Ad hominem arguments are generally dismissed on the grounds that they are not attempts to engage in rational discourse, but are rather aimed at undermining argument by diverting attention from claims made to assessments of character of persons making claims. This is evident enough in standard texts on logic and argumentation that caution the use of the ad hominem as subterfuge, appropriate or useful in rhetoric perhaps but not in serious debate or philosophical conversation.Footnote ¹ The claim that is made is that ad hominem criticisms are irrelevant to consideration of the rational persuasive force of arguments, and so should play no role in their evaluation.

The general manner in which ad hominem arguments are dismissed however is based upon an unlikely paradigm of rationality. It is based upon the presumption that our intellectual capacities are not as limited as in fact they are, and do not vary as much as they do between rational people. When we understand rationality in terms of intellectual virtues, however, which recognize these limitations and provide for the complexity of our thinking, ad hominem arguments should be understood differently. For given our intellectual limitations and the pressures we are faced with to make decisions in the absence of final or compelling evidence, it can sometimes be appropriate to appeal to character as a means of settling contention. What this suggests is a much enlarged scope in which ad hominem considerations can be relevant to assessing arguments.

This paper explores this scope, and suggests that intellectual virtues, moral virtues and non-moral character traits can all be legitimate factors in deciding contentious issues that are otherwise irresolvable. When there is a dearth of information or capacity to make decisions, we can rely on these virtues and traits to help choose between courses of action to the extent that they compose coherent character portraits of the individuals who make arguments as to which course we should follow. This is most easily seen with intellectual virtues, but as moral virtues and non-moral character traits suggest intellectual virtues, and as all three mutually support, they all become considerable. There are however no fast rules by which to decide how virtues and traits compose a character portrait, nor to what extent a character portrait is coherent and dependable. Rather, knowing how and when to judge that an appeal to the ad hominem is useful and justifiable is itself an intellectual virtue that must be developed to accommodate our limited capacities.

The modern understanding of the ad hominem considers it generally to have two forms, the circumstantial and the abusive, each of which it considers fallacious.Footnote ² The circumstantial ad hominem (tu quoque) is committed when ‘an inconsistency exists between a statement and the circumstances of its utterance’.Footnote ³ Usually this is understood as when the principles a person advocates in argument are alleged inconsistent with actions they have committed in the past – a ‘practice what you preach’ objection. Such an attack is supposed to undermine the person's argument by accusing them of insincerity, hypocrisy, thoughtlessness, foolishness, etc. It is generally considered fallacious however since a person's personal conduct is claimed to have no bearing on the truth-value of the arguments she makes – a doctor being obese after all does not undermine her advice that you ought to lose weight, nor is a parent's advice to her child that she ought not to smoke undermined by the fact that she herself is addicted.

The abusive ad hominem on the other hand is different from the circumstantial in that it involves a direct attack on the arguer's character. It engages in personal attack based on slander, innuendo, rumour, etc., and is meant to call into question a person's credibility by alleging deviances or shortcomings in that person's authoritativeness or expertise.Footnote ⁴ Examples would be such things as claiming that because someone is a communist their musical taste is suspect; dismissing a person's views on municipal politics because they owe debt; or rejecting someone's argument against a tax increase because they are atheistic. Such attacks are considered fallacious because what is attacked of the person in no way bears on the argument or position they hold – the attack focuses on information or facts about a person irrelevant to the claims that they make. It is an attempt to divert attention to the character of the person who makes the claims, so as to avoid actually having to respond to their claims.

A fair amount of literature has been written on the circumstantial ad hominem, but the form I am interested in considering in this paper is the abusive ad hominem, in particular because it is the form generally considered least salvageable of the two modern forms. I think however that through a virtue epistemology we can justify certain ‘abusive’ ad hominem attacks as being a reasonable form of critique of a person's arguments in situations where we are unable, for whatever reason, to engage in full consideration of the claims they are making.

