor is this kind of reasoning restricted to the moral realm. It is also used in conceptual and interpretive contexts, by philosophers and others. Consistency reasoning is prominent in law, especially in the common law system where cases may be resolved by appeals to precedent. Even where there are explicit statutes, constituent terms are interpreted according to their prior application to cases. The core of legal reasoning is, as Wisdom noted, case by case. The appraisal of such reasoning requires careful attention to the similarities and differences between the cases, and a judgment as to how relevant these similarities and differences are to the decision at hand.

A type of argument of obvious prominence and importance has been widely ignored by theorists. Probably this is due to the fact that it is less prominent in science and in mathematics than in moral life, law, administration, criticism, and philosophy. Philosophers have tended to construct theories of knowledge and argument as though positivism were true.

Case-by-case reasoning as Wisdom describes it is not itself amenable to extensive theoretical analysis. Case-by-case reasoning is recalcitrant to treatment by general rules, because we cannot say in general what cases are going to be similar and why. This may lead us to think that endorsing it will lead inevitably to scepticism or relativism. But no such consequences follow.

In isolation from information about which cases are at issue and why they are being compared, what may be said? One possibility is to explore further cases. If two cases are deemed to possess feature e in virtue of other features a,b,c then that implies that the features a,b,c, function to establish e, other things being equal. This relationship should hold in general. If we find a third case in which the relationship does not hold, we then must seek further to see how that case might undermine the basis of the analogy. It might turn out that the new case differs from the original analogue with respect to some feature f and that it is f which undermines e. If so, the original analogy tacitly depended on the two compared cases both lacking feature f. By a close examination of relevantly similar and relevantly different cases, we can rationally adjudicate differences of belief as to whether comparisons are apt and whether particular similarities and differences are significant.

It is an open question as to whether we can set out a general ‘logic’ for appraising a priori analogies. Wisdom and others following him tend to write as though this could not be done. Their opinion has probably been shared by systematic logicians, who have always found analogy less interesting than deductive reasoning and empirical inductive reasoning. Whether a set of rules for the comparing and contrasting of cases can be devised remains to be seen. But even if it cannot, this would not entail that case-by-case reasoning fails to exist at all. Whether or not such reasoning is recalcitrant to systematization, it is real.

My point, like Wisdom’s, is not merely descriptive. It is normative as well. Case-by-case arguments, or a priori analogies, are both real and epistemically legitimate. I would urge that some such arguments are good ones and can establish a conclusion. Though rules may not exist to resolve disputes about the merits of these arguments, there remains room for rational debate and reasonable resolution. Similarities and differences can be pointed out, and the significance of these can be rationally discussed.

To the Euclidean theorist who is not satisfied with such a response, we can reply by turning the tables. Rules and generalizations do not stand independently. They themselves ultimately require justification, and in the final analysis will receive it from their application to cases.

2. Carl Wellman and the Concept of Conductive Argument

Do philosophers prove by chains of demonstrative reasoning what they wish to say or without attempting to support in any way one thing by another, just set out the self-evident or what appears to them self-evident? This question gives one a queer feeling because one wants to answer that they do both and neither … It is true that, when we read, for example, Hume’s appendix on the analysis of right and good or Broad on theories of the nature of matter, we find that a number of what Mill might call ‘considerations capable of influencing the intellect’ are advanced. But they are not connected chainwise. They bear independently upon the issue.¹⁴

Carl Wellman’s Challenge and Response was ostensibly about meta-ethics, but in fact dealt largely with the subject of justification in general. Wellman devoted much time and care to discussing the question ‘What is justification?’, and had some rather unorthodox things to say in reply. He summed up his view as follows:

… justification is to be understood essentially as a process of responding to challenges made. It may be observed and described as a psychological struggle in which one person tries to force another to back down, or one person struggles to come to terms with his own doubts and conflicting convictions. But it is more than a psychological struggle because at its core are certain critical claims to truth, validity, to be upsetting, to be reassuring, and to be adequate. Therefore the actual outcome of any particular psychological struggle never settles once and for all the issues being fought over in the process of justification. It is this peculiar ambivalence of justification that enables what we actually do in discussion and thinking to serve as a test of critical ideas like truth, validity, and being justified.¹⁵

Much justification proceeds by argument and Wellman said some interesting and unusual things about arguments in his book.

