When I was about ten my older brother Mick asked me a question. It was a hot, aimless, endless summer day. Dad was marching up and down the lawn with that ancient and electrically suspect mower he had; I was playing my usual game of standing in the snaking cable coils and leaving it as long as I could till I jumped free. I was surprised when Mick suddenly appeared. He was usually upstairs studying, and anyway, he didn’t usually have all that much time for me. We fought a lot – mostly over wall space, things like that. It was a small house, too many kids, not enough money. A solid, semi-detached kind of pressure cooker with a garden and a garage full of bikes. Mick wanted to ask me a question, and I could tell from the way he asked it – fidgeting from side to side, hardly able to wait for me to answer – that there was a lot more riding on this than just science. He had a point to make and scarcely needed me there to do it. I was below him in the pecking order. It was the way these things went. 

This was the question he asked me:

What are roses for?

‘I don’t know. To be colourful. And beautiful. And attract bees.’

I added the bees to make myself seem smarter and less of a target.

‘No,’ he said. ‘Roses are there to make other roses.’

He stared at me, daring me to say he was wrong. And I wanted to, I really wanted to. Only… I didn’t know how. It sounded crazy. What did he mean? Was he right? Was that really it? One long line of roses, from the beginning of time to the end? I mean – Why bother? Wouldn’t it be easier just to never have roses? 

Recently it all came back to me, that little front garden, Dad shouting, tripping over the wire, as me and Mick tried to kill each other among the roses.

It came back to me recently because I got stuck in the same way, trying to understand what a virus was, what it meant, what it was for. For making other viruses. Really?

Of course, one of the essential questions about viruses – the most basic, Mick-type question – is whether they’re alive or not. And I suppose using Mick’s rose protocol, you’d have to say they were alive. Virus begets virus. The life principle satisfied. That’s it. The sucker punch school of philosophy.

Only – that’s not it. 

The accepted view is that a virus is non-living. Which is not the same as saying it’s not alive. As always, there’s a hinterland of meaning and ideas behind these words, and they quickly lose their patency. 

Technically speaking, though, a living organism is supposed to have seven characteristics: Movement, Sensitivity, Respiration, Nutrition, Excretion, Growth and Reproduction. A virus only has one of these – and even that in a qualified way.

A virus is not capable of independent movement, relying instead on sneezes or random hook-ups, the innocent winnowing of tracheal villi down a particular respiratory tract. 

It’s only sensitive to its environment in that it’s vulnerable to UV light or excessively dry conditions, for example. But some viruses are tougher than that. An extinct form of giant virus – ‘giant’ in microscopic terms – was recently revived after being dug out of the Siberian permafrost 30,000 years after it went in. Another virus was discovered biding its time inside bacteria that live around deep ocean thermal vents. 

A virus doesn’t breathe, eat or excrete waste products because it doesn’t need to – which is a pretty useful adaptation, when you think of it. As humans, we need energy to live. We do that by metabolising oxygen and food to create ATP, the chemical compound that powers our complex systems. A virus simply taps into that, using our energy reserves and our cellular machinery to replicate itself. 

Neither does it grow, designed instead to float around until it finds a host cell to make copies of itself, cookie-cutter style, each version a clone of the original. 

But not exactly. Because although this isn’t reproduction in the usual sense, some genetic change can happen – and in some cases, like flu, very quickly and often. Sometimes you get two similar viruses with slightly different RNA or DNA that recombine in the host cell to produce a genetically novel virus – which either does well or it doesn’t, in the evolutionary way of these things. Which is why viruses are so successful, or such a problem, depending on your viewpoint. 

So is a virus alive or ‘non-living’? And if it’s really ‘non-living’, does that put it into the same category as – say – a rock?

The question is more nuanced. A rose is made of atoms arranged in a particular molecular way, as am I. Some of those molecules are repurposed into genetic material, determining whether we grow thorns or thumbs. So in that respect a virus is the same – made of atoms, some of them bent into intricate RNA / DNA ladder strings, determining whether they invade human lung cells or thermal vent bacteria. The only difference between the rose, me, a virus and that rock, is that whilst we’re all made of atoms, me, the rose and the virus have that specialised genetic material and the rock doesn’t. A rock is a passive expression of molecular stuff, sculpted by geological processes into the thing you pick up to chuck at your brother. 

I’m not a scientist. I quickly get out of my depth. All I’m left with is an overwhelming sense of the universe’s richness and complexity. It seems to be reaching out over trillions of years from one critical moment of expansion through the arcane laws of thermodynamics to some other state,a statistically driven force scattering infinite manifestations of energy through everything, every last particle of existence, until some kind of balance is reached and nothing further is possible. So you get viruses, and roses, and two brothers fighting on a front lawn, and that kind of endless summer day when nothing seems to happen, and everything does.