Interestingly, the abusive ad hominem is not always considered fallacious and indeed is sometimes encouraged, but only in very specific circumstances and even then with strict limitations. The main arena in which it is considered permissible is the legal, as when testimony given by a witness may be questioned by drawing attention to the witness' character. Such criticism of someone's character is not taken to defeat the claims they make, but it is taken as a legitimate questioning of their credibility. Importantly, this version of the ad hominem most generally takes the form of questioning a person's truthfulness, or more generally their moral character. If a person has been shown to be morally unreliable in the past – say they have been known to tell falsehoods, or have been involved in past crimes – then this is considered legitimate evidence to present to a court of law.Footnote ⁵

The legal arena aside, the abusive ad hominem is otherwise generally dismissed on the grounds that are mentioned above: it is considered irrelevant to the truth-value of claims that are made. All this is on the presumption however of a model of rationality that fails to account for our limited intellectual capacities. It is dismissed on the basis of an approach to assessing arguments that fails to appreciate that we must sometimes make judgments without the full and complete evidence that is required for optimal decision-making. When these optimal conditions do not obtain though, as when we do not have the necessary time or facility to fully determine the correctness of claims, ad hominem considerations can play a relevant role. In such situations they cease to be abusive and become appropriate means of evaluation.

Lawrence Hinman is one of the few philosophers who recognize the need for an expanded acceptance of the ad hominem in argument. In his paper ‘The Case for Ad Hominem Arguments’ he suggests three different cases in which the ad hominem can be considered legitimately relevant to consideration of arguments.

The first of these are those situations in which ‘one has insufficient independent evidence about the truth or falsity of the premises of an argument.’Footnote ⁶ In situations such as this Hinman's concern is with an arguer purposefully misleading his interlocutors, or unintentionally misleading others as well as himself in confusing how he wants things to be with the way things really are. When this is the case and one is unable to confirm the arguer's premises, it can be appropriate Hinman says to resort to character evaluation in order to decide whether the person is reliable and whether or not to accept their arguments.

The second case in which the ad hominem can be appropriate are those situations in which ‘in dealing with inductive arguments, there is…room for legitimate dispute about how strong the evidence should be to justify accepting the conclusion.’Footnote ⁷ The difficulty in such situations is that different people may hold different standards as to what constitutes sufficient evidence for dependable or reliable inferences. The probability threshold that must be met to make inferences that is may be held higher or lower by different people. In such situations, Hinman says, it can be appropriate ‘to raise questions about one's opponent's background and motives insofar as such questions are focused on the issue of whether the person's background and motives have led to setting the demand for certainty too high or too low’.Footnote ⁸

The last case in which the ad hominem can be relevant concerns those arguments that proceed from within particular philosophical traditions such as Marxism, contemporary sociology of knowledge, or existentialism, and from the presumptions of people operating within these traditions that the truth and falsity of ideas is dependent upon the ideological commitments of the people who advance them. For example, the claim is that Marxists will criticize arguments made by capitalists on the grounds that their capitalist inclinations will colour their worldview and influence all their arguments and judgments. Rejecting capitalists' arguments on the grounds they are made by capitalists is thus considered a legitimate form of criticism within the Marxist paradigm. More broadly speaking, the claim is that the ad hominem is a legitimate form of critique since genetic reasoning is accepted by these traditions and there are no such things as non-value-infused claims.

In each of these cases the claim Hinman makes is that ‘what would appear to be an instance of the contemporary version of the ad hominem fallacy seems to be accepted as a sound philosophical principle’.Footnote ⁹ He suggests that sometimes when these three cases occur they indeed are fallacious, but also that this is not always so, and so considering agents' reliability, motives, and ideological traditions can all be relevant to evaluating arguments.

