“When you realize you are mortal you also realize the tremendousness of the future. You fall in love with a Time you will never perceive,” the great Lebanese poet, painter, and philosopher Etel Adnan wrote in her beautiful meditation on time, self, impermanence, and transcendence. It is a sentiment of tremendous truth and simplicity, yet tremendously difficult for the mind to metabolize — we remain material creatures, spiritually sundered by the fact of our borrowed atoms, which we will each return to the universe, to the stardust that made us, despite our best earthly efforts. Physicist Alan Lightman contemplated this paradox in his lyrical essay on our longing for permanence in a universe of constant change: “It is one of the profound contradictions of human existence that we long for immortality, indeed fervently believe that something must be unchanging and permanent, when all of the evidence in nature argues against us.”

Two millennia earlier, before the very notion of a universe even existed, the Roman emperor and Stoic philosopher Marcus Aurelius (April 26, 121–March 17, 180) provided uncommonly lucid consolation for this most disquieting paradox of existence in his Meditations ( | free ebook) — the timeless trove of ancient wisdom that gave us his advice on how to motivate yourself to get out of bed each morning, the mental trick for maintaining sanity, and the key to living fully.

Eons before the modern invention of self-help, the Stoics equipped the human animal with a foundational toolkit for self-refinement, articulating their recipes for mental discipline with uncottoned candor that often borders on brutality — an instructional style they share with the Zen masters, whose teachings are often given in a stern tone that seems berating and downright angry but is animated by absolute well-wishing for the spiritual growth of the pupil.

It is with this mindset that Marcus Aurelius takes up the question of how to embrace our mortality and live with life-expanding presence in Book II of his Meditations, translated here by Gregory Hays:

The speed with which all of them vanish — the objects in the world, and the memory of them in time. And the real nature of the things our senses experience, especially those that entice us with pleasure or frighten us with pain or are loudly trumpeted by pride. To understand those things — how stupid, contemptible, grimy, decaying, and dead they are — that’s what our intellectual powers are for. And to understand what those people really amount to, whose opinions and voices constitute fame. And what dying is — and that if you look at it in the abstract and break down your imaginary ideas of it by logical analysis, you realize that it’s nothing but a process of nature, which only children can be afraid of. (And not only a process of nature but a necessary one.)

In a sentiment Montaigne would echo sixteen centuries later in his assertion that “to lament that we shall not be alive a hundred years hence, is the same folly as to be sorry we were not alive a hundred years ago,” Marcus Aurelius rebukes our pathological dread of death by demonstrating how it ejects us from the only arena on which life plays out — the present. Long before Rilke made the countercultural, almost counterbiological observation that “death is our friend precisely because it brings us into absolute and passionate presence with all that is here, that is natural, that is love,” he adds:

Even if you’re going to live three thousand more years, or ten times that, remember: you cannot lose another life than the one you’re living now, or live another one than the one you’re losing. The longest amounts to the same as the shortest. The present is the same for everyone; its loss is the same for everyone; and it should be clear that a brief instant is all that is lost. For you can’t lose either the past or the future; how could you lose what you don’t have?

Remember two things:

1) that everything has always been the same, and keeps recurring, and it makes no difference whether you see the same things recur in a hundred years or two hundred, or in an infinite period;

2) that the longest-lived and those who will die soonest lose the same thing. The present is all that they can give up, since that is all you have, and what you do not have, you cannot lose.

He concludes by summarizing the basic facts of human life — a catalogue of uncertainties, crowned by the sole certainty of death — and points to philosophy, or the love of wisdom and mindful living, as the only real anchor for our existential precariousness:

Human life.

Duration: momentary. Nature: changeable. Perception: dim. Condition of Body: decaying. Soul: spinning around. Fortune: unpredictable. Lasting Fame: uncertain. Sum Up: The body and its parts are a river, the soul a dream and mist, life is warfare and a journey far from home, lasting reputation is oblivion.

Then what can guide us?

Only philosophy.

Which means making sure that the power within stays safe and free from assault, superior to pleasure and pain, doing nothing randomly or dishonestly and with imposture, not dependent on anyone else’s doing something or not doing it. And making sure that it accepts what happens and what it is dealt as coming from the same place it came from. And above all, that it accepts death in a cheerful spirit, as nothing but the dissolution of the elements from which each living thing is composed. If it doesn’t hurt the individual elements to change continually into one another, why are people afraid of all of them changing and separating? It’s a natural thing. And nothing natural is evil.

Complement this portion of the altogether indispensable Meditations with psychoanalyst Adam Phillips on what Freud and Darwin taught us about how to live with death, neurologist Oliver Sacks on gratitude, the measure of living, and the dignity of dying, and philosopher, comedian, and my beloved friend Emily Levine on how to live with exultant presence while dying, then revisit two other great Stoics philosophers’ strategies for peace of mind: Seneca on the antidote to anxiety and Epictetus on love, loss, and surviving heartbreak.