Why must relativists "allow that there is a subculture of rationalists, who believe that the principles of reasoning are universal"?

Question

From: Philip Johnson-Laird BA PhD Psychology (UCL), Stuart Professor of Psychology Emeritus at Princeton. (Author isn't a logician.) How We Reason (1st edn 2008). p. 275.

Do Kpelle rice farmers in Liberia reason in the same way as villagers in remote Uzbekistan? Do Asians reason in the same way as Europeans? Do we reason in the same way as our ancestors? Social scientists argue about these questions. Some say that human beings reason much the same the world over and always have done so; their opponents say that human beings differ in how they reason depending on their culture. Some argue that the norms of rationality should be the same for all cultures; their opponents—so-called “relativists”—argue that norms should differ and depend on the local culture. Hence, what is rational for the Azande of Central Africa is irrational for Evans-Pritchard, the English anthropologist who studied them, and vice versa. It is hard to resolve controversies about norms, but the educability of peoples from all over the world suggests that no profound differences in reasoning exist from one culture to another. The debate has often been couched in terms of formal rules of inference. No formal rules are universal, relativists say. But, their argument presupposes that we use formal rules. From the standpoint of the model theory, the question to pose is: do all cultures realize the force of a counterexample? Show me a culture that does not, and I will concede that relativism is right for some cultures, though not for mine.
  Relativism has an aura of self-refutation (like my last remark), because relativists must allow that there is a subculture of rationalists, who believe that the principles of reasoning are universal. Suppose relativists claim that rationalism is right in its subculture. It follows that the principles of reasoning are universal, because that’s what rationalists believe. And so relativism is wrong. Suppose rationalism is not right in its subculture. It follows that there’s a culture whose principles of reasoning are not right, and so relativism is wrong. Either way, it follows that relativism is wrong.

Why's the emboldened sentence true?

I understand that relativism is self-refuting, but for this different, more straightforward reason:

1. All truth is relative.
2. If all truth is relative, then the statement "All truth is relative" would be absolutely true. If it is absolutely true, then not all things are relative and the statement that "All truth is relative" is false.

Answer 1

Johnson-Laird on relativism

relativists must allow that there is a subculture of rationalists, who believe that the principles of reasoning are universal. Suppose relativists claim that rationalism is right in its subculture. It follows that the principles of reasoning are universal, because that’s what rationalists believe. And so relativism is wrong. Suppose rationalism is not right in its subculture. It follows that there’s a culture whose principles of reasoning are not right, and so relativism is wrong. Either way, it follows that relativism is wrong.

It is not encouraging that Johnson-Laird does not enumerate and specify types of relativism. But I guess he has cognitive relativism in mind.

Spelling out what cognitive relativism entails

Steven Lukes is helpful here :

By cognitive relativism I do not mean the empirical thesis that there is a diversity of world-views, theories, forms of explanation, modes of classification and individuation, etc., but rather the philosophical thesis that truth and logic are always relative to particular systems of thought or language: on this view, what is true and how successfully to ascertain it, and what is a valid or consistent argument are always internal to a system, which is itself one among others and relative to a particular social group or context or historical period. (Steven Lukes and W. G. Runciman, 'Relativism: Cognitive and Moral', Proceedings of the Aristotelian Society, Supplementary Volumes, Vol. 48 (1974), pp. 165-189+191-208 : 168.) [Note : Lukes does not accept cognitive relativism.]

Back to Johnson-Laird

Suppose relativists claim that rationalism is right in its subculture. It follows that the principles of reasoning are universal, because that’s what rationalists believe. And so relativism is wrong.

Nothing of the sort follows. What does follow is that 'truth' is relative-truth - truth internal to a system. Truth-internal-to-system X is that the principles of reasoning are universal. It is not the case that therefore 'the principles of reasoning are universal' just because it is true-internal-to-system X that the principles of reasoning are universal.

In any case, Johnson-Laird uses a non-relative notion of truth when he says, 'it follows that relativism is wrong'. The cognitive relativist can turn the tables and claim that 'it follows that relativism is wrong' it itself relative-truth - truth internal to a system - Johnson-Laird's system, the system of the cognitive community to which Johnson-Laird belongs.

A cognitivist relativist might apply the same considerations to my critique of Johnson-Laird. But that doesn't help Johnson-Laird at the point where he stops the argument.

Answer 2

It seems to me the 'subculture' Johnson-Laird is talking about, is the one which wishes to communicate discuss and compare with other subcultures.

A universalising notion of truth can be related to power, like Foucault. Especially in times of rapid technological change, ideas that result in people being able to for whatever reason dominate the narrative, become 'true'. If Nazi Germany had won, we might have a much more Newspeak undersranding of truth.

'Rationalists' may wish to believe a subset of people are drawn to create a wider discourse, to analyse and compare and understand. This has been a very succesful cultural mode, including at spreading & reinventing itself. But it is a choice, albeit one consistently rewarded by technological breakthroughs, and more arguably social positives like better international cooperation - and perhaps social dangers like unconcern about the dangers or unproven safety of technologies.

When we look at how actual societies have thought, especially uncontacted tribes or cultures seperated from global culture, we find there is huge variety including dominant 'irrationalities'. Of course there are discourses around power, capacities, and values, in all microcosm societies too. His assertion doesn't stand up to observations.

Humans use 'reason' like deer use antlers, and we call the ones that win most the most rational.