Now one objection that can be made to Hinman is that his claims regarding the acceptability of the ad hominem may be conceded when dealing with values, but are not admissible in areas in which stronger claims to truth can be established, such as in the sciences. Hinman however anticipates this objection and responds by asserting the underdetermination of theories by facts, suggesting that there is a ‘slack’ in our beliefs which may be taken up by non-factual considerations. In such cases, he claims, an ad hominem argument may be relevant ‘insofar as it calls attention to the way in which the individual's background or motivation has played a significant role in taking up this slack’.Footnote ¹⁰ The claim in other words is that if there is an irreducible human element to our scientific claims, then even our scientific knowledge claims are determined in part by us as well as the world, and so ad hominem considerations can become relevant to our beliefs and judgments of arguments.

In response to Hinman's arguments, Gary Jason takes a position that is typical of the philosophical tradition with regards to the legitimacy of the modern ad hominem. Considering each of Hinman's cases, Jason claims that in no situation is the ad hominem justified, and that what is needed instead is further thought and investigation.

Regarding Hinman's first claim that appealing to character can be justified in times of insufficient independent evidence about the premises of someone's argument, Jason responds by saying that character evaluation cannot be resorted to and only further investigation in such situations is appropriate. If one is unsure about the validity of the premises of someone's argument, then the only thing to do is to examine those premises oneself.

Regarding Hinman's second claim that there can be disputes about degrees of certainty in accepting inductive arguments, and that in such cases it can be legitimate to raise questions about someone's background in deciding whether they have set an appropriate standard of certainty, Jason's response is similarly that the only recourse is not to consider the person's character or background at all, but to ‘look into the topic’ and decide for oneself what degree of certainty is enough.Footnote ¹¹

Lastly, regarding Hinman's third claim that Marxists, sociologists of knowledge and existentialists often accept ad hominem (or more specifically genetic) reasoning, Jason's response is not that this is justified in any way, but that this merely indicates poor reasoning. That people reason by invoking the ad hominem is no justification of such reasoning, for such reasoning should be dismissed as faulty.

It seems clear here though that we can defend Hinman's cases on the basis of an appeal to epistemic virtues. Taking as a starting point the idea that we have limited rational capacities, there will be times when we just cannot do what Jason suggests we do in always engaging in further investigation or looking into the topic ourselves. We may either not have sufficient time to do this – or even if we do we might not be prepared to dedicate that time given other demands we face – or we may not have the necessary intellectual skills or abilities to understand the issues concerned. It may well be in such cases that the reply is made that judgment should thus be suspended; but often decisions are required of us even when we are unable to determine the issue fully factually to our satisfaction. In such cases it seems we have to appeal to criteria other than the facts of the case since those facts are underdetermining. Turning at this point to judging the people who consider the facts can now be a sensible progression.Footnote ¹²

As an example, consider being presented with two arguments about an issue by two scientists. You yourself are not a scientist, and are only superficially familiar with the issue at hand. Suppose that you are in a position of authority and have to make a decision between the two arguments that will affect policy of some kind. Each argument seems as coherent as the other, and each scientist has impressive credentials and the respect of others in the field. Further investigation may reveal more evidence, but it is unlikely that this new evidence will make either side any more compelling. In making a decision, it seems fair at this point to appeal to relevant features of the character of each person making an argument. Suppose that the one scientist is generally very conservative in his approach and gives great credence to his tradition, believing that best solutions are found by gradually amending previous work. The other scientist is more creative and radical in her thinking, believing that since previously suggested solutions have not worked, a conservative approach will just as likely fail and that what is needed instead is a shift in thinking – this is what she suggests. It seems plausible at this point to decide for and against arguments based upon the general approach that each person takes – as determined by their intellectual virtues – since the facts of the case themselves are not conclusive.

