For centuries, the walls of museums have been filled with masterpieces. But what really makes a masterpiece? Is it its beauty? Its cultural importance? Over the past year, four art experts have been collaborating to create an algorithm that can find out.

The four aren’t museum curators or art critics. They’re not even art historians. They are data scientists at Google. And their system — which they call the Artistic Assessment of Images through Neural Estimation and Regression to the origin (or AARON for short) — will be added this month to Google Images, where it will begin ranking images on a scale from zero to one. It is not yet clear if the scale will be reflected in search results, but it will rank images used in Google Image searches, alongside human-made results like those from Google Cultural Institute, Wikipedia and other image repositories. The goal is to help users make better choices about which images are worth their time to look at and which are not. “We wanted to build more machine intelligence into our image-search capabilities,” said Michael Tyburski, a data scientist on the project and a co-creator of AARON. “Google has tried different things with art in the last couple years: we had Google Art Project

What do you need to do to make a masterpiece? What was it like to be alive then? How did they think about what they were doing? Three experts—a curator, an art historian, and a critic—discuss the mysteries of their field.

What is it that makes one piece of art better than another? It’s not a simple question. People can argue about music, or movies, or even painting for hours. And yet it’s hard to name a single painting that everyone agrees is greater than all others.

The experts we talked to—and there are many in this field—share the same goal: come up with the list of best works of art ever made. And yet this goal raises more questions than it answers. What is “best”? How do you define that? Does such a thing even exist? Or is it just something people say when they can’t decide what they like?

These aren’t just academic questions. In fact, they’re surprisingly practical ones, because having a sense of what the best works are helps us understand our own culture better and learn from the people who came before us.

In fact, if the Louvre were to create a museum of the most important works of art in history, he would be the curator.

The reason for this is that his job has little to do with popularity or taste. The job of an artwork curator is to choose the best works of art. How one knows what makes a work of art best is something that experts like Mr. Baxandall have been trying to figure out for centuries. The Louvre’s curators may be able to tell you what they think is good, but they don’t know why it’s good.

Taste, after all, is highly personal; it’s one thing to say that you like the Mona Lisa or Peter Paul Rubens’s “The Descent From the Cross,” but quite another to say why these are better than other paintings. The problem is that “better” is always a relative term — not just in terms of artistic merit but also in terms of cultural relevance and historical context. What’s better for you might not be better for me.”

What makes a masterpiece? The experts who make art history’s canon try to answer this question, and want you to weigh in too.

Tate Britain’s “Turner Prize” exhibition is a radical departure from traditional exhibitions of the prize’s winning artists, which typically present the works of one artist in chronological order. Instead, Tate Britain has chosen five “masters” of contemporary art — Tracey Emin, Anish Kapoor, Grayson Perry, Helen Marten and Richard Wright — and asked them what they thought were the most important works made since 2000.

The resulting show is a conversation between the five artists about their choices. It also reveals their different approaches to art making: Emin’s smelly My Bed; Kapoor’s massive sculpture Marsyas; an installation by Perry that explores his dual identity as an artist and gay man; Marten’s delicate drawings examining love and loss; and Wright’s haunting film work.”

There’s a famous anecdote about Bob Dylan, who was asked when he first realized he was “a poet.” “Oh, I’ve always been a poet,” he replied. “I just didn’t always know it.”

This is how I feel about writing. From the time I was a child, I knew something about words and how to use them. But I did not consciously decide, one day in high school or college, that I would devote my life to words. It took me several decades to realize that this is what I do–and had been doing all along.

Toward the beginning of my second decade as a reporter and editor at The New York Times, in 1999, I became curious about who is considered the greatest living writer in any language and why they are considered so. In short, I wanted to know: What makes a masterpiece? Who decides? And among those who decide, what are their criteria?

To achieve immortality, a work must be new and also good. “New” is not complicated. A work must interrupt the flow of art history in some way. It must force us to look at the world in a different way.

A work’s greatness, however, is more complicated. The only universal criterion for greatness is time. Greatness can only be established once a work’s innovations have become so familiar that they are no longer disruptive or even noticeable. Even the experts who create best-of lists have trouble agreeing on what makes something great–or even on whether something is truly good at all–because they can’t yet see how its innovations will affect the future of art.

GREATNESS IS NOT MERELY CHANGING THE WAY WE SEE THE WORLD; IT’S CHANGING THE WAY WE SEE EVERYTHING FOREVER.

It’s a question that reputedly keeps Pablo Picasso and Andy Warhol up at night. What makes a masterpiece? And the more you think about it, the more elusive the answer seems.

Here are just a few of the opinions of some experts on the issue:

“It starts with a feeling,” says George Lucas, who is no stranger to classical mythology. “You start with an emotion, then you build on that.”

“A masterpiece is a unique product of its time,” explains art historian Sir Kenneth Clark. “I don’t believe in judging art from other periods by our own standards.”

“I think it has to do with balance,” suggests author Salman Rushdie. “You have to create something that is well-balanced, that’s unified, that hangs together.”

“The criteria for what makes something great is different for everyone,” says painter Chuck Close. “When I’m painting my own pictures, I can do whatever I want — but when I have to choose what goes in an exhibition, I have to consider whether it will be good for other people to see.”

The best sort of masterpiece should delight everyone yet speak specifically to each individual. It should be difficult yet not overly challenging. It should give pleasure and make demands on