Recently in Madrid I stood for a while in front of Picasso’s Guernica, trying to explain it to Mozart. I often speak to my biographical subjects while I’m writing about them. A while back I spent some time imagining playing Louis Armstrong recordings for Brahms. I felt sure he would catch on and like it. After all, he loved gypsy music and was fascinated the time he heard an American girl playing ragtime on banjo at a party.

Talking to Mozart about Guernica was a dicier business. I wasn’t sure he could ever get his sensibility around it. There are so many issues at play in that soul-searing painting, done soon after the atrocity that inspired it: the fire-bombing of a Basque village by Nazi warplanes in support of General Francisco Franco. He ordained, in other words, the mass murder of his own people, most of them women and children because the men were off fighting in the civil war.

I’d begin by showing Mozart a photograph. I’d tell him that when photography appeared, painting was no longer required to represent reality. Now painting could take off on its own–including, if it wanted, creating images free of representation. In other words, painting could explore things that only painting can do. Art could distort reality at will, or depart from it entirely and treat painting as an abstraction like instrumental music, or use it to portray dream or nightmare images, or pure states of mind and emotion.

Already I might have lost Mozart. He was so tied to his time, to convention, to the social world his music was part of. I don’t think he ever put musical and operatic conventions aside. He made use of conventions—musical, dramatic, operatic—to the end of his life. What he did was to go through convention and come out the other side, wielding it as part of his singular voice. So Mozart might never be prepared to understand modernism in art, because he was not interested in revolution. He was interested in using the status quo for his own purposes.

But let’s imagine that in the middle of my explaining the art of the early 20th century that Mozart hadn’t run off screaming, that he remained, skeptical but ready to hear more. I’d show him Picasso’s cubism, how it distorted reality while remaining true to it, and how those distortions could be expressive, human, even as the works bent and folded matter like a sheet of paper. I’d show him Picasso’s cubist paintings of a woman crying, and point out that you can see her pain and can also make out who the woman is—Picasso’s lover Dora Maar.

Then I’d have to show Mozart airplanes, particularly warplanes, and what bombs do. I would show him film of airplanes dropping bombs. Not inured to these things as we are, Mozart would be shocked and stunned. He would see an evil he could scarcely comprehend, scarcely encompass. His view of war involved glory and heroism and grand uniforms. Planes dropping bombs have no glory, no heroism; their purpose is slaughter. I can’t imagine Mozart’s kind of art could encompass that degree of evil.

Now I would tell him about the bombing of the village of Guernica by German airplanes, sanctioned by Franco. Finally I would show him Picasso’s painting. It would need to be in person, standing in front of that massive, horrifying canvas.

If he had followed me this far, I think on some level Mozart would understand. How could he not? It is a painting whose essential point is inescapable. I’d explain to Mozart that in this painting the distortions of cubism are put at the service of portraying unspeakable violence and pain, a world broken and weeping and screaming. Women scream, nature screams, the virile bull screams. On the ground lies a shattered statue, one disjointed hand clutching a broken sword. Art is broken too. And the statue is screaming.

All very well, Mozart would say, but this painting is like the daubing of a little child! Look, you can even see paint dripping! I would respond by showing him the work of Picasso in his teens, when he could already draw traditional representation remarkably well. I’d explain that his skill at drawing stayed with him, but that he came to feel that sometimes he had to tear it up, on the surface put it aside, sometimes draw with all his skill as if he were a child. This would be another point where Mozart might throw up his hands, at the idea that you would use your skill to mask your skill. To Mozart, skill meant a great deal. In your work you didn’t boast about it, but you didn’t hide it either. My only response would be that if Guernica were painted any other way, it would not have the same kind of power. Nor would a photograph of the massacre.

So there we would be, Mozart and me, contemplating the contrapuntal elements of a legendary work. If it was a typical day in the Reina Sophia museum, we would be surrounded by a crush of viewers. In these situations I remember what my brother Charles once observed on a crowded day at the Musée d’Orsay in Paris: “Art is being appreciated to death.”

Here in front of Guernica nearly everyone under thirty is fingering a cell phone, even though it’s not allowed to take a photo of the painting. The whole museum is full of young people sitting and standing around, staring at phones more than at art. Inevitably, sadly, all this is part of the experience too. I’d tell Mozart that it would be similar at a modern performances of one of his operas: crammed with people, many of them anxious to get back to their cells. I imagine him asking if any of these people looking at the Picasso actually feel it, resonate with its unimaginable pain. Or is it just a thing to do, a famous landmark to check off the list, a destination before lunch. I’d tell him I don’t know, I hope some of them do feel it, even some of the ones clutching phones.