Wellman argued that the inductive/deductive dichotomy is not exhaustive and that there is at least one other type of argument, which he termed ‘conductive’. Wellman’s definitions of ‘deductive’ and ‘inductive’ are somewhat unusual. He defines deduction much as Copi does: a deductive argument is one in which the claim is made that the conclusion follows necessarily from the premises. In ethics, which is his primary concern, Wellman associates deduction with deriving conclusions about cases by subsuming the cases under general principles. Induction according to Wellman, is that sort of reasoning by which a hypothesis is confirmed or disconfirmed by establishing the truth or falsity of its implications. Conduction, a third type of reasoning, is distinct from both deduction and induction, being that sort of reasoning in which (1) a conclusion about some individual case (2) is drawn nonconclusively (3) from one or more premises about the same case (4) without any appeal to other cases. In conductive reasoning where there are several supporting premises, we draw together these independently relevant factors to support a conclusion. A conductive argument, then, depends crucially upon the concept of relevance. It differs from a deductive argument because the factors cited do not entail, and are not put forward as being sufficient for, the conclusion stated. It differs from an inductive argument in that it is not a case of confirming or disconfirming hypotheses by instances and in that (typically) separately relevant reasons are cited in support of a normative, conceptual, or philosophical conclusion. The issue is frequently not empirical.

Wellman sought to establish this third category of argument in order to show that there is more flexibility than most of us suppose in the matter of justifying conclusions. He was especially concerned to combat the common view that justification in ethics must be a matter of deriving particular conclusions from universal or general principles. On Wellman’s account there are at least three different types of ethical reasoning, all of which are used to justify conclusions about what we should do. First, we may deduce such conclusions from general principles, in cases where we are certain enough of such principles to use them in this way. Second, we may confirm or disconfirm general hypotheses using judgments about particular instances, thus reasoning inductively in Wellman’s sense. Third, we may support a conclusion about a particular problem by citing a fact or several facts that are nonconclusively relevant to it.

Suppose one says, ‘You ought to take your son to the movie because you promised to do so, it is a good movie, and you have nothing better to do this afternoon’. One is reasoning conductively to a conclusion about what to do.

Wellman’s discussion may appear less generally interesting than it is due to his contestable accounts of deduction and induction. There are problems with defining deductive arguments in terms of ‘claim to necessary connection’; in many arguments there is just nothing to indicate whether such a connection is claimed or not. Furthermore, Wellman unnecessarily limits himself to deduction from the universal to the particular. Obviously, there are other forms of deduction. Then again, Wellman’s definition of ‘induction’ is highly idiosyncratic, as he recognizes himself. One might maintain that it is useful to have an account which allows for induction in a priori contexts. A problem arises because many modus tollens arguments, which are deductively valid, will count as inductive in Wellman’s sense. Consider, ‘If all my students are computer science majors, then since Joe is my student Joe will be a computer science major. But Joe is not a computer science major. Therefore the hypothesis that all my students are computer science majors is incorrect’ is an argument in which a hypothesis is disconfirmed by an instance. It is inductive according to Wellman’s definition. But obviously it is deductively valid. And it could be claimed to be deductive in Wellman’s sense too – it can easily be regarded as ‘claiming’ deductive validity. Wellman’s notion of induction is too broad because it will include some deductively valid arguments to count as inductive. But it is also too narrow, given that causal reasoning, reasoning to the best explanation, and reasoning from generalizations based on past experience to a future case will not count as inductive in this sense. These results are highly (and unnecessarily) counter-intuitive. With such an unorthodox concept of ‘induction’ the claim that there is a distinct type of non-deductive and non-inductive reasoning may appear to be no more than the result of an unorthodox classificatory system.

As Wellman noted, but did not emphasize, conductive reasoning is not restricted to ethical contexts. It is common in contexts where we are trying to reach a decision about a classificatory issue, in interpretive contexts, and in contexts of philosophy and theory. Arguments that are conductive typically bring forward several relevant factors in the premises. It may happen that only one non conclusively relevant factor is cited; in this case, the difference between the conductive argument and a deductive one is that the factor is not sufficient and other factors, not mentioned, could have been mentioned to count as well.

Also, conductive argumentation is a favoured context for ‘pros’ and ‘cons’ in arguing. We may allow that there are factors relevant to the conclusion that count against it, mention these in the argument, and then cite supportive factors for the conclusion. We judge, and ask our audience to judge, that the supportive factors outweigh the counter considerations.

Consider, for example, the following interpretive argument:

Hume is not a sceptic, for although he argues that our basic beliefs are not rationally justified, he rails against classical sceptics, and he maintains that we are as much determined to believe as we are to think and feel.

This is a conductive argument of the ‘pro and con’ type. One factor is cited which would count towards Hume being a sceptic, and two other factors are cited which would count against that view. The latter two factors are deemed to outweigh the first one so that the argument overall presents good reason to believe that Hume is a sceptic. Much actual reasoning seems to involve this kind of consideration of pros and cons, and estimating or ‘summing up’ their collective significance. A conductive argument may be the product of such reasoning about pros and cons. It will typically involve the specification of several such factors and adduce a conclusion on the basis of what the arguer takes to be their cumulative force. Such arguments had been tacitly recognized by other writers.

