Article by Catherine Z Elgin This article appears in Issue 59 of The Philosophers’ Magazine. Please support TPM by subscribing.
Disagreement abounds. People disagree about everything from sports and politics to science and child rearing. When disagreements stem from the manifest ignorance, bias, or stupidity of one of the disputants, they are epistemologically benign. That someone who clearly does not know what he is talking about disagrees with you gives you no reason to rethink your position. But some disagreements are more worrisome. Equally intelligent, knowledgeable, thoughtful and open-minded people often disagree. Let us call such parties intellectual equals. Should disagreements among intellectual equals give us pause?
Epistemologists disagree. Conciliatory thinkers such as Hilary Kornblith hold that it should. If Fred recognises George as his intellectual equal, he has no basis for thinking that his opinion is better than George’s (or that George’s is better than his). So when they disagree, conciliationists maintain, both should suspend judgement. Advocates of resoluteness such as Thomas Kelly recommend holding fast. If intellectual equals who disagree are always required to suspend judgement, scepticism looms. Given the range of topics on which we disagree with our intellectual equals, we know very little. Resoluteness is permissible, they maintain, because everyone makes mistakes. It is open to Fred to think that where they disagree, George must be mistaken. He is then within his rights to dismiss George’s opinion. Unfortunately, George can think the same about Fred. Resoluteness fosters dogmatism; we are always entitled to dismiss the opinions of intellectual equals who disagree with us by assuming they have made a mistake. Neither scepticism nor dogmatism is an attractive option. A third alternative is that disagreement among intellectual equals provides some reason to rethink one’s position but does not require revising or repudiating it. In that case, parties could reasonably agree to disagree. The challenge is to make room for this position.
Posing the problem so schematically may be misleading. Different disagreements call for different responses. If George knows that he has scrupulously weighed the evidence and has independent reason to suspect that Fred has not done so, it may be reasonable for him to be resolute in his belief that diets rich in kale cause kidney stones even though Fred disagrees. George’s resoluteness here need not be grounded in a general assumption that people who disagree with him are wrong. Rather, he may think that in this particular case Fred has jumped to a conclusion. Dogmatism emerges if he adopts this stance generally.
As the following cases illustrate, conciliation is sometimes appropriate:
Mathematics: Seven friends go out to dinner and agree to evenly split the check. The total comes to $193.91. Pat and Mike are equally good at mental mathematics. Pat announces that each party should pay $27.53; Mike says each should pay $26.93.
Perception: Pat and Mike have equally good eyesight. Pat says that she sees a rabbit in the field; Mike says that he does not see it.
Isolated, ascertainable fact: Pat says that the Battle of Waterloo took place in 1814; Mike says that it took place in 1815.
Isolated, unascertainable (or not readily ascertainable) fact: Pat says that the blue team won the sack race in 1993; Mike says that the white team won. There are no records, and they have lost contact with the other participants.
These disagreements are readily adjudicable; they rest on a bedrock of agreement about what settles such matters. Pat and Mike agree that the correct answer in the restaurant case is whatever one seventh of $193.91 is; and they agree on how to do the calculation. They agree about how to check whether a particular visual perspective is unreliable. They agree about how to ascertain a matter of historical fact, and about what one should think when the requisite information is not available. Plainly both should suspend judgement until they have done the calculation, moved to a better vantage point, checked the disputed fact by appealing to a reliable source. They should suspend judgement permanently if no such source is available.
Sometimes, however, there is no bedrock of agreement. When paleozoologists disagree about the fate of the woolly mammoth, or baseball fans disagree about the strength of the infield, they are apt also to disagree about exactly how to assess such matters. Typically, these disagreements emerge from systematically interconnected clusters of commitments, not only about the topic but also about how to think about it. Cognitive scientists Ken and Alice disagree about whether flavonoids enhance memory because Ken credits the robust results of longitudinal studies which support the hypothesis, while Alice insists on controlled experiments which have not yet been done. In disagreements among intellectual equals, commitments are likely to overlap. But disputants may assign different weights to factors all consider relevant, diverge over whether particular factors are relevant, consider different methods reliable, or differ over thresholds for acceptability.
Even if contending parties agree about what factors are relevant to settling their dispute, and about the general region within which an acceptable answer must lie, they may condone different trade-offs. Both may agree that science seeks generality and precision, but disagree about how to balance one against the other. Both may agree that empirical results must be statistically significant, but disagree about where the line for statistical significance should be drawn. Both may agree that a political arrangement must counterpoise liberty and equality, but disagree about where the balance lies. Let us call such disagreements (currently) inadjudicable. There is no consensus as to the criterion for an adequate resolution.
