Marcus Aurelius reminds us in this text from his Meditations that everything you experience, including your own existence, is in constant flux. Your sensations, which are often deceptive, offer you only a limited view of reality.
And yet, in the midst of this impermanence, there is an anchor, a constancy that you can achieve, and that is through philosophy. But not through a philosophy that is bogged down in fuzzy and intellectual abstractions; but through a lived philosophy that is practiced every day in the deep awareness that you are part of a greater whole.
This philosophy,
is stoicism.
~
“Of man's life, his time is a point, his existence a flux,
his sensation clouded,
his body's entire composition corruptible,
his vital spirit an eddy of breath,
his fortune hard to predict,
his fame uncertain.
Briefly, all the things of the body, a river; all the things of the spirit, dream and delirium; his life a warfare and a sojourn in a strange land, his after-fame oblivion.
What then can be his escort through life?
One thing and one thing only, Philosophy. And this is to keep the spirit within him unwronged and unscathed, master of pains and pleasures, doing nothing at random, nothing falsely and with pretence; needing no other to do aught or to leave aught undone;
and moreover
accepting what befalls it,
that is,
what is assigned to it,
as coming from that other world from which it came itself.
And in all things awaiting death, with a mind that is satisfied, counting it nothing else than a release of the elements from which each living creature is composed. Now if there is no hurt to the elements themselves in their ceaseless changing each into other, why should a man apprehend anxiously the change and dissolution of them all?
For this is according to Nature; and no evil is according to Nature.”
~
In what nature does,
there is never anything wrong.
Recognize the impermanence of all things as an opportunity for growth, not as a source
of fear
or regret.
The only thing you can really control is your inner reaction to life's events.