A chair is a difficult object. A skyscraper is almost easier.” — Mies van der Rohe.

Van der Rohe, as with Eames, Gehry, Hadid, Libeskind, Corbusier, and Breuer: if they’ve designed a big building, chances are they’ve designed a thing on which to sit.

The chair presents an interesting design challenge, because it is an object that disappears when in use. The person replaces the chair. So chairs need to look fantastic when empty, and remain invisible (and comfortable) while in use.

Again and again, new chair designs rise to this challenge, and more are coming out all the time. Some have argued that there are too many chair designs in this world, including one of the greatest headlines from the Onion: “Report Confirms No Need To Make New Chairs For The Time Being.”

Yes, there are already a lot of chairs, but our needs from chairs are constantly changing. Consider the café: they used to be places for talking; now, they are places for working. People use the space differently, and the furniture must be adapted to serve the evolving use of a space.

Throughout our lives, we have been told to sit down. In school, in the office, in the polite company of a dinner party. In a car or a plane or a bus or a movie. We spend a lot of time in chairs. Which has lead to a lot of talk lately about the unhealthiness of chairs.

Sitting is the New Smoking, says The Huffington Post, CBS News, Wired, TIME, and The Mirror.

All these new studies and scary headlines have created demand for new ways to sit. There are now medicine ball chairs, adjustable chairs, standing desks, treadmill desks (not to mention fetal position desks).

The chair backlash is upon us. Berkeley architecture professor Galen Cranz saw it coming.

In 1998, Cranz published The Chair: Rethinking Culture, Body, and Design. The argument of The Chair, essentially, is that we should stop sitting in chairs. Or at least for so long. Cranz says three hours is the maximum time a body ought to spend sitting each day.

In her own life, Professor Cranz takes innovative chair sitting to another level, by attempting to “eliminate all conventional chairs.” Her house is full of floor cushions, tatami mats, and lots of hybrid chairs, such as a medicine ball on an office chair chassis, and one that looked like a sleek, pared-down horse saddle.

When she’s out in public and gets tired, Cranz opts to kneel, or squat, or lie down. “I lay down in a bank and someone asked me if I was having a heart attack,” Cranz says. “I understand. But I said no, I’m fine, I’m resting because the line is so long!”

It takes gusto to avoid chairs.

Cranz explains that we all got suckered into the seated position once we got off the farm:

In the 20th century we moved from being an agricultural economy, where most people worked on farms, then we moved into a manufacturing economy, where a lot of people worked in factories. Some sat, some stood to work the machines along the conveyor belts, and then we moved into a service economy. And that seems to be where the chair really took off and became the dominant apparatus for our lives.

When we settled into the service economy, sitting became the way to type file and fill out paperwork. This is when office chairs become the chairs in which people spend most of their time.

Until very recent history, office chairs weren’t made to fit your body. They were made to fit your job. There were managerial chairs, middle managerial chairs, secretarial chairs—the sizing was completely status-dependent. This meant that in some cases you could have a 120 pound executive sitting in a gigantic chair and a 160 pound assistant secretary sitting in a tiny little chair. For the most part, status trumped ergonomics.

Then, in 1992, the Aeron chair was born. It came only in three sizes: small, medium, and large.The Aeron chair brought in an age of egalitarian office ergonomics, all made visible by the chair’s swivels and adjustment technology. All workers were equal in their Aeron chairs. And the Aeron chair defined what an office chair ought to look like.

Though expensive, the demand for the chairs was extraordinary. Perhaps, in part, because of a growing number of repetitive strain injury lawsuits. Companies suddenly found it cheaper to buy fancy adjustable chairs than to pay for legal settlements or medical bills.

But fixing the chair doesn’t totally solve the problem. It turns out that the chair has an accomplice: the desk.

Flat surfaces force you to bend forward. Even if you have excellent posture, its hard to avoid leaning over your keyboard, or your dinner, or your book. The spine curves into a big C-shape, which is awful for your spine, and also compresses your organs and limits their functions.

Because of this chair/desk paradigm, the ability of chair backs to really solve this problem is limited.

If you must sit in a chair, Galen Cranz says it’s best to ignore the chair back and sit yourself right at the edge of your seat, essentially turning the chair into a stool. Stools, says Cranz, are a good alternative to chairs, because they get your body out of the C-shape. They position the body halfway between sitting and standing.

Still, it’s not like there should be one single piece of furniture that will correct all the problems of chair sitting.

“The lounge chair is not the answer. There’s no the answer. What we need is variety,” according to Cranz. “The best posture is the next posture.”

We don’t need fewer chairs. We need more. Bring us chairs. All of the chairs.