As I become more experienced in surgery, I feel more confident in my ability to understand what is happening, and to even assert what I think will happen, or should happen.

However, the opposite has also been true, in that the more I have learned, the more I find that I will never be able to understand everything. I have taken care of healthy patients whose condition takes a rapid turn for the worse. I have also seen patients recover from circumstances that I absolutely believed to be irrecoverable.

Recently, I was standing outside the room of a patient who I believed would pass away imminently. The patient’s death seemed absolutely certain to me, based on everything I have seen. In fact, all of us involved in the patient’s care strongly agreed.

But that patient continues to survive to this day, and I regret my premature judgment.

Thinking about how these experiences have shaped me in the last few years reminded me of a parable I grew up reading in South Korea. It’s called “The old man lost his horse” and dates back in Asian literature to the second century B.C.

One day, a horse belonging to an old farmer ran away and his neighbors gathered to lament his terrible loss. But the old farmer simply asked them in return, “Who knows if that won’t bring you good luck.”

Sure enough, a few months later the horse returned with a group of other strong horses. His neighbors again gathered to congratulate him on such good fortune, but he did not share their sense of certainty, because, soon after, his son fell while riding a horse and broke his leg, maiming him.

His neighbors felt that surely this time the old farmer must regard this as a tragedy, but he remained neutral. “Who knows if that won’t bring you good luck.”

A year later, barbarians invaded the border, leading to the conscription and deaths of most able-bodied men, but the father and son both survived the war.

The point of the parable is that the framework of human perception or prediction is limited. Thus, immediate judgment can often turn out to be incomplete or false.

Reflecting on the early years of residency, I see much of my past self in the neighbors from the parable, jumping to conclusions reactively, proclaiming that something is “right” or “wrong,” “possible” or “impossible.” I even believed for a while that the point of training was to pursue a sense of certitude and authority.

But as I see fortune wash back and forth over my patients, I am beginning to find within myself more equanimity.

Situations constantly prove to be more complex and nuanced than I originally believed. I am reminded of countless headlines over the last two years that have promised the return of normalcy as the world finds itself amidst the worst COVID-19 surge yet.

Experience has taught me to be less sure of anything, and humbler in my judgment.

Now, when I encounter a situation at the hospital or in my life where I would have previously claimed to know the answer, I hold back a little bit more, a little while longer, because who knows what may prove to be true.

Jason Han is a cardiac surgery resident at a Philadelphia hospital and frequent Inquirer contributor.