Or, suppose that you are involved in determining public policy and are presented with proposals by two analysts. Suppose that both analysts have examined the same data, but that the one analyst is known to be more charitable in her interpretation of data than the other – that is, when confronted with inexact or somewhat vague data (say written opinion polls) she is more likely to interpret the data as what she believes it implies rather than what it distinctly states. The other analyst on the other hand refuses to consider vague data of this sort, discounting it instead as contaminated. What we have here is a methodological difference in analysis given the one person's greater concern with precision and the other's belief that precision is not always possible and that interpretation of results is sometimes necessary. The suggestion then would be that there is no real truth to the matter as to which analyst is right or wrong, but that the matter is decided based upon what sort of methodology one thinks is most appropriate. Supposing one is more concerned with exact results for a smaller sample than less exact results for a broader sample, then one would decide between the analysts' proposals not so much by how the proposals reflect the facts of the matter, but by how the analysts each approach the facts given their exercise of different intellectual virtues.

As a third example, consider two opposing arguments put to you, both of which seem compelling, but neither particularly more so than the other. You are then told who developed each proposal. It turns out that the one person has a reputation for great foresight or perceptiveness or perspicacity in her work, whereas the other person has no such reputation, even though their work is generally respected as efficient and dependable. In this case, one may well decide between the arguments based upon the past achievements of the persons concerned, even though there seems nothing much to choose between the arguments themselves. This would then be a clear case of employing ad hominem considerations in deciding the issue.

We can see further cases for defending the ad hominem by changing the emphasis to intellectual vices. Suppose again that two different arguments are put to you by two different people, and you have to make a decision between them. Both arguments seem compelling, but it is known that the one person is somewhat dogmatic about certain claims obliquely relevant to the issue, whereas the other person has no such investment and is generally open-minded to all sorts of different accounts. Again, there may not be much to tell between the arguments themselves – the facts can be interpreted to support both arguments – but we may well decide the issue based upon facts about the people and their intellectual character rather than what it is they actually say.

The point in each of these examples is that Jason's response to Hinman (and thus the response typical of the tradition) will not work. Going back to examine the evidence or spending more time looking into the topic, within the limits practically available to one, will not in these examples reveal any greater reason to accept the one argument over the other. What it more likely comes down to is deciding the issue based upon other criteria, such as methodological approach, willingness to consider evidence, extent to which one is willing to accept vague evidence, creativity of thought, perceptiveness, foresight of thought, and so on. And the important point is that these various virtues which may well be considerable need not be directly evident in the arguments in question. It could well be that the argument of someone known to have a general propensity to think in a certain way might be thought better than the argument of someone who does not think that way, even though both arguments seem equally compelling, and the different virtues which make their character are not immediately evident in the arguments made. In such cases we invoke the ad hominem and seem justified in doing so.

Knowing the intellectual character of people who put forth arguments can thus have bearing on how we consider their claims. There is more to arguments than the words that are used, especially when one is unable to verify their premises. This is easily enough seen when we compare an argument as put forth by a child and the same argument as put forth by an adult. There is credibility to the adult not borne by the child and this is enough to make us suspicious of what the child says. Similarly, different intellectual approaches to argument can suggest greater or lesser credibility, depending in many ways upon our own predilections. It is questionable how far this can go, however: to what extent can character assessment be relevant to considering arguments? Can moral character for instance have bearing on how we evaluate arguments? This is usually outright dismissed as fallacious, but if intellectual virtues can rightfully be considerable, if moral virtues can be suggestive of intellectual virtues can they be rightly considerable too?

As a simple example we can consider two arguments regarding some social issue. Each argument seems compelling, but it is known that the one person has feminist inclinations and is concerned about marginalization. Presuming either no time to recheck the data, or that the data is amenable to all sorts of different interpretation, in such cases one might decide between the arguments on the basis that the feminist is likely to have interpreted the data in a more charitable way than the nonfeminist. This charity of interpretation may not be directly evident in the data-analysis provided, but given knowledge of the person's general character and sympathies there may well be reason to support the feminist's proposal over the nonfeminist's. The decision is not being made so much on the basis of the argument itself as presented, as on the basis of how the moral character of each person respectively affects their arguments.

