“As we grow older, the world becomes stranger,
The pattern more complicated of dead and living;
Not the intense moment, isolated, with no before and after,
But a lifetime burning in every moment;
And not the lifetime of one man only,
But of old stones that cannot be deciphered.”
— T.S. Eliot, “Four Quartets (East Coker)”

I TURNED 51 A FEW DAYS AGO. Passing into my fifties has made me take stock of where I am in life, and where I’ve been.

I think back to me at 18 years old, and for all the tumult of being that age, my life stretched before me with seemingly limitless, even frightening, promise. I had not yet known failure of any significant scope. I had yet to have my heart broken. I was going to change the world, dammit, and I wanted answers, and clear ones at that.

Things seemed simpler, or maybe it was easier to convince myself they were. I had yet to gain any appreciation of the complexity — the irreducible mystery — of life, an appreciation that is an essential ingredient of wisdom. Men in my peer group typically did a stint in the armed forces, and I enlisted in the Army with scarcely a thought to the justice of my country’s causes, or the effects of propaganda on my decision-making. Given the regularity with which this country sends young men into battle, it was sheer, dumb luck that I happened to serve between wars.

If my body ached, it was my own damned fault (perhaps with a little help, occasionally, from rum). Time had yet to start insisting on its supremacy, had yet to supply me with the pains of its passage — pains of both body and mind. In my early twenties, I could spend an entire four-day pass partying and carousing, yet be up at 5 a.m. and ready to run 5 miles and do hundreds of push-ups the day after returning to the barracks.

I miss the resilience of my younger body. I miss the way practically every experience had an air of bewitching novelty, and my first realization that I could make my life whatever I wanted it to be, and having all the time in the world to correct any mistakes I made along the way.

Middle age is bittersweet — it is wisdom, but also it is absolute decline. Your sense of time both expands and grows short. You realize 30 years is not as long ago as you used to think, but in the other direction death comes rushing toward you ever more tangibly.

Death, as an actuarial matter, is very possibly closer to me in the future than high school is in my past, and the years seem to tick by in the span that six months used to occupy.

I’ve decided to skip the Corvette-and-hairpiece, clinging-to-youth thing some guys do in their middle years, but I now understand what a powerful attractant nostalgia can be for guys my age.

It’s all death-denial. The negotiations have begun, but I already know I will lose and death will win, as it must — as it needs to.

I understand the temptation in men my age to vainly try to hold on to a mercilessly vanishing youth. But returning to my youth would require me to surrender wisdom, too, and more; being 18 again would mean the erasure of some memories by which I mark the years, experiences that have given me a deep and abiding gratitude.

I would lose the morning I got up before a very frigid dawn, walked out into a meadow and watched the sun come up over Vermont mountains, casting amber light on frosty brittle grass and fiery autumn woods.

I would lose my first real love, the taste of our first kiss, and the way her face looked that one night as the moon lit the contours of her cheeks with blue and sacred light. I would lose how much I loved her. I would lose the pain of our parting — is there anything worse than heartbreak? — but also the crucial lessons that pain taught me.

I would lose one of the last conversations I had with my cancer-wracked father before he died 17 years ago, when I held his hand as he laid in bed and he told me he thought I was the most Irish of his children (his parents had been Irish immigrants), and suddenly I realized I had always wanted him to say that.

I would lose the moment, praying the Stations of the Cross, when Christ shared His pain with me with such irresistible tenderness that I wept and gave Him some of mine.

Bob Seger once sang, “I wish I didn’t know now what I didn’t know then.” I get what Seger was saying, but for all the melancholy regrets, the bodily aches and increasing limitations that characterize middle age, I’ll keep the lessons I’ve learned.

The first half of life is about getting a grip — on life, on who you are and where you fit. The second half is about learning to accept life’s limits, and finding gratitude. Ultimately, it is about letting go.

Matt Talbot is a writer and poet, as well as an old Benicia hand. He works for a tech start-up in San Francisco.