Spend your time on something meaningful. Not on parties, and not on taking it easy. That’s not good enough. […] When you’re young, you think: Let’s party, do drugs, drink, waste it all, right? But as you get older, you look at what you’ve accomplished. And when you get old, you’ve run out of time. You have to ask yourself: Why am I here? Can I contribute anything to humanity, to society, my work?

So given a Time Turner, I would tell my 21-year-old self that personal happiness lies in knowing that life is not a check-list of acquisition or achievement. Your qualifications, your CV, are not your life, though you will meet many people of my age and older who confuse the two. Life is difficult, and complicated, and beyond anyone’s total control, and the humility to know that will enable you to survive its vicissitudes.

I just say, “Follow your instincts.” Don’t feel you have to follow the paths of others, because you may not be temperamentally fitted for it. And so you’ll just harm yourself and your cause and others. But just follow your instinct, and don’t ever pretend to be what you’re not.

Fearlessness means taking the first step, even if you don't know where it will take you. It means being driven by a higher purpose rather than by applause.”

No. You see immediately what your next task will be. I’ve been asked all kinds of silly questions, like “Aren’t you proud? Aren’t you this? Aren’t you that?” I have no time for that, because the next project is upon me.

In my early years it was undoubtedly my father. My father was director of a sanatorium for pulmonary tuberculosis, and at that time there were no antibiotics, tuberculosis was a terrible disease. And, he and I would walk in the woods around that sanatorium and he would discuss his worries about his patients. And from him, I certainly inherited this extreme concern about the well-being of patients. I’ve seen him very happy when he succeeded after months and months of rest and other things to have these people go home cured. I’ve also seen him crying and desperate after trying for a long time and a patient did not get well, and went home to die.

I’ve been mortally opposed to the so-called life-and-death committees that were instituted. When there were many more patients that needed to be dialyzed, and not enough artificial kidneys available, you had the institution of the life-and-death committees. ... Depending on the answer to these questions, he could be dialyzed. Otherwise, he could go to hell. I’ve been mortally opposed to that. When I set up a dialysis center here with a grant from some government agency, I was forced to put in a life-and-death committee, but it never met.

When I was this young assistant at the University of Groningen my responsibility was for four beds, or rather the patients in four beds. That was all I had to do. And, one of these patients was a young man, 22 years old, who slowly and miserably died from renal failure. He became blind, he vomited, and it was a miserable death. And I, as a very, very young physician, had to tell his mother, in a black dress and a little white cap like the farmers have, that her only son was going to die. I couldn’t do a damn thing about it. So, I began to think, “If I could just every day remove as much urea as this boy creates, which is about 20 grams, then the boy could live.” Well, he died, but I began to work on that.