Who Needs Convertible Slippers?

Designers obsess over “revolutionizing” products, but not everything has to be reinvented.

The author's larvik dark and light grey Mahabis classic slippers (Ian Bogost)
“Hang on, I just have to put my soles on,” I call after the kids, who are racing out the door for a trip to the market. The soles in question are two dove-gray, rubber flaps that snap to the bottoms of my slippers, which I have just imported from London. A slipper-transformer that will transition me from scruffy writer-dad to euro-sleek snacks prospector in mere moments. I am excited. I am embracing design.
I have been for two weeks or more, in fact, ever since I ordered the $89 Mahabis convertible slipper—footgear that I had seen advertised so extensively online, I finally had to click. Its webpage features a young, beautiful blonde couple. Him: sporting a man-bun, his beard both wispy and full all at once. Her: mostly Cupid’s bow, likely to be “picking at her eggs” in a magazine profile. Both don their woolen Mahabis. Typeset in front of them: “reinventing the slipper.”

Reinvention is a fundamentally modernist drive. One of its sources is a famous aphorism of the 19th-century American architect and “father of skyscrapers,” Louis Sullivan: “Form follows function.”
First advanced in 1896, Sullivan’s idea is profoundly conservative, as this fuller citation from his essay “The Tall Office Building Artistically Considered” shows:

Whether it be the sweeping eagle in his flight, or the open apple-blossom, the toiling work-horse, the blithe swan, the branching oak, the winding stream at its base, the drifting clouds, over all the coursing sun, form ever follows function.

Sullivan is saying that once something’s purpose is established, there is no need to alter its shape absent new external factors. “Where function does not change, form does not change.” It’s not just that the design of an object should emanate from what that object does, but also that changes in purpose are relatively rare.
As modernism became synonymous with the minimalism of Bauhaus and Functionalism throughout in the 20th century, ornament and tradition gave way to simplicity and extraction. The eventual result was the fusion of art, craft, design, and technology that even slippers take as a given today. For designers like Ludwig Mies van der Rohe, art became an expression of structure, order, and clarity in life. The Braun industrial designer Dieter Rams evolved that clarity into 10 now-famous design principles, including innovation, utility, and longevity. Rams has had enormous impact on populist neo-minimalism in consumer goods—including Apple’s famously minimalist products and their subsequent influences, among them Mahabis slippers.
The problem: simplicity and innovation unmoored from function. Soon enough, for example, the iPhone might not have a headphone jack. Not because form must follow function, but because Apple’s product roadmap demands it—better audio, thinner phones, proprietary accessories, closing the analog loophole. Innovation also changes purposes. Removing the eighth-of-an-inch jack from the smartphone changes function by changing form. Increasingly, innovation’s benefits are unclear. Sometimes it serves secret goals, as in Apple’s case. Other times, innovation becomes the goal, no matter its contribution to form or function.
Mahabis’s “revolutionary slippers” offer a view onto the absurdity of extreme innovation. The detachable sole is not a senseless idea. As work, home, and leisure blend into a singular murk, the sharp line between work and home apparel has blurred. Perhaps shoes should adapt accordingly.
In response, the Mahabis’s thermoplastic polyurethane (TPU) sole “flicks on and clips-down in seconds” on the wool-clad main slipper. It offers sufficient grip for wet surfaces or driving, allowing seamless, Jetsons transitions between home-office thinkpiece writing and quick jaunts to the foodie court boulangerie.
Or it would, anyway, if the “effortlessly adaptable” sole would just adapt, already. I’d imagined the slipper-to-sole deployment process to work like deft machinery. Like a Gundam suit. Two steps, upright, woolen foot would click into rubber sole, and off I would go, rethinking comfort and style. In reality, it’s more like applying a live cephalopod to the foot. It’s nigh impossible while standing.
Later, after the soles are doffed, another problem: A rear snap secures the sole to the shoe. If it doesn’t get closed again after their removal, its stud grinds crisply against the socket. It mimics the sound of crunching Cheerios underfoot.
These and other flaws are not fatal to the footwear. It’s a nice slipper that operates about as well as any 3-in-1 product you might see on late-night television. But mostly, the slipper’s function doesn’t really matter. In its place: the experience of anticipating, acquiring, and possessing a supposedly-designed object—even if at the expense of actually using it.
In particular, Mahabis liberally slathers on “user experience design” (UX) a holistic approach to a user’s interaction with a product. Common examples include shipping consumer electronics with pre-charged batteries, or designing product packaging so it’s easy and pleasurable to open.
UX was birthed for computation, but by the aughts it had taken on largely affective connotations. By then, computing gadgets had become widely admired experiential goods. Mahabis is one of many commodity manufacturers that present their ordinary wares as if they were complex, high-tech goods.
Here’s how it goes down. A few days after ordering, I receive an email from the company’s “journal.” It invites me to review the Mahabis guide to friluftsliv, the Norwegian concept of “free air life.” A week later, a gleeful proclamation hits my inbox, “Woohoo! Your Mahabis went out for delivery!” When the package hits my doorstep, it looks like a MacBook. Literally: a plain-white, shrink-wrapped box the size of a laptop package. Cardboard moldings nestle the slippers inside. The soles come in a separate heavy-duty, textured plastic zip-case. It’s so nice that I still haven’t thrown it away.
Inside the box, a notice, printed in lower-case casual: “downtime. redesigned.” It promises that my new slippers will offer a “search for adventure” and a communion with “perfection in the mundane.
The notice that came with the author’s slippers (Ian Bogost).
Suddenly, I am not even sure what slