Talk about the weather

Continuing our "What makes us human?" series.

Shelter from the storm. Photograph: Getty Images

I think it is quite obvious that language is what sets us apart from all other animals. But what is less often recognised is how language enables all the other distinctly human phenomena, transforming inherited “animal” dispositions, instincts, desires and tastes into forms that bear scant resemblance to their ancestral forms.

Humour, for instance, does not exist in other species, though something like laughter, and varieties of playfulness, make their appearance. Religion, similarly, depends on the way language permits us to dwell on puzzles and fears that other animals may experience, but cannot obsess over. We are Homo ludens, the game-playing primate; our games and sports depend on language. So, more obviously, do law and order, science, technology, art and philosophy.

Words inhabit our brains, transforming them into innovative, responsive, adaptable organs – minds – much as “apps” transform our laptops and smartphones. Chimpanzees may be, as Nicholas Humphrey has put it, natural psychologists, but they never get to compare notes, dispute each other’s attributions, speculate on motives, recount and analyse dreams, plan elaborate ruses and stratagems, make promises, tell lies, flatter, insult, console.

So utterly does language transform our minds that it is almost impossible to launder its influence from our imagination when we think of the “minds” of other species. I have called this the Beatrix Potter syndrome, thinking of our animal friends as little people dressed up in fur coats, musing to themselves, chastising each other, informing and instructing and carrying on like human beings, whether or not they wear darling little suits and dresses and live in cute little houses. Disney nature documentaries often commit the same misdirection. Of course, that tradition of (mis-)imagination goes back to Aesop’s fables and beyond, and to a certain degree, it is accurate. Nothing is more natural or useful than treating the animal that we are trying to trap or hunt – or escape from – as an agent with an agenda rather like ours, a wily and cautious self-protector, with goals and plenty of apposite knowledge to guide its pursuit of them. But when we go on to imagine the animal reasoning it out when confronted with a novel situation, we are probably being too charitable by half.

The experimental literature on animal intelligence is full of rather surprising and disappointing failures of animals to tumble to opportunities that, we think, are quite obvious. For every breathtaking feat by an octopus or a New Caledonian crow or a chimpanzee or dolphin, there are dozens of ignominious dunderheads which, after hundreds of trials, fail to see some simple task for what it is. How can animals be so smart about some things and so oblivious to others? We have to take seriously the hypothesis that they aren’t really thinking, the way even human toddlers can think (on occasion); they are perceiving and reacting adroitly, doing “the right thing” without understanding why.

We are the only species whose members try to figure out why to do things, why we have done things, and why others are doing what they are doing. We represent reasons to each other, thereby influencing each other’s behaviour. Being movable by reasons in this way makes us fitting carriers of the burden of moral responsibility. No other species can commit murder, though many kill each other. And if we now see that it is appropriate to hold ourselves responsible for the well-being of other species, we also recognise that this sets us apart from them. They may be suitable bearers of moral value, but we don’t hold them responsible for maintaining, let alone improving, the well-being of others, even of their own species. We may be dismayed or disgusted to learn that lions are likely to kill the cubs of a female with which they want to mate, and we may even feel duty-bound to try to prevent lions (in zoos, for instance) from engaging in this behaviour, but we don’t condemn them for the lion crime of infanticide. They’re just lions, doing what is in their nature. We are not like that.

Talleyrand said that language was invented so that people could conceal their thoughts from each other, a wise – not merely cynical – observation. It is the capacity of language to express our innermost thoughts and secrets that gives rise to myriad opportunities to keep mum, strategically, and to dissemble, strategically, and these opportunities furnish a productive arms race of all-too-human interactions. We are seldom wise to blurt out everything that’s on our minds, and the decisions we make about what to communicate and what to keep to ourselves are major turning points in our lives. Every playwright knows how to tantalise the audience with these forgone opportunities. “Just tell him you love him!”; “Let her know that you know her secret!” we want to call out from our seats, but we know better than to let the words on our lips find voice. Talking, and not talking, is what makes us human.

Daniel Dennett’s book “Intuition Pumps and Other Tools for Thinking” is newly published by Allen Lane (£20) This article is the fifth in our “What Makes Us Human?” series