ADAMS A really great text is just so generative; it produces the best music. If I have a concern about some operas these days, it’s that the texts are just not good enough. It doesn’t have to be someone with a deep literary background; it can be a David Bowie or Brian Eno. The great thing about American music is the total bleed-through of, if you want to call it that, high or low, popular versus art. I think both Philip and I share this. We have very loose filters in terms of classification.

When did you first hear each other’s music?

ADAMS The thing I remember most vividly is a tour of the ensemble doing excerpts from “Einstein on the Beach,” which I heard in San Francisco sometime in the 1970s. Then I actually conducted quite a bit of his music — a little piece, “Facades,” and then I think we did the very first performance of parts of “Akhnaten” in L.A. on a Phil program, 50 minutes’ worth. I did the Ninth Symphony, again with L.A., and then this.

I came of age during what we now call the bad old days, when the world said you had a choice between European modernism and its American version, or Cagean aesthetics. Hearing Philip’s music and Steve [Reich’s] music was this wonderful, new possibility of a language that embraced both tonality and sort of living with a pulse, new, original and fresh.

GLASS I was very much taken with hearing John’s work — of course, “Nixon in China,” we talked about a number of times. It’s not enough to create a style of music or identity of your own; what you really want to be is in the company of other people. It’s more meaningful to be part of a large group of people sharing ideas.

He was the first time I met someone who wasn’t part of my immediate generation but had the interest and talent. How many operas do you have now? Five or six?

ADAMS [Laughing] Not as many as you do! [Depending on how you count, Mr. Glass has composed nearly 30.]