2a. Related Views

Kurt Baier’s emphasis on ‘good reasons’ arguments in ethics is one case in point. In The Moral Point of View, first published in 1958, Kurt Baier described the variety of reasons available to justify moral conclusions, and seems to have had something like conductive arguments in mind. He said:

To say that a certain fact is a consideration, a pro or a con, is to say that this fact gives rise to a presumption, namely, that the agent ought or ought not to enter on the course of action in relation to which the fact is a pro or a con. Exactly the same point is made when it is claimed that some reasons are prima-facie reasons, or reasons other things being equal. All that is meant is that the facts which are the reasons give rise merely to a presumption that the agent ought or ought not to enter on the line contemplated.¹⁶

Both Michael Scriven and Stephen Thomas noted the existence of arguments in which distinct factors cumulate, or converge, to support a conclusion. However, in neither case was there much discussion of such arguments as a distinct type.¹⁷ Thomas, in fact, incorporated theorizing inconsistent with the claim. As a result of my critical notice in the Informal Logic Newsletter, calling attention to Wellman’s account and arguing for its significance, David Hitchcock incorporated a recognition of conductive arguments in his textbook. In general, however, Wellman’s account did little to upset philosophers’ confidence in deductivism and positivism as theories of ordinary argumentation.

The notion of conductive argument does not owe its interest solely to Wellman’s somewhat idiosyncratic classificatory system. The idea that in many arguments the basic notion is that of nonconclusive relevance and that such arguments readily incorporate ‘pro and con’ considerations is important and had been explicitly or tacitly recognized by other analysts. What I should like to do here is endorse Wellman’s ideas about relevance and pros and cons and drop some other features of his account. I do not wish to endorse his definitions of ‘induction’ and ‘deduction’, nor his limitation of conductive reasoning to contexts where a particular conclusion is defended. Wellman made conductive arguments by definition about particular cases. But this seems unfortunate, as it is easy to think of examples where separate facts are cited to nonconclusively support generalization. Consider, for instance:

Blacks are equal to whites because they are as healthy as whites, they are biologically similar to whites, they are as intelligent as whites, and they share basic needs with whites.

Whatever the substantive merits of this argument, we can readily see that it is based on separate nonconclusively relevant premises. It is the sort of argument where ‘cons’ could be acknowledged and ‘weighed’ with the ‘pros’. The various premises about blacks and whites are separately relevant to the conclusion in the sense that if one were false, the others would remain unaffected. Thus the example fits much of what Wellman has to say, and yet the conclusion is not particular in form. Clearly, we may reason about cases by citing relevant factors, and in addition, much conductive reasoning is about cases. However, conductive reasoning may also be used to support conclusions that are general or universal in form.

Conductive argument and a priori analogy are distinct types. Wellman says that in conduction the link between premises and conclusion is not established on the basis of the experience of analogous cases; it is entirely a priori.

Conductive reasoning and Wisdom’s case-by-case reasoning fit into a similar gap unnoticed by many who have supported deductivist and positivist theories of argument. Both deal with nonempirical reasoning that is nonconclusive, or at least not ‘conclusive’ in the deductive sense. Conductive arguments require separately relevant non-sufficient factors and readily admit counterconsiderations as part of the argument; a priori analogies use comparison of cases to press for consistency of treatment, and depend fundamentally on the concept of relevant similarity.

To clarify the contrast between conductive arguments and others, it is useful to refer to different ways premises may combine to support conclusions in multi-premise arguments. These different styles of support have to do with the structural arrangement of premises, and not with the strength or character of the support those premises are able to give to a conclusion. Nor do they concern the truth or plausibility of the premises. They concern the diagramming of arguments, not their classification or inferential appraisal. The classic accounts of this style of support are Beardsley’s early text and Thomas’ text on reasoning in natural language. The latter is justly famous for its exposition of structure and adaptation of Beardsley’s techniques. The distinction presented is between convergent and linked argumentation.¹⁸ When the pattern of support is linked, one premise is not even relevant to the conclusion without the others. In a convergent support pattern, premises bear separately upon the conclusion. All conductive arguments exemplify the convergent pattern or support, except in the limiting case where there is only one premise. However, the converse does not hold, as Wellman was careful to note. It is possible to offer an argument which exemplifies the convergent support pattern, in which there are several different premises, each of which, taken alone, deductively entails the conclusion. This situation may occur either because the arguer expects that some of his premises will be contested or because he is not aware that the entailment relationships hold and make some of his premises logically redundant. He offers more reasons than are logically required. In a conductive argument, the premises strengthen each other as support, even when they are not in question: ‘it is the logical force, not the probative force, of the argument that is increased with the addition of each new premise’, Wellman says.¹⁹