This example suggests a reasonably close connection between an agent's moral inclinations and her intellectual projects. How about though if this connection is made more tenuous? A number of examples can be offered in which moral virtues and vices can be thought but suggestive of intellectual virtues and vices:

1. 1. If somebody is morally empathetic they may be thought also to be intellectually empathetic. So somebody who demonstrates great moral consideration for the various ways in which their actions affect others (an ideal utilitarian for instance) might well be thought to also have the capacity (and inclination too) to consider a variety of different intellectual viewpoints in making their intellectual arguments. Another person on the other hand who fails to demonstrate this moral capacity might be suspected as to whether they would demonstrate the intellectual capacity.

2. 2. If somebody demonstrates moral humility they may also be thought to exercise intellectual fair-mindedness. A belief that one is not better or more important morally than others, and a demonstration of this in one's everyday living, might well suggest a willingness intellectually to treat all viewpoints alike without reference to one's own feelings or vested interests. It might suggest in other words an adherence to intellectual standards without reference to one's own advantage or the advantage of one's group. Moral humility might also suggest intellectual humility, in that belief in one's moral non-superiority might indicate modesty in one's intellectual claims and an unwillingness to claim more than one actually knows.

3. 3. If somebody has shown themselves to be morally corrupt, seeking to take advantage of others for their own benefit, then they may be thought to be intellectually corrupt in arguments since their fidelity may be suspected to be not to the determination of truth but to self-advancement and personal benefit.Footnote ¹³

4. 4. If somebody demonstrates moral courage they might also be thought to be intellectually courageous. If moral courage is understood as courage in following one's ethics despite the potential alienation this might result in from friends and family, then such a person is likely willing to address ideas or beliefs which are unpopular or dangerous and so display intellectual courage.

None of these connections is causally or logically necessary, in that it could be quite possible to exercise one of the moral virtues without exercising its intellectual counterpart; but in each example it seems a fair case can be made for the correlation of the moral and intellectual virtues. Consequently, in such cases where arguers demonstrate these moral virtues one might have reason to consider their arguments in light of the intellectual virtues with which they are here associated. If the suggestion of an intellectual virtue by the presence of a moral one seems valid, then the argument can be considered in terms of the intellectual virtue suggested. This has to be done with caution however since the correlation is only suggestive and may not in all cases bear scrutiny. That this is so is evident enough in other examples that can be suggested in which we would be less likely to presume as strong a connection between moral and intellectual virtues and vices. For instance,

1. 1. That one demonstrates moral absent-mindedness need not suggest intellectual absent-mindedness. One could be quite forgetful of promises made to friends or of duties to family, but be quite conscientious in one's intellectual projects. The archetype for this would be the absent-minded professor (consider for instance the example of Thales who whilst engrossed in thought fell into a well).

2. 2. That one is morally disloyal need not suggest intellectual disloyalty. One might easily betray one's spouse and yet remain loyal to one's intellectual projects and persevere with one's endeavours despite obstacles and temptations to do otherwise.

3. 3. That one is short-tempered and intolerant with one's friends or relations need not suggest intellectual intolerance. One could be extremely open-minded to others in one's professional life and forgiving of mistakes made in the interest of creativity and intellectual progress, but quite intolerant of the idiosyncrasies and foibles of one's family or those not involved in one's intellectual ventures.

The point these examples are meant to demonstrate is how tenuous the connection may be between moral and intellectual virtues. The first set of examples suggests a reasonably plausible connection between the two, but this second set indicates how contingent any relation may be. In each situation it will depend upon the particular circumstances and the particular figures involved as to how much one can rely upon moral characteristics to suggest intellectual traits of character.

To further complicate this scheme of moral virtues that might or might not suggest intellectual virtues, there is also worth considering the connection between intellectual virtues and what I shall call non-moral character traits. The suggestion is that certain interests one has or activities one engages in might, similarly to moral virtues, be suggestive of intellectual virtues, and so potentially be considerable in evaluating inconclusive arguments. Consider for instance the following:

1. 1. An interest in fine wine might suggest a subtlety of distinction that could in turn suggest the intellectual virtue of attention to detail.