Perhaps the remedy is to create common ground. Resolve the underlying disagreements, then move on to the topic at hand. How should this be done? Is there an objective fact as to how good evidence must be before it establishes a conclusion? Is there a fact about how many false positives or false negatives investigators should be willing to tolerate? Suppose a test for anaemia is accurate 93% of the time. Dr Henry considers a positive result to afford sufficient reason to believe that his patient is anaemic. Because Dr Murphy insists on 95% accuracy, she suspends judgement on cases where Dr Henry believes. Both agree about what the test result is and about how accurate the test is. They disagree about whether a 93% success rate is good enough – that is, about where the threshold of acceptability lies. Their disagreement about whether the evidence suffices stems from differences in risk aversiveness. If there is a determinate fact about how risk averse one should be in diagnosing anaemia, at least one of the physicians is wrong. But what might such a fact be? Is there a sharp line between being too cautious and being too cavalier in believing test results? If, within certain limits, any of a range of answers is reasonable, then a factual disagreement can be based on differences over something other than a matter of fact.
Suppose Bill believes that generality is more important than precision, while Ellen believes that precision outweighs generality. Their disagreement about the effects of climate change on a butterfly population might stem from a disagreement about precision and generality. Ellen draws precise conclusions that apply only to Monarch butterflies; Bill draws general conclusions that apply more broadly, but that are accurate to fewer significant figures. So Ellen rejects some of the conclusions Bill draws, considering them unacceptably imprecise. Is there a fact as to the proper balance of precision and scope in scientific theories in general? If not, is there a fact in this particular case? If there is, then either Bill’s enthusiasm for generality is overreaching or Ellen’s fondness for precision is nit-picking. But often things are, as far as we can tell, equally balanced. Different trade-offs between precision and generality yield theories that are on balance equally satisfactory.
Maybe the solution here is the same as the solution to adjudicable disagreements: suspend judgement until the more demanding standard is met or suitably fine-grained criteria are framed. If so, suspension of judgement may be permanent. As we saw in the disagreement about the sack race, sometimes a permanent suspension of judgement is reasonable. But such a strategy can be costly. By suspending judgement parties may deprive themselves of resources that could enable them to eventually resolve their disagreement.
To believe an hypothesis is not only to feel that itis true; it is also to be willing to use the hypothesis as a premise in reasoning and as a basis for action in cognitively serious contexts. To suspend judgement involves being unwilling to reason with it or act on it in such contexts. Each judgement we suspend deprives us of a premise. If the premise is false or its justification is shaky, such deprivation can work to our advantage, preventing us from incorporating unwarranted claims into our corpus of beliefs. But we lose inferential power. In suspending judgement about her share of the restaurant bill, Pat lost information she needed to calculate her contribution to the tip. Because that disagreement was adjudicable, that loss was short-lived. But sometimes the loss is more consequential.
A perforated bone fragment was found in a Neanderthal grave. Palaeontologists disagree about whether it is part of a primitive flute. Given its configuration, if it had been found in the grave of a Palaeolithic Homo Sapiens, it would be considered part of a flute. The disagreement is due to underlying disagreements about the level of Neanderthal neurological development. Some hold that Neanderthals lacked the manual dexterity needed to make and manipulate a flute and the intelligence and imagination to invent one. Others think Neanderthals were more gifted. They challenge their opponents to explain what the bone fragment is, if it is not a flute. Little is known about Neanderthals. The available evidence is sparse and equivocal. Each party to the dispute adduces considerations that are consonant with, but relatively weakly supported by the available, uncontroversial evidence. This is not sloppy reasoning. It is the best that can be done with the resources at hand. If the only issue that divided them was the interpretation of the bone fragment, suspending judgement would be reasonable. But palaeontology is riddled with controversies about the Neanderthals. The extent of their tool-making, the structure of their communities, the level of their cognitive and artistic development are all matters of dispute. If disputants had to restrict themselves to considerations that all knowledgeable parties consider firmly established, they would be left with a few isolated facts, but no way to connect them. The fabric of understanding would be riddled with holes and be too flimsy to hang together. If, on the other hand, each group can provisionally accept a hypothesis that is less than secure, their prospects are brighter. Gradually, by playing off their alternatives against each other, they may weave together a tight body of plausible claims that collectively vindicate or rebut the hypothesis that the bone fragment is a flute. By accepting – even tentatively, and with trepidation – a less than firmly established hypothesis, investigators can pursue their inquiries and, with luck, eventually settle the controversy.
