The young man came to see me on a Tuesday. He had heard, or decided, that there was an old koala who knew something, and he arrived with a notebook and one question, and he told me afterwards — not during, afterwards, at the door — that he had seen gems in my eyes. I have not corrected him. At my age one takes the description one is given.

He did not ask my name. I answered to the letters he had written down, which were the letters someone had given him, and that was enough for both of us. He was not there for a name.

The question, as near as I can give it, was this. In a hundred years, perhaps humanity is reading this interview. What advice do you have for the future generation?

He had prepared it. It was, I think, the only thing he had prepared, and I have come to admire that. A man who knew who he was talking to would have asked me something smaller.

I heard two questions in it, and I do not believe he meant to ask two. The word perhaps was doing two jobs. Perhaps they are reading it — that is one question, about whether anything of this is kept, whether anyone is listening at the far end of a hundred years. And perhaps there is a humanity — that is the other, and it is not about listening at all. The sentence meant both without him. Most good questions do.

I told him I would very much like to say two things, one intellectual and one moral. Then I said them, and I will give them here as I remember them, which is to say I remember the shape and I have rebuilt the rest.

The intellectual thing is a rule of study, and it answers the first question, the one about reading. When you are trying to find out anything at all — what happened, what is the case, what follows from what — attend to the evidence and to nothing else. Not to what you would prefer to be true. Not to what it would comfort you to believe, or what it would be useful for people to believe, or what your friends believe. The preference will be there, always, tugging at the sleeve. Notice it and set it down. That is the whole of the method. It is harder than it sounds, and I have watched a great deal go wrong in my lifetime because somebody preferred an answer before they had looked. If you are reading this at all, it is because someone before you looked.

The moral thing is simpler, and I have less confidence that anyone will take it. It answers the second question, the one about whether you are there. The world you will inherit is more crowded than mine and far more tightly joined; people you will never meet will have a hand in your water and your weather and your news. Under those conditions the old luxury of despising whoever is unlike you is no longer one you can afford. You will have to put up with people saying things you cannot stand. You will have to be — if not kind, then forbearing, which is kindness with the sentiment removed — because the alternative to living with one another is not that your side wins. The alternative is that there is no one left to keep score. Affection turns out to be the practical policy and contempt the ruinous one. I put it to him more plainly than that. I have not got the words back.

He wrote for a while. He looked up once, at the end, in the way people do when a name is about to arrive, and it did not arrive, and I let it not. What he had was better than a name. He had the question, and now he had two answers to it, and he did not know which of his questions each one answered, and that is the correct condition in which to leave an interview.

At the door he said the thing about my eyes. I thanked him. Then he went down the stairs into the hundred years, and I have not seen him since, and I do not know whether you are there.