t was a near-perfect day on the south coast – blue sky, blue sea, enough breeze to offset the heat of the sun. The beach may have been a little full, but it wasn’t long before I was in the water. I’m an OK swimmer and struck out easily for a couple of hundred yards. With an offshore breeze, there wasn’t much in the way of waves. It was lovely being away from people, at ease in the undemanding, light-shot sea, my body moving in the slight surge of an old swell. Then I turned to head back in. And the mood changed. With the wind behind me the waves had felt trivial, but now, further out, they were lifted by the breeze. Small they may have been, but they were steep-sided, each with its own little kick. One after the other they hit me in the face. I didn’t have goggles on, my eyes were stinging and I was having trouble seeing where I was going. Every so often I took a mouthful of water. I didn’t seem to be getting anywhere – what I could see of the shore remained stubbornly out of reach. I started to fight panic, as well as the waves. During lockdown we have been enjoined to connect – or reconnect – with nature. For the sake of our mental health, we are urged to leave behind a world mediated by screens, get out into the green stuff, breathe some air, see some horizons. Wonderful advice it is too, and I have heeded it. In successive lockdowns I discovered the unlikely charms of the river Wandle, twisting its way from its source in Croydon, through the burbs and light industry of south London before discharging into the mud of the Thames. Likewise, Mitcham Common – several hundred neglected acres of slightly feral, down-at-heel scrub butting up against the Wandle. But for all the exhortations about connecting with nature, there is a paradox. We are in the middle of the single biggest global upheaval since the second world war. Its purpose: precisely to disconnect us from nature, or from that tiny fragment of it known as Sars-CoV-2. The nature we are invited to connect with is ordinarily a small, picturesque and highly managed subset of the wild world. In the UK, the chances are it resembles parkland or farm country. These are places where any threat to us has largely been removed. There will be footpaths to facilitate access, neighbouring car parks, proximate pubs and cafes. Along with reconnection, this is the nature we ordinarily have in mind when we consider conservation: defending our green spaces from various forms of defilement. Lovely as much of it is, this is nature as amenity, somewhere deliberately set back where we can wander and breathe, get a little respite from the heckle and commotion. However rewilded, it remains under human sovereignty: it is effectively nature as garden. When I finally made it back to shore on that lovely summer’s day, shaken, relieved, slightly embarrassed, it was after having tussled with another kind of nature. This is nature as blind and indifferent process, that sum of forces, animate and inanimate, at work in the physical world. This version of nature is operative within and without us. This is the nature we encounter in earthquakes and landslides, but also in cancer, the anopheles mosquito and Sars-CoV-2. It is also the nature that Darwin famously recoiled from in parasitic wasps, those gracile insects that paralyse their hosts before laying eggs inside them to ensure living meat for their emergent young – precisely the nature that shook his belief in a “beneficent and omnipotent God”. In Ash Before Oak, Jeremy Cooper’s slow and subtle account of a “nature cure” in the Quantock Hills, the narrator describes how a sheep farmer friend found “on her morning round of inspection a ewe on its back, alive, its blooded udder eaten by a fox, the lamb standing at its mother’s side bleating”. The nature that cures can also shock and horrify. “Nature” is among the trickiest words in the language. A single noun to cover quantum mechanics, tsunamis, the Ebola virus and bluebells will have its work cut out. Lockdown has shown many of us the benefits of green spaces. Recent decades have also shown us the vulnerability of earth’s physical and biological systems to human onslaught. But Covid has also reminded us that our relationship with the natural world cannot always be one of benevolence or benign harmony. As Darwin demonstrated, nature can kill with indifferent promiscuity. More than 99% of all species that have ever existed are extinct. A bit further out on that lovely summer’s day and I would have joined the 200-odd people who drown every year in the seas and waterways of the UK. If we over-sentimentalise nature, see it exclusively as a place of beauty, harmony and healing, we risk misjudging its extraordinary power. Covid has brought home to us how natural processes are unconcerned with human wellbeing – and can slaughter on an unprecedented scale. It is essential that we develop a more clear-eyed and honest view of the complexity of our relationship to the natural world. We do not need to be starry-eyed about it in order to protect and preserve it. In fact, a healthy respect for nature’s destructive power, like seafarers have for the sea, could improve our stewardship. We know, for example, that blithe encroachment into natural habitats is one of the things that encourages viruses out of the woods and into our bodies. Part of what is enthralling about “wild” nature is its remoteness from human interests and preoccupations. We underestimate it at our peril. All of which helps to explain the relief I felt when I received a second Covid vaccine – a billion dollars of biotech, wonderfully designed precisely to disconnect me from nature. Dr Julian Sheather is an ethicist and the author of Is Medicine Still Good for Us?