“Why are you going upstairs one at a time?” came the question from behind me as I slowly made my way to a meeting at church.

I explained that my left knee hurt when I put weight on it to go up and down stairs, so I was babying it.

“What gives you hope that it will get better?” my interlocutor, a former nurse, pressed.

I could have said, “wishful thinking,” which does form part of my reason for believing my knee will eventually hurt less. But instead I said previous experience had shown me that taking it easy helped the knee improve.

Of course, that's not much of a basis for thinking that, now that I'm older than I've ever been before (though younger than I'll ever be again), my knee will still respond so well to rest. But wishful thinking keeps me going up and down stairs one at a time, taking aspirin and trying to be good to my sore joint.

It's true what they say about how getting old is not for sissies. It's also true that the alternative is even less appealing, at least for now, at least for most of us.

And I'm lucky. A couple of friends have had cancer scares recently, and don't know yet how scary things may get. Others are worried about their parents, partners, etc. Life is precarious.

And yet, every time we're confronted with the precariousness of life, its utter fragility, we are somehow surprised, as if disease, decay and decrepitude weren't the natural order of things. As if impermanence weren't at the very heart of existence, the very thing that makes it precious.

Of course, life is also very resilient and durable. Look at a forest. Burn it down and new life arises from the ashes. Everywhere you look in nature, life is being born from things that are dead or dying; plants and animals are adapting as conditions change. A tree will grow right out of a rock if it has to. Weeds spring up through cracks in city pavement.

Only human beings are fooled into thinking that the ephemeral won't change, that what lasts – life itself and the indomitable urge to live – can be destroyed. Like the fish in the sea, we swim in time without noticing it around us, and so are deluded by it.

But there is an essence in us that exists beyond time, that is one with everything that has ever existed, or ever will. I get a glimpse of that essence when I can be still in nature and feel the pulse of life around me. I close my eyes and send my hearing out and out, listening to the layers of sound, inhabiting all of that space, expanding with each layer.

When I return to myself, I am anchored in the present. Anchored in Life.