2. 2. Experience in world travel might suggest an interest in new ideas and the intellectual virtues of curiosity and open-mindedness.

3. 3. An appreciation of abstract art might suggest the capacity for metaphorical thinking and the intellectual virtues of creativity and imaginativeness.

4. 4. Participation in sport could demonstrate an appreciation of competitiveness and could suggest the intellectual virtues of perseverance and tenacity.

Again, none of these connections is causally or logically necessary, and it could be quite possible to find these traits suggestive of other virtues or vices than those I have suggested. Indeed, many might find the connections here quite fatuous: an interest in fine wine for instance could just as easily suggest pretentiousness; an appreciation of abstract art might suggest elitism; participation in sport might be thought to suggest neither virtue nor vice at all. It is this sort of uncertainty that has led to such doubts about considering such character traits relevant to judging arguments.

But what I would suggest is that whilst this uncertainty about intellectual character is certainly appropriate in considering these traits or moral virtues discretely, should a number of such traits and virtues be considered jointly they may give one greater confidence in making inferences about someone's intellectual character. So for instance, should an individual not just be known to be open to bribes, but to be selfish in their manner of dealing with other people and have parochial interests in general also, we might then have good reason to question their intellectual fair-mindedness and their willingness to consider intellectual claims independently of their own interests. Or, should an individual not only be well-travelled but demonstrate moral empathy and moral humility as well, it might be quite reasonable to judge that in their intellectual projects they are likely to be open to new ideas and not closed-minded or dogmatic. These sorts of evaluations can be especially relevant should these traits be compared to the traits of another which do suggest a closed-mindedness and dogmatism, and whose arguments are in contention with those of the first person.

In all of these cases the suggestion is made that these ad hominem considerations can have bearing on our evaluation of arguments. Ideally they need not and should not be considered, as when decisions are readily made or arguments can be tested by more reliable means (by further investigation, by appeal to expert authority, etc.). But on those occasions when decisions are not readily made and further investigation is not possible or not likely to be fruitful, then appealing to congeries of traits people have (intellectual, moral and non-moral) that may influence the sorts of arguments they produce can be a legitimate method of coming to a decision. No such trait should be considered discretely because of how tenuous the links are between virtues and soundness of arguments (individually after all the links are nothing but suggestive), but considered in aggregate the tenuousness of links can become reliable to the point where an inference can be considered defensible.

My claim as such is that in those situations where arguments are inconclusive, to appeal to the ad hominem should not be thought necessarily fallacious. Some appeals to character traits will obviously be irrelevant (as when one's preference of Mexican to Italian food for instance is used to resolve a dispute about public policy), but others may be considered quite relevant. For instance, one's attention to detail, or one's creativity of thought, or one's foresight and perceptiveness, can all be legitimately considered in evaluating one's arguments even if those virtues are not evidently manifest in what one argues. The virtues themselves should not absolutely determine disputes between arguments, but they can lend enough support to the one or the other (or create doubt if a vice) in order for decisions to be made.

The claim then is that it can be legitimate to consider how intellectual virtues affect arguments in resolving otherwise irresolvable disputes. Furthermore, since moral virtues may be suggestive of intellectual virtues, these too may be considerable in deciding between arguments, and so also non-moral character traits. The difficulty with these moral virtues and non-moral traits though is that they are that much more removed from intellectual virtues which themselves can only insinuate decisions. Appealing to moral virtues and traits is thus that much more tenuous a means to decide arguments and thus that much more susceptible to ad hominem objections.

The response to this is that whereas indeed these concerns are well-founded, the appeal may still be justifiable. We may sometimes not know for instance someone's intellectual virtues although we may know some of their moral virtues. In this case, considering their moral virtues might suggest to us their intellectual virtues. Or, in considering the intellectual virtues of two people to decide between their conflicting arguments, we may find their evident intellectual virtues differently but equally supporting their respective arguments (perhaps one demonstrates great creativity whereas the other demonstrates charity of interpretation); in such a situation it might make sense to appeal to their moral virtues or non-moral traits to help decide the stalemate between their intellectual virtues (by these perhaps suggesting further intellectual virtues, or suggesting a possible depth to their evident intellectual virtuesFootnote ¹⁴) and thus decide the stalemate between their arguments.

In each situation it must be recognized that these ad hominem appeals are only suggestive and should only be invoked expediently. It must also be recognized that since the intellectual virtues are suggestive only, the hesitation we should feel in appealing to them to help decide arguments should be even greater when appealing to moral virtues and non-moral traits, since these are only appealed to as suggestive of intellectual virtues, and are thus twice removed from their bearing on arguments. To appeal then to a moral virtue or non-moral trait alone to decide an argument is deeply suspicious, since that moral virtue or trait could be interpreted as indicative of some other intellectual virtue or vice that could count against the argument it is taken to support – in a case such as this accusation of the ad hominem fallacy seems appropriate. Indeed, appealing to a single intellectual virtue is also suspicious, since it too could be interpreted differently, or other intellectual virtues could be found to support the argument with which it is in contention.

However, these virtues can be responsibly and non-fallaciously appealed to when appealed to in combination with each other. In this case they become mutually supporting as they help compose a portrait of the individual-in-question's character. Intellectual virtues directly evident will be taken to have more weight than intellectual virtues as suggested by moral virtues and non-moral character traits, but all these can be relevant as they contribute to an impression of the person who makes an argument. Generally speaking, the suggestion would be that the stronger or more coherent the character portrait that develops from consideration of these virtues and traits, the more compelling the ad hominem appeal, and the less the objection of ad hominem fallacy, in making a decision between arguments. So for instance, if a person appears to have certain intellectual virtues that incline you more towards their argument than another but you are unsure whether they actually possess those virtues, should they also demonstrate several moral virtues and non-moral character traits that seem supportive of those presumed intellectual virtues, then you can have more confidence in trusting in those virtues. Or, if there is this same uncertainty, but the moral virtues and non-moral character traits on the contrary do not support at all those intellectual virtues but seem suggestive rather of virtues (or vices) much different, then this would give one legitimate reason to be doubtful of those intellectual virtues.

There can be no hard and fast rules as to when moral virtues and non-moral character traits are supportive of intellectual virtues, nor any hard and fast rules as to how intellectual virtues should be considered relevant to arguments. There can also be no simple method by which to determine the strength of a character appraisal that arises from considering these virtues and traits in combination with one another. How these judgments are to be made as such is a matter of circumstance and prudence: different intellectual virtues will be relevant to different ends, and how those intellectual virtues are supported by moral virtues and non-moral traits will depend on the circumstances in which they are exercised (so that if one's travel experience is a matter of personal interest then this might have different bearing than if it is work-related, or if one is short-tempered with one's family because they are particularly annoying then this would have different bearing than if they are generally quite peaceable).

Whether and when these ad hominem appeals are justified will thus also be a matter of judgment: it itself is an intellectual virtue to know when appeal to the ad hominem is useful and justifiable. For some, ad hominem considerations may be justified in circumstances in which for others they are not – perhaps those who object would want further investigation of an individual's virtues and traits. This of course presents problems of its own insofar as such further investigation may not be possible given time and other constraints, at which point decisions again just have to be made on the basis of limited evidence. In such situations we just have to accept that optimal conditions are not available for decision-making, and that any judgment we make will be wanting in some way. As a consequence, in making such judgments there is also always the need for the virtue of vigilance, and of readiness to revisit one's judgments on presentation of further evidence.Footnote ¹⁵