Even if this strategy is reasonable, some might argue that it can be pursued without belief. It is perfectly feasible to treat something as a serious working hypothesis without believing it. So perhaps the best strategy is to be conciliatory about belief, and resolute about working hypotheses. Then both groups of palaeontologists can wholeheartedly and single mindedly pursue their investigations, garnering what evidence they can, systematising it as they think appropriate, and making the strongest case possible for their position. They simply should not believe what they say. If we take this position, however, belief attenuates. It ceases to be tied to cognitively responsible inference and action. Scientists would be entitled to use disputed hypotheses as a basis for reasoning and action in their investigations, to argue from those hypotheses, to act on the basis of them. They would be entitled to treat them in their scientific practice just as they would treat hypotheses they believed. If such entitlements are retained in circumstances where epistemologists say that belief is unwarranted, we should probably say, “So much the worse for belief”. This sort of suspension of judgement would have no effect on cognitively responsible practice.
It differs from the suspension of judgement that occurs in adjudicatable cases. There, when parties suspend judgement, they do not and ought not take themselves to be entitled to use the disputed claims as a basis for cognitively serious reasoning or cognitively responsible action. In the restaurant case, Mike does not think he is entitled to put $26.93 (plus a tip) on the table and walk out. Until they do the calculation and resolve the disagreement, he is in no position to say what he owes, hence in no position to pay what he owes.
In inadjudicable cases, intellectual equals disagree, not only about a question of fact, but also about how their disagreement ought to be resolved. Although they largely agree about what sorts of factors are relevant, opinions may diverge at the periphery – one party holding a factor to have a bearing on the issue, the other thinking not. They may disagree about how relevant factors ought to be weighed and/or what the threshold for acceptability is. Still, within roughly specified limits, a variety of positions seem equally acceptable. In such circumstances, rather than insisting that those who disagree with you must be mistaken or consigning yourself and your colleagues to what may be ineradicable ignorance, the best strategy might be to respectfully agree to disagree. Agreeing to disagree entitles each party to draw cognitively serious inferences and engage in cognitively serious actions on the basis of the hypothesis that she favours. Respectfulness lies in acknowledging that on the available evidence the positions taken by one’s intellectual equals are not unreasonable. This is not a position of mindless tolerance of any opinion whatsoever. On the available evidence, palaeontologists can see the merits of both sides of the debate about whether the bone fragment is part of a primitive flute. But they join forces in resolutely rejecting the suggestion that it is a fully functional slide trombone. To be responsible in such a situation, each party must remain attuned to the state of play in the field, recognising that insights that emerge may tilt the balance toward or against her opinion.
I have focused on scientific disagreements, but my points extend to disagreements in all fields. Knowledgeable sports fans may disagree about whether the Steelers are a better football team than the Patriots, because they disagree about the relative importance of a strong running game and a strong passing game. Both are desirable, and a single team is unlikely to be optimal at both. But, arguably, the verdict as to which team is better hangs on where one stands on the question. Here too, respectfully agreeing to disagree seems reasonable.
Earlier I mentioned that epistemologists disagree about whether we should be resolute or conciliatory. What should we make of this disagreement? (I assume that the parties to this dispute are intellectual equals.) Advocates of resoluteness hold that conciliationists ought to be resolutely conciliationist: that is, conciliationists should insist on suspending judgement about which position is correct. But according to conciliationism, given that the resolute disagree with them, conciliationists should suspend judgement about whether we should suspend judgement on the matter. They are, they believe, in no position to insist. The mere existence of conciliationism creates a predicament: only those who do not hold it can, by their own lights, advocate that anyone hold it. If it is reasonable for epistemologists to agree to disagree, they can evade this dilemma. Those who favour resoluteness are within their rights to stand fast in the face of disagreement, while the conciliatory take disagreement as a reason to suspend judgement. Eventually perhaps a resolution will be reached. Perhaps not. But arguably the best way to understand the nature and epistemological significance of disagreement is to endorse a division of cognitive labour, where the members of the epistemological community take the positions they consider most plausible with the utmost seriousness and pursue them to see whether in the end they prove tenable. Consensus may be overrated.
Catherine Z Elgin is professor of the philosophy of education at the Harvard Graduate School of Education. She is the author of Considered Judgement (Princeton University Press, 1996) and Between the Absolute and the Arbitrary (Cornell University Press, 1997).