If we only had eyes to see

How many other humans are in the same room with you now? Two? Then next to you are two other universes, almost unimaginably different from yours. The exploration of those universes is more difficult and more important than the exploration of distant galaxies.

Though the exploration of other human worlds is hard – and often confounded by the human tendency to lie – it is a good deal easier than the attempt to enter the Umwelten of non-humans, like a catfish, which has taste buds all over its body. (It’s one big tongue.) Or an octopus, which has a brain, but delegates much of its sensation and action to its tentacles. Perhaps its arms live in a world of touch and taste, and the head alone “sees”? Where, then, is the octopus itself? Is that a meaningless question?

“I want to know what it is like for a bat to be a bat”, declared Thomas Nagel. We all want to know what it is like to be something other than ourselves. Our heads are lonely places. We’re queasily unsure whether our conversations with “others” are not, after all, conversations just with ourselves. Isn’t the whole business of literature an inquiry into the accessibility of otherness?

Ed Yong, in this immaculately researched, elegantly written, iconoclastic and compulsively readable survey of animal senses, makes otherness seem tantalizingly out of reach. He left me vertiginously disconcerted, for any serious attempt to imagine the perspective of a non-human leaves in ruins our cherished, self-referential presumptions about the kind of place the universe is. Our own view of the world (and, because of the tyranny of vision over our other senses and our cognition, it is our view) is small. We reach our conclusions about everything based on a tiny and partial selection of the available data. Sometimes our ancient intuitions whisper that we’re being misled by a conservative coalition of senses and cognition. Epiphany or breakdown may follow. Yong sets out some of the zoological evidence that justifies the whispering.

His book can be read in many different ways. Some will find it an entertaining freak show – though we’d be wise to remember that humans, choosing to wallow in sensory poverty, are the real freaks. Yong introduces us to male garter snakes that will mate vigorously with a paper towel soaked in female scent; to decapitated flies that groom themselves if they taste (through their feet) bacteria on their wings; to Japanese yellow swallowtail butterflies whose penises are studded with photoreceptors used to guide the penis into the female; to killer flies whose speed of reaction makes “boxing … look like tai chi”; to cockroaches that eat their own guts and male praying mantises that continue mating with the female eating them; to injured squid that don’t nurse individual wounds because they feel a specific injury as whole-body pain; to pit vipers that detect the warmth of a rodent a meter away; to shore birds that create pressure waves in the sand with their probing beaks and detect the distortion of those waves caused by the presence of a buried worm; to blind Ecuadorian catfish whose skin is covered with actual teeth, with enamel, dentine, and nerves; to sensors on the hairs of spiders’ legs that are deflected by a fraction of the energy in a single photon, and are thus 100 times more sensitive than any visual receptor that exists or ever could exist; to the infrasonic waves emitted by fin whales, which can travel for 13,000 miles, raising the possibility that in the oceans there is but a single community of fin whales, all talking to each other; to dolphin ultrasound, which, if beamed at you, would show the blood pumping through your aorta and the food being squeezed towards your rectum, and is so sensitive that it can distinguish between the density of water, alcohol and glycerine; to bogong moths, which, having hatched, fly more than 600 miles to one of just a few caves in the Australian Snowy Mountains; and to seals, which, having excellent vision above their heads, swim upside down to scan the seabed for fish.

Some will read the book as an argument that senses define the future of species. About 400 million years ago some fish hauled themselves out of the sea. With a bit of tinkering by natural selection, they could see much further in air than in water, and (so the biologist Malcolm MacIver has argued) this change prompted the evolution of planning and strategic thinking. “As their Umwelten expanded”, writes Yong, “so did their minds.” Turned on its head, that observation about Devonian-period fish might be the epitaph for postmodernity.

Other readers will be most intrigued by Yong’s nuanced dissection of the relationship between the senses. Senses we know as distinct might sometimes be fused. Touch and smell might be a single sensation for ants. And in humans, smell and taste might be more distinct than we think. Taste seems to be reflexive: smell isn’t. Odors don’t carry meaning until they are associated with experience. The US Army wanted to develop stink bombs for crowd control, but couldn’t find a smell that was disgusting in all cultures.

And many will find here a damning indictment of our own sensory biases and thus our sensory chauvinism. Vision is central to our understanding of the world, and the distorting picture of the world that it gives is almost wholly unmitigated by the other senses. “I see”, we say, when we mean “I understand”. “Picture of the world”, I write, when I mean “comprehension of the nature of the cosmos”.

Being ruled by one sense isn’t a good thing. It tends to trump common sense. Ants, for example, associate the scent or taste of oleic acid with dead ants. Fair enough. But when EO Wilson put oleic acid onto the bodies of living ants, their siblings dragged them off to the cemetery. The smell of death triumphed over the contradictory evidence of wriggling.

This bias has important consequences. One (because of the intimate connection between vision and cognition) is that it leads us to prefer narrow cognitive understanding over other ways of understanding. Another is that we dismiss other ways of perceiving. We’re such a visual species, observes (there I go again) Yong, that we instinctively equate active eyes with an active intellect — which gives us a license to denigrate both non-visually dominant creatures and our own non-visual senses. What a lot we’re missing. We put on shoes and put down carpets and are woefully insulated from the feeling of the ground to which we all return. Though we can echolocate (as shown by the experience of humans born blind, who can learn to ride bicycles through rush-hour traffic by making clicks like bats and somehow detecting the sound that bounces back), almost none of us uses the ability. We use our excellent noses only at wine tastings. Our fingers can determine which of two types of sandpaper is coarsest when the grains are the size of large molecules, yet we use them mainly for hitting computer keys and stroking screens. What might we be!

Since, by and large, we don’t care about the sensory world, but only about our virtual worlds, the planet is awash with sensory pollution. Birds have to sing louder to be heard over the roar of the cars. Street lamps make insects dance until they drop. As container ships grind through the sea, whales stop singing, crabs stop feeding and cuttlefish change colour. We’re the victims of our own carelessness, of course. More than a third of humans can no longer see the Milky Way – so central to many of the old stories told by humans to make sense of themselves.

“The only true voyage”, wrote Marcel Proust, “would be not to visit strange lands, but to possess other eyes … to see the hunched universes that each of them sees.” Yong’s book tries to give us those eyes—and ears, and noses, and other senses attuned to the electrical and the mechanical, to pain and heat, to echoes and magnetic fields—and so equip us, as far as possible, for that.” true voyage”.

It isn’t Yong’s fault, but I couldn’t get far on that “true voyage”. I’m tragically trapped in my own suffocating, cosy Umwelt. I stayed just where I was, mute with wonder. “Every animal can only tap into a small fraction of reality’s fullness”, writes Yong. “Each is enclosed within its own unique sensory bubble, perceiving but a tiny sliver of an immense world.”

In 2017 the biologist Sonke Johnsen, reflecting on the invigorating way quantum physicists deal with uncertainty, wrote a paper entitled “We Don’t Really Know Anything, Do We? Open Questions in Sensory Biology”. That’s proper, humble, exciting science, doing its best to describe the cosmos that is our home, acknowledging that however sophisticated its efforts, it will always be confounded by the real universe out there, and resisting the temptation to describe instead the much more manageable self-created universe of the old paradigms. And that is the ethos of this extraordinary book. Ed Yong lays bare the thrilling inadequacy of our own epistemologies and makes plain the central truth that the more we know, the deeper the mystery.

Charles Foster‘s books include A Little Brown Sea, Being a Human and Being a Best

The post If we only had eyes to see appeared first on TLS.

Leave a Comment