HSV Lecture 2015 – Dealing with peer disagreement: What to do when smart people disagree

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Dealing with peer disagreement: What to do when smart people disagree

HSV Public Lecture by James Fodor, President, University of Melbourne Secular Society, at Balwyn Library on 26 March 2015

Epistemology is the study of knowledge and justified belief. People who are, more or less, equally intelligent, well informed, rational and honest can be described as ‘epistemic peers’.

On many important issues of science, philosophy, politics and religion, equally knowledgeable people often disagree with one another, and this creates the problem of how do we assess and judge these differing views in order to maximize our chances of finding the most reliable position and, as a corollary, our best chance of avoiding false conclusions. Epistemology is the study of knowledge and justified belief. People who are, more or less, equally intelligent, well informed, rational and honest can be described as ‘epistemic peers’.

Faced with this kind of problem, James proposes adopting an ‘equal weight’ view. He describes this as a compromise between adhering to one’s own view, which he calls the steadfast position, and capitulating to someone else’s position completely, the conciliationist position. In other words, ‘I have no greater reason to believe in my judgement than in yours.’

How do we decide what to believe?

What should we believe and what is the difference between judgement and belief? James differentiates the two concepts by saying, my judgement is my considered assessment of the arguments and evidence, and my belief is what I believe is most likely to be the case. But he adds, we do not need to believe our own judgments and in many cases we should not.

For example, if we take a hypothetical issue, one position would be to argue that some reasonably intelligent person has come to the opinion that X is true, and therefore I should believe that X is true. However, we also know that there is considerable disagreement among experts about X, so the opinion of one expert is a bad reason to believe that X is true.

Alternatively, if I do some thinking and reading about X, I may decide that X is probably true. However, this is not a better reason to believe X is true. Our own judgments are more persuasive, as we understand them easily and they fit our world-view more comfortably. But this does not mean that our judgments are more likely to be accurate. In fact the risk of our being biased in our reasoning or judgement is considerable. (Wikipedia, for example, lists about 150 varieties of cognitive bias, that is, the numerous ways in which the subjective social reality of each individual person affects his or her judgement about the objective world.)

Although it is likely that the combined judgements of epistemic peers will be more reliable than that of one expert alone, in making our own judgement we are, of necessity, limited by our own perspective. Richard Fumerton, Professor of Philosophy at the University of Iowa, who has written extensively about epistemology and metaphysics, describes the egocentric dilemma:

… in the final analysis there is really no alternative to the egocentric perspective. Even when my discoveries about what others believe defeat the justification I had, it is my discoveries which are doing the defeating. I can use the discovery of disagreement to weaken my disagreement only insofar as I trust my reasoning.

James advocates assessing the degree of expert consensus. In the case of climate change, he postulates that 97% of climate scientists actually agree about ‘global warming’. Compare that statistic with the public perception, cited by The Consensus Project, of only 45% of people thinking that there is scientific agreement about the issue. This is a significant disparity and likely to influence whether people support action about the matter or advocate for it, politically.

Key points for managing disagreement

  • Ensure that your dispute is not merely semantic.
  • Try to break the argument down into very specific items of disagreement, identify those that are worth pursuing and push those in depth.
  • Don’t get sidetracked by minor points.
  • Recognise that not everyone is your epistemic peer.
  • Try to understand the other’s position well enough that you would be able to formulate and argue it.
  • Figure out what evidence could determine who is right.
  • Identify underlying assumptions contributing to the disagreement, such as worldview differences.
  • Don’t try to defend your position at all costs; try to work out exactly why you disagree.
  • Remember that ideas don’t need respect, but people do.

So, what is to be done?

  • Look for consensus among experts – we don’t need to understand their arguments, but if they are epistemic peers then this carries significant weight.
  • Where experts disagree, remain agnostic.
  • Engage in meta-reasoning frequently. In other words, consider the way in which we have formed a judgement, as well as those with the opposing case.
  • Don’t style yourself as a world expert.
  • Seek disconfirming evidence and viewpoints.


Listed here are examples of some key issues with significant peer disagreement:

  • God exists
  • objective morality exists
  • a priori knowledge is possible
  • fiscal stimulus is effective
  • the mind is computable
  • aid is effective in combating poverty
  • string theory is correct

Further information:

University of Melbourne Secular Society

The Science of Everything, James Fodor podcast

The Godless Theist James Fodor blog

Report by Jennie Stuart