Knots, RD Laing’s 1970 book, was a collection of short dialogues illustrating the tangle of projection and misreading that characterises human encounters. The radical psychiatrist made clear the influence of unacknowledged baggage, the conscious or unconscious laying of traps for the other speaker, and helped us see more clearly the pitfalls of even our most routine conversations. In an era like ours, where global relations can contain as much psychodrama as private ones, Laing’s Zen-like exchanges have more than just individual pertinence.

The contrast between Laing’s absurdist, tragicomic sensibility and Steven Pinker’s crisp reasonableness is obvious. But there is more common ground than we might at first think. Pinker illustrates his arguments with piquant little dialogues, some of them worthy of Laing (“You hang up first”. “No, you hang up first.” “Okay.” “She hung up on me!”); this book is as lively an exposition of cognitive science as you are likely to find.

The central theme is simply expressed: all acts of communication occur against a background of intricate, recursive assumptions (I know x; you know that I know x; I know that you know that I know x; you know that I know that you know … ad infinitum). What Pinker calls “common knowledge” is both what makes intelligible exchange possible and what complicates it. Communication is not a neat trading of information packages. It is the product of long histories of assumption and symbol; we need to deploy reason in order to arrive at outcomes that are good for everyone involved, and to resist the seductive but potentially suicidal narratives that promise benefit for ourselves alone.

Pinker discusses the famous “prisoner’s dilemma”, in which two criminals being interrogated separately have to decide whether or not to betray each other in order to minimise their sentences. If both refuse to help the police they get a light sentence. If one implicates the other, he or she may go free, while their partner suffers an even worse fate: an enticing possibility. But if each prisoner gambles on that strategy – betraying their friend – then it fails and they’re both jailed for a long time. What this shows is that finding the least unfavourable outcome for all may require parking individual interests.

As Pinker says, this is a pattern that applies to a very wide range of choices – and precisely because of this, it can be tempting to use it as a universal grid for choosing. It is a model in which there is always an optimal answer, where the choices can be set out diagrammatically to show plainly what is best for everyone. But this works only if both parties have some sort of knowledge of the other – or, to put it more realistically, perhaps, have some sort of trust that the other will respond in an intelligible way. When parties in a conflict stand on the precipice of destruction, this trust transforms into a dangerous gamble that each knows the other well enough to predict they’ll back down (partly, in an absurdly ironic twist, because that’s what they would do in the other’s place). It is why the so-called “madman” strategy in international relations (when a leader behaves in such an unpredictable way that no one could possibly guess how they would respond in a crisis) is so powerful a tool for intimidating others.

All this highlights the centrality of “common knowledge” in making sense of another’s acts and words (Pinker is very good on the role of our ability to read physical indicators of thought and attitude). Common knowledge is at work in a whole range of habits that may seem pretty obscure or arbitrary, but which consolidate the mutual trust intrinsic to social cooperation, from myth and ritual to social convention. And this is also why, to cite Pinker’s neat formulation, “rational argument should be really more like a dance than a war”. It is – or can be – a ritual deployment of allusion, shared expectations and cultural performance in which reasonableness is framed and animated by other factors.

Pinker directs his strongest polemic at those who deliberately seek to suppress or limit common knowledge in order to protect what is thought to be a vulnerable or fragile social consensus. He argues that the problem with “the cancelling instinct” is that it muddles fact and value, and, through defending what is “right” via legal or social silencing, reinforces the dangerous inference that claims about what is true are always veiled bids for power. But he is not a free-speech absolutist, and makes a careful case for “quarantined topics” where we might agree that unrestrained communication is disproportionately harmful – as with, for example, the manifestos of mass shooters. He does not quite spell it out, but he seems to be saying that this “quarantining” must itself be a matter of shared cultural discernment rather than inquisitorial processes (whether in the courts or online).

Overall, then, a lucid, measured discussion of what we need to understand about our communications with each other. Pinker shares with a good many other secular philosophers at the moment a tone of deeply exasperated rationality – a default conviction that there really are ultimately reasonable positions about which sane people cannot sanely disagree, and a despairing acknowledgment that this seems an increasingly unpopular idea. He struggles a bit to give weight to aspects of our moral lives that aren’t always amenable to reason (he is predictably dismissive about religion, for example), yet he does ultimately take this dimension seriously, conceding the legitimacy of social markers of solidarity, without which the mutual trust he is exploring would not survive.

This is not a book for anyone in search of metaphysical analysis of the “linguistic animal” (to use the philosopher Charles Taylor’s term). But it enlightens and provokes; to pick up his own metaphor, it is worth dancing with.

• When Everyone Knows That Everyone Knows … Common Knowledge and the Science of Harmony, Hypocrisy and Outrage by Steven Pinker is published by Allen Lane (£25). To support the Guardian order your copy at guardianbookshop.com. Delivery charges may apply.