We cannot define conductive arguments solely with reference to the convergent support pattern, because if we were to do so, some deductive arguments would be conductive. There is a similar problem with induction. Some inductive arguments use the convergent support pattern, particularly if a number of distinct, and apparently unrelated cases, are cited to support a generalization. Typically, in a conductive argument no one premise deductively entails the conclusion. Nor do the premises entail the conclusion when considered together. The premises count in favour of the conclusion in the sense that they are, or are taken by the arguer to be, positively relevant to it. Here ‘relevant’ does not mean ‘sufficient.’ The method by which we assess a conductive argument is not to test for deductive validity. Rather, it is to ask ourselves whether the premises are relevant, how much support they give to the conclusion, and whether unmentioned factors that are also relevant to the conclusion would ‘outweigh’ the premises. We may also consider further cases to test claims of relevance. The conclusion is not a generalization from cases, as it would be in an enumerative induction. Nor does it presume empirical regularities among considered cases or the kind of background empirical knowledge needed for explanatory or causal inductive reasoning. Whether X is relevant to Y, in these contexts, is a conceptual, normative, or ‘criterial’ issue.

A priori analogies, like all analogies, employ the linked pattern of support. They are of the general type:

1. X has features a,b,c.

2. Y has features a,b,c.

3. X has feature e.
   Therefore,

4. Y has feature e.

The premises link to support the conclusion, as they do also in the more schematic version of analogy:

1. X is similar to Y.

2. Y has feature e.
   Therefore,

3. X has feature e.

Wisdom dealt with analogy arguments in which support is linked and reasoning moves from a point about one case to a conclusion about another. Wellman deals with arguments in which the support is convergent and connections are by criterial relevance, not comparison. Thus we must have two types, not one.

2b. Further Examples

Since Wellman’s main concern was with the justification of ethical propositions, he gave examples primarily from the domain of moral reasoning. But this restriction is not essential; examples dealing with many subjects can be found. Here is one, cited by Scriven.

We can be proud that America has turned the corner on the depression of the last few years. At last the many indexes of recovery are showing optimistic readings. The rate of inflation has slowed, unemployment has more or less stabilized, inventories are beginning to drop, advance orders are starting to pick up, and – the best news of all – the average income figures are showing a gain. The doomsayers have been discomfited, and the free enterprise system once more vindicated.²⁰

Here, a number of distinct pieces of evidence are cited to support the proposition that America is recovering from the depression: slowing of the inflation rate, stabilization of unemployment, increase in advance orders, and gain in average income figures.

An example from the field of literary criticism is the following:

There can be no doubt that Emily Bronte cast a vague incestuous aura over the entire plot of Wuthering Heights. Heathcliff marries his lost love’s sister-in-law; his wife’s son marries her brother’s daughter; Cathy’s daughter marries her brother’s son. An unconsciously incestuous love between the two leading characters would not run counter to the tone of a novel filled with violent and savage scenes, such as the sadistic rubbing of a wrist over a broken window pane, Cathy’s fierce delirium, or the sight of Heathcliff smashing his bloody head against a tree.²¹

Here, four separate premises are given to support the conclusions that there is an incestuous element in the novel: three specify quasi-incestuous relationships, and the fourth cites other violence, claiming that the savage mood of the novel is such that incest would not be out of place. A conductive argument is used to support an interpretive claim.

We can also find examples of conductive arguments within philosophy. Consider, for instance:

We found that either (a) the corresponding sense-datum is usually not identical with the observed surface of the object or (b) the corresponding sense-datum usually lacks the qualities it is sensed as having. For (1) the qualities which it is sensed as having are usually incompatible with the qualities of the surface: and (2) the qualities which different observers sense their corresponding sense-data as having are usually incompatible with one another.²²

The conclusion is the disjunction of (a) and (b); statements (1) and (2) constitute separately relevant premises. That sensed qualities are usually incompatible with those on the surface of the object and that sensed qualities, as sensed by different observers, usually differ and are incompatible, are two distinct claims put forward as support for the conclusion. Neither entails it; both are conceptually relevant to it.

Another philosophical example, this time incorporating counter considerations, is:

That ‘this exists’ has any meaning in such cases, where, as Mr. Russell would say, we are using ‘this’ as a ‘proper name’ for something with which we are acquainted is, I know, disputed; my view that it has involves, I am bound to admit, the curious consequence that ‘this exists’ when used in this way is always true, and ‘this does not exist’ always false; and I have little to say in its favor except that it seems to me so plainly true that, in the case of every sense-datum I have, it is logically possible that the sense-datum in question should not have existed – that there should simply have been no such thing.²³

The conclusion is that ‘this exists’ has meaning. There is one major reason advanced for it: ‘this’ names a sense datum (understood as part of the background and context) and it is logically possible that any particular sense datum should not have existed. It is acknowledged that there are two points counting against the conclusion. One is that ‘this exists’ will always be true. The other is that ‘this does not exist’ will always be false. The author (G.E. Moore) makes it clear that the single pro factor outweighs the cons in his judgment. (He does not tell the audience why he thinks this.) My point here is not that Moore’s argument is a good one, or even that it is a clear one. The point is that it is a philosophical argument that is conductive in type.

I have noticed a tendency among beginning students in practical logic to approach arguments in a way which is inappropriate for standard deduction and induction. Students often seem to believe that the more premises an argument has, the better it is. They find it almost impossible to believe that a perfectly cogent argument may have only one premise. Furthermore, asked to assess the connection between premises and conclusion, they will often begin by looking at the premises one at a time, to try to determine, for each premise, whether it is relevant to the conclusion and what support it might offer. Such preconceptions are often incorrect, but they are appropriate for conductive arguments. It is likely that their prevalence among beginners is a kind of testimony to the presence, in ordinary argumentation, of many conductive arguments in which various reasons are offered to support a claim.

There is a tendency in some philosophical circles to want to reduce conductive arguments to deductive ones. The standard strategy is available here: we regard conductive arguments as being enthymematic. Wellman spends some time rejecting this approach and offers a splendid account. Briefly, the major objection is that if we try to turn such an argument as ‘you should return the book because you promised to do so’ into a deductively valid argument, we will need an additional premise, deemed, of course, to have been ‘missing’ in the original. But candidate added premises will turn out to be either false, unverifiable independently of a judgement about the case in question, or impossible to formulate in advance. That you should always keep promises is false; that you should always keep promises other things being equal is unverifiable independently of a judgement about the case at issue; that you should always keep promises in circumstances of type (abc) is impossible to formulate in advance. The enthymeme approach, here as so often, makes an inference watertight at the cost of introducing an unknowable premise. Wellman denies

that such reformulated arguments can be used to justify ethical conclusions in the way that their originals can. This is because one is often not in a position to justify the premises that must be added to make the arguments deductive in form. Since I believe that arguments really do, at least in some cases, justify the conclusions drawn from them, I conclude that it is a mistake to try to save deductivim by trying to find additional premises.²⁴

Proposed additions are likely to distort the original argument, which is typically not put forward as being conclusive, and make the merits of the argument impossible to determine. If one adds a premise with an ‘other things being equal’ clause, then in order to determine whether this premise applies to the case at issue, one will have to make a prior determination of the case. (Thus the deductive reasoning is not what is providing the answer.) In a case where several premises appear, the problem is even worse, because one argument is turned into several, each ‘conclusive’ from an inferential perspective and having an unknowable premise.

Like Wisdom, Wellman insists that we can and do reason about particulars without relying on linking generalizations. Such a position, though a minority one within philosophy, has a venerable history, and was clearly put by Descartes. When Descartes introduced the Cogito, some critics argued that ‘I think therefore I am’ was really a syllogism, with the missing premise ‘Everything that thinks exists’. Descartes denied it. ²⁵

He who says, I think, hence I am, or exist, does not deduce existence from thought by a syllogism, but, by a simple act of mental vision, recognises it as if it were a thing that is known per se. This is evident from the fact that if it were syllogistically deduced, the major premise, that everything that thinks is, or exists, would have to be known previously; but yet that has rather been learned from the experience of the individual – that unless he exists, he cannot think. For our mind is so constituted by nature that general propositions are formed out of the knowledge of particulars.

In a letter, Descartes anticipated some of Wisdom’s themes when he said:²⁶

... But the greater error here is our critic’s assumption that the knowledge of particular truths is always deduced from the universal propositions in consonance with the order of the sequence observed in the syllogisms of the dialectic. This shows that he is but little acquainted with the method by which truth should be investigated. For it is certain that in order to discover the truth we should always start with particular notions, in order to arrive at the general conceptions subsequently, though we may also in the reverse way, after having discovered the universals, deduce other particulars from them.

When Descartes said that ‘everything that thinks exists’ would have to be ‘learned from the experience of the individual’, he did not mean to say that the premise is empirical, but rather that we are able to know it because we have had insight, in one or more particular cases, into the logical connection between thinking and existence. The idea that the universal may be known in and through the particular is also prominent in Aristotle’s theory of knowledge.

There is no good reason for the belief that all particular inferences require supplementation with universal premises. Such a view ‘clarifies’ arguments logically only by weakening them epistemically. The logical structure in which a particular case is resolved by being subsumed under a generalization is, indeed, simple and lucid. But its logical elegance masks epistemic weakness: all too often that generalization is one we do not or cannot know. There is no sound basis for insisting that all conductive arguments be recast as deductive ones in which cited factors are linked to the conclusion by supplementary universal premises.

3. Cases, Relevance and Rules

Neither conductive reasoning nor case-by-case reasoning is fully amenable to treatment by general rules. Perhaps it is for this reason that these kinds of reasoning have been so widely ignored by logical and philosophical theorists. There seems little scope for theory construction and research projects. So far, theorists have done little more than make some rather general comments about their appraisal. How much systematization is possible remains in doubt. Those who insist on general rules as a presumption of correct argumentation will find this situation disturbing. These arguments quite certainly exist although the rules that are allegedly required do not seem to. It is often alleged that any judgment of merit – whether in the domain of logic or elsewhere – is based on a rule. With no rule, there can be no sound or unsound, no valid or invalid, no better or worse. If that claim were true, we might have to admit that there can be no critical discrimination for a priori analogies and conductive arguments. Their existence would make at best a negative contribution to logic and epistemology.

There is a discussion of this view in Wellman’s book.²⁷ He counters it by citing an independent basis for judgment as what is necessary for objective content and then remarking that there is at least some sense (a weak one) in which this condition can be met in the case of arguments for which there are no generally application rules of validity. That is, ‘Argument A is sound’ will admit of truth or falsity if there is something relevant to its truth apart from our believing in it. This condition can be met to some extent, even in the absence of a general rule. If we think about A and find its premises relevant to its conclusion, and sufficient for the truth of that conclusion, this does not itself guarantee that they are so. We have a way of checking up on whether we are right. This is, on Wellman’s account, to ‘think it through again’. Judicious and careful reflection on the matter can make us change our mind. We do this and find it pertinent. We do sometimes change our minds, and we are sometimes quite certain that we were right to do so.

Is this all that can be said? Perhaps not. The issue will hinge on two further ones: first of all, whether judgments of relevance can be rationally adjudicated, and secondly whether the ‘weighing up’ of factors is subject to any general principles of method. It has been suggested that judgments of relevance can be tested by bringing factors to bear on other cases. (For instance, if equality of distribution counts for justice in consideration of property, it ought similarly to do so in contexts of punishment or reward.) Another possibility is that procedures might be sought for assessing the significance of pros and cons. These possibilities need exploration. Wellman may not have taken this matter as far as it can be taken. However, even if he is right about the limitations of rules in contexts of conductive argument, this limitation would not show either that the arguments fail to be a genuine type or that they are never logically cogent.

The same can be said for analogies. We may find an analogy striking and convincing and then, on reflection, spot a key difference between the cases that is relevant to the point and decide that the analogy is faulty after all. Or a scrutiny of further comparable cases may reveal the significance of other factors we had not noticed at first. Such processes are not as elegant and person-independent as the application of a formal or general rule, but it exists and is more than nothing.

Theories of reflective equilibrium require that sometimes judgments about particulars have to stand as a check on rules. This requirement presupposes that there is such a thing as logical adequacy in the absence of rules. To serve as a check on a rule, as much current theory in linguistics, science, and ethics requires, a judgment about a particular case must have its own logical credibility which is not dependent on a rule.

For a number of reasons, Wellman rejects the view that validity must be formal and must be demonstrable by appeal to formal rules. Prominent among them is the ultimate dependence of formal rules on nonformal, extrasystematic judgments of validity.²⁸

(S)urely the existence of valid reasoning does not presuppose the existence of any such calculus of derivation rules, for the inferences formalized by Hilbert and Ackerman, say, were valid before they invented their logical system, just as the syllogism was valid long before Aristotle. As a rule, the logician tries to construct his calculus so that it will reflect some sort of reasoning that is recognized to be valid independently of his system. To be sure, the inventive logician can think up queer logics which suggest new, and sometimes strange, ways of reasoning. But if these queer logics become too queer, they are no longer considered logics, but only symbolic games of some similar sort. This indicates that even here, our standards of validity arc outside and independent of the derivation rules in any uninterpreted calculus.

This kind of point has been strongly emphasized by such theorists of formal logic as Arthur Pap and Susan Haack. Validity is not by definition formal validity, and legitimate connections between premises and conclusions need not be formally appraisable in order to be real. The absence of formal, or even general accounts does not rob critical judgments about such arguments of all content.

Suppose we were to have a background theory pertinent to a specific argument. The theory might, for instance, include laws, principles, or rules explaining the relevance relations on which both conductive and case-by-case reasoning ultimately depend. Surely such a theory would be useful in evaluating the argument. Ashley and Shaw pressed this point of view in their article on analogy, and it might be extended to conductive arguments as well. It is not comfortable to be left insisting that something just is relevant and something else just is not relevant. To defend our judgments, we have to try to explain connections: a well-established theory would help to do that. Insofar as general theories are obtainable, they can help to buttress these arguments. Such background theories may be empirical, normative, or conceptual; what matters is that they cover the phenomenon in question, and be widely accepted and well-confirmed.

Granting this belief, one might be inclined to see analogies and conductive arguments as temporary crutches needed only in a time of incomplete knowledge. That seems to be the direction of Ashley and Shaw’s account. Analogies would not be necessary if we had general knowledge about all the things that interest us. Since we don’t, they are, according to these authors.

I submit that such a view is not plausible. It ignores the dependence of theoretical principles on particulars. Furthermore, it neglects the key role of analogical reasoning in language learning and use. No amount of theory could entirely avoid the need for a priori analogical reasoning. To determine whether a new case should be subsumed under a law or principle of the theory we would have to compare and contrast that case with others so subsumed. We would still create and learn language by tacit assimilation of relevantly similar cases. We would still seek consistency in logic, law, ethics, and administration. Case-by-case reasoning is a key stage in establishing theoretical principles and remains a key stage in applying these once they are established. It is not doomed to extinction by prospective all-encompassing theories.

A similar point can be made about conductive argumentation. All current accounts of theory acceptance specify several distinct conditions as relevant to the merits of theories. If empirical, they must be well confirmed; they must have explanatory value; they must be consistent with established theories; they must have predictive power; they must be simple; they should have research potential (be ‘fruitful’). Different philosophers of science vary the list and have varying interpretations of what the items on it mean. But all agree that there is more than one item on that list. Competing theories will almost always measure up differently on different criteria. Thus an argument for the acceptance of a theory is bound to be a conductive argument. Comparable comments can be made about normative theories: there is more than one desideratum and competing theories will satisfy these differently. For moral theory we want sensitivity to considered judgments; coherence; ready teachability; and ease of application.

Meta-theoretical arguments about the various merits of competing theories will be largely conductive. In addition, after normative and empirical theories are accepted, novel cases not handled by the theories are bound to arise. These will not be fully covered by existing principles, and we will have to deal with them as best we can: by specifying various relevant factors and seeing how they add up, or by comparing and contrasting new cases with standard ones. That means using conductive reasoning and defending our conclusions with conductive arguments. No amount of theory is going to eliminate the need for these.

As nondeductive, a priori, and particularistic ways of arguing, a priori analogy and conduction are real and important. They are not about to disappear. I believe that much of what Wisdom and Wellman had to say is true. Their work gives us significant additions to epistemology and the theory of argument.

Notes

1. John Wisdom, ‘Explanation and Proof’, Lectures presented at the University of Virginia, 1957, manuscript. I am grateful to Professor Wisdom for giving me permission to read this manuscript and to Roger Shiner for lending me his copy.

2. Carl Wellman, Challenge and Response: Justification in Ethics (Carbondale: Southern Illinois University Press, 1971). See also Trudy Govier, ‘Critical Notice of Carl Wellman’s Challenge and Response’, Inform~1 Logic Newsletter Vol ii, 2 (April, 1980), pp. 10-14.

3. These lectures have not been published, but a transcript prepared by Prof. S.F. Barker is in limited circulation.

4. Renford Bambrough reports that they may eventually appear in print. See also chapters 3, 4, 6, and 7 in Philosophy and Psychoanalysis (Oxford: Blackwell, 1953; chapters 6, 8, 10, and II of Paradox and Discovery (Oxford: Blackwell, 1965); and ‘Moore’s Technique’, in The Philosophy of G.£. Moore edited by P.A. Schilpp (LaSalle, Ill.: Open Court, 1942; Volume II), pp. 419-450. 5. See Bambrough, Op. cit., and D.C. Yalden-Thomas, ‘The Virginia Lectures’, in Bambrough (editor), Wisdom: Twelve Essays. (Oxford: Blackwell, 1974.) It was W.A. McMullen who first interested me in Bambrough’s work. For relevant discussions of case-by-case reasoning, see Harrison, Frank Russell II, ‘Concerning the Possibility of a General Theory of Analogy’, University of Virginia, 1961; Arnold B. Levison, ‘Proof and the Case-by-case Procedure’, University of Virginia, 1959; Jerome Bickenbach, ‘The Nature and Scope of Reflective Reasoning’, University of Alberta, 1977. Compare also J. Bickenbach, ‘Justifying Deduction’, Dialogue Vol. XVIII, No.4 (December 1979), pp. 500-516 and ‘The Diversity of Proof, Informal Logic Newsletter, Vol iv, 2 (May, 1982), pp. 7-12. A case somewhat similar to Wisdom’s, but with a different emphasis has been developed recently by F.L. Will. See especially his ‘Rules and Subsumption: Mutative Aspects of Logical Processes’, American Philosophical Quarterly, 22, no. 2 (April, 1985), pp. 143-152. Relevant points are also raised in Steven Sverdlik, ‘Counter-examples in Ethics’, Metaphilosophy 16, no. 2 (April, 1985), pp. 130-145. See also Douglas Lackey, ‘Empirical Disconfirmation and Ethical Counterexample’,Journal of Value Inquiry, 10, (1976), pp. 30-34; and J.O. Urmson, ‘A Defense of Intuitionism’, Proceedings of the Aristotelian Society LXXV (1975), pp. 1-12 and 111 -119.

5. Judith Jarvis Thompson, ‘In Defense of Abortion’, Philosophy and Public Affairs, Vol. 1, no. I (Fall, 1971), pp. 47-66.

6. Monroe Beardsley, in Practical Logic (Englewood Cliffs, N,J.: Prentice Hall, 1950) said ‘an analogy doesn’t prove anything’ and regarded analogies as suitable for illustration or hypothesizing but fallacious when used to argue a point. (See p, 107,) R.H. Thouless took a similar view in Straight and Crooked Thinking (London: Pelican Books, 1933), saying ‘any analogy, good, imperfect, or obviously absurd, tends to produce conviction in the same immediate and unreasonable way as does repeated affirmation of a good slogan,’ Susan Stebbing’s position in Thinking to Some Purpose, (London: Pelican Books, 1938), is much the same.

7. William H. Shaw and L. R. Ashley, ‘Analogy and Inference’, Dialogue, Vol. XXII, No. 3. (September, 1983), pp. 415-432. Quoted passage is from, p, 425.

8. Bambrough, Moral Scepticism and Moral Knowledge, and R.W. Newell, The Concept of Philosophy (London: Routledge and Kegan Paul, 1967).

9. S. F. Barker, The Elements of Logic, (New York: McGraw-Hill, 1965). See especially p. 21 and pp. 286-290.

10. John Wisdom, ‘Explanation and Proof’.

11. J. Bickenbach, ‘The Nature and Scope of Reflective Reasoning’, p, 75. Compare Barker, The Elements of Logic, Chapters 6 and 7 and my own A Practical Study of Argument (Belmont. Calif: Wadsworth, 1985 and 1987). Chapters 9 and 10. See also Ashley and Shaw, ‘Analogy and Inference’. These authors recognize the appeal to consistency in moral and logical reasoning as distinct from the empirical basis of many other analogies. However, in my view, the conditions they offer for judging the strength of analogies are not sufficiently sensitive to this distinction. See p. 421. David Hitchcock, in Critical Thinking: A Guide to Evaluating Information (Methuen: Toronto, 1983), cites as a condition for the proper addition of a premise that it does not make any explicit premise redundant. See pp, 76-77, The deductivist or ‘covering statement’ model of analogy violates this very reasonable condition.

12. Classic sources with regard to reflective equilibrium are Nelson Goodman’s Fact Fiction and Forecast (Third Edition) (Indianapolis: Hackett, 1979), pp. 66-68 and John Rawls, A Theory of Justice (Cambridge, Mass,: Harvard University Press, 1971), p. 20f and 48-51. See also Norman Daniels, ‘On Some Methods of Ethics and Linguistics’, Philosophical Studies 37 (1980), pp, 21-36, and ‘Reflective Equilibrium and Theory Acceptance in Ethics’, Journal of Philosophy LXXVI, no. 5 (May, 1979), pp. 256-282.

13. David Hume, Dialogues on Natural Religion, in The Empiricists, (New York: Anchor Press, 1974).

14. John Wisdom, ‘Moore’s Technique’, p. 424.

15. Wellman’s account of induction differs both from some elements of tradition and from my own account, as noted in my critical notice, cited above.

16. Kurt Baier, The Moral Point of View, (New York: Random House, 1958), p. 39.

17. Michael Scriven, Reasoning (New York: McGraw-Hill, 1976), pp. 78-81 and S.N.Thomas, Practical Reasoning in Natural Language, First Edition (Englewood Cliffs, N.J.: Prentice Hall, 1973), pp. 37-40.

18. Thomas made this technique important pedagogically, adapting it from Beardsley. I offer a version in my text, tightening up some distinctions. Chapter Seven (Second Edition).

19. Challenge and Response, p. 29.

20. Michael Scriven, Reasoning, p. 78.

21. Eric Solomon, ‘The Incest Theme in Wuthering Heights’, Nineteenth Century Fiction, XIV (June, 1959).

22. G.E. Moore, ‘Is Existence a Predicate?’, in Philosophical Papers (London: George Allen and Unwin, 1959), p. 126. I am grateful to Jennifer Dance Flatman for locating this and the two preceding examples.

23. G.E. Moore, Ibid.

24. Challenge and Response, p. 16.

25. The Philosophical Works of Descartes, transl.  by E.S. Haldane and G.R.T. Ross, Vol. II, (Cambridge, Eng.: Cambridge University Press, 1968), p. 38.

26. Ibid., p. 127.

27. Challenge and Response, pp. 73-83.

28. Ibid., p. 74.