If Nietzsche Were a Narwhal by Justin Gregg review – the problem with human intelligence

Friedrich Nietzsche claimed that humankind was “a fantastic animal that has to fulfil one more condition of existence than any other animal”: we have to know why we exist. Justin Gregg, a researcher into animal behaviour and cognition, agrees, describing humankind as “the why specialists” of the natural world. Our need to know the reasons behind the things we see and feel distinguishes us from other animals, who make effective decisions without ever asking why the world is as it is.

Evidence of this unique aspect of our intelligence first appeared 44,000 years ago in cave paintings of half-human, half-animal figures, supernatural beings that suggest we were asking religious questions: “Why am I here? And why do I have to die?” Twenty-thousand years later, we began planting crops, revealing an awareness of cause and effect – an understanding of how seeds germinate and what to do to keep them alive. Ever since then, our constant questioning of natural phenomena has led to great discoveries, from astronomy to evolution.

But rather than being our crowning glory as a species, is it possible that human intelligence is in fact a liability, the source of our existential angst and increasingly apparent talent for self-destruction? This is the question Gregg sets out to answer in his entertaining and original book.

It is the very complexity of our intelligence that may well make us less successful in evolutionary terms

The delightfully absurd title stems from his claim that the 19th-century German philosopher, who had depression and eventually dementia, was “the quintessential example of how too much profundity can literally break your brain”. The “soul-tortured Nietzsche”, who sought meaning in suffering, is an example of how, as a species, we are simply too smart for our own good. By contrast, the narwhal (“one of my favourite marine animals”) demonstrates the fact that, from an evolutionary perspective, intelligence and complex thought are often a hindrance: “The absurdity of a narwhal experiencing an existential crisis is the key to understanding everything that is wrong about human thinking, and everything that is right about animal thinking.”

In search of evidence to support this theory, Gregg explores the nature of intelligence. Although non-human animals may have simpler minds than us, they are no less successful in their own way than we are, and do far less harm to their fellow beings: “The Earth is bursting with animal species that have hit on solutions for how to live a good life in ways that put the human species to shame.”

Human intelligence is augmented by what Gregg calls our “additional cognitive sprinkles”. These include language, theory of mind, causal inference, our capacity for moral reasoning, episodic foresight (the ability to mentally project ourselves into the future to simulate imagined events) and death wisdom (an awareness of your own mortality). But, he argues, it is the very complexity of our intelligence that may make us less successful in evolutionary terms, destined to vanish from the Earth before other species, such as crocodiles, who are stupider but have been around for millions of years. What is the point of all our intellectual achievements, Gregg asks, if we go extinct after a mere 300,000? If climate change is to be our downfall, then human intelligence may just turn out to be “the stupidest thing that has ever happened”.

Gregg is a brilliant communicator of complex ideas, with a writing style that is rich in both humour and detail. His argument is also surprisingly convincing. He concludes that Nietzsche would indeed have been better off as a narwhal. The less complex minds of non-human animals should not be regarded as inferior, but rather as wonderfully successful solutions to the problem of how to live pleasurably, without threatening the survival of others.

• If Nietzsche Were a Narwhal: What Animal Intelligence Reveals About Human Stupidity by Justin Gregg is published by Hodder & Stoughton (£22). To support the Guardian and Observer, order your copy at Delivery charges may apply