In any case art has changed and changed again since Mozart’s day, in ways he could not have imagined. And inevitably those changes have dragged his art along with them. The connection of art to the world has changed, everything from “art for art’s sake” to bloody involvement in the horrors of the day. Still, musical responses to war are not new. Haydn’s Mass in Time of War and Beethoven’s Missa solemnis are both shattered during the prayer for peace in the Agnus dei by sounds of war that tear the music apart—as the statue in Guernica is blown apart. But Picasso within the language of cubism has reached a depiction of pain and tragedy more raw, more immediate, than almost anything before. (The pictures of Goya during the Napoleonic Wars are among the few comparable artworks.)

There I would leave Mozart to his thoughts. For myself, every time I see Guernica I think of when I saw it in Madrid in 1981, soon after it was returned to Spain from the U.S. It was residing in its own small building, behind inches of bulletproof glass, with two soldiers flanking it holding machine guns. Francoistas had vowed to blow it up. Franco was dead then, but his spirit lived on. So much for the idea that art is irrelevant to the real world.

I thought once again about political art. The part of the Reina Sophia Museum where Guernica lives is full of works that amount to a sustained scream of outrage against Spanish Fascism and its violence. The impact of those works ranges from indifferent to compelling, though none are on the level of Guernica.

The thing is, I’ve always been skeptical of political art. For starters, I don’t buy the old socialist line that “all art is political,” because I am skeptical of any idea that starts with “all art.” Some art is intentionally political, polemical, didactic, but much of it isn’t. I don’t know how much art can change people’s minds about anything. Political art tends to be a matter of preaching to the choir; the people who like it already believe what it’s saying. There’s also a risk of sheer scam in political art: if you don’t like my performance piece against war or racism or sexism, then you must approve of those things. I half-subscribe to Joseph Brodsky’s observation that, “If a poet has any obligation toward society, it is to write well.” I would have said: “The poet’s first obligation to society is to write well.” Sometimes other obligations follow.

All this is not a simple matter, which is why I endlessly turn it over in my mind. After all, I’ve written a piece of music called They Who Hunger and another called They That Mourn, the latter in memoriam 9/11. I suppose what I believe is that a response to suffering or evil that boils up from inside an artist is an authentic work. It’s artists responding to the world by doing what they do. All the same, to make a protest meaningful you still have to write well, or paint or compose well. Picasso’s response to evil is immortal because it’s a great painting by a great artist, not because of the protest, which is intentionally so simple a child can understand it.

If Mozart had not run away during my exposition of the painting, I’d explain to him that my country is living with encroaching threats of the kind that emanate from a rot at the top. And artists haven’t been responding to it with the full force of art, as Picasso did immediately after learning about the bombing of Guernica. Maybe somebody will slather a political slogan across a cardboard box or make a digital screen crawl of it—I’ve seen both—and the political message will be the entire point. The easy, lazy point. Picasso labored at white heat for a month on Guernica, revising it again and again (there are photos of the process), because he insisted it must work not just as statement but as art. Surely that’s why Guernica is one of the mightiest works of its kind.

Here’s another example of what I mean. I once heard on radio a series of revisions Henry Thoreau made to a line in Walden. It began with an observation in his journal, after a party. I don’t remember the exact words, but it was something like, “I noticed that most of the people there put on a convivial face, but it was clear that none of them were really happy in the least, yet they never talk about it.” Then he began working on the idea. As I remember there are nine surviving drafts of it. What he ended up with is one of the most famous phrases in the language, and one of the most tragically wise: “The mass of men live lives of quiet desperation.” That phrase does not say anything the first version didn’t, but it says it once and for all. We spend our lives learning its truth. And remember what Picasso said: “Art is a lie that shows us the truth.”

Art done well has tremendous power, political and emotional, but there’s not enough of that around these days. Artists of our time, as far as I’ve seen anyway, have been useless at fighting the malaise of our time, the growing human cost, the rot of corruption and lies—lies that are intended to destroy the truth. At least the U.S. is not Nazi Germany yet. We won’t routinely be killed for telling the truth—not yet.

All this would surely be too much for Mozart. He would first have to understand a new scale of evil, then refashion his conceptions of art to deal with it. It would likely be too much, even for him. But we have the knowledge and the means, the technique to respond to psychological and physical violence. Yet we mostly complain instead of create. Visual art these days is more a matter of fashion and money than anything else. What’s our excuse?

These thoughts, standing in front of a devastating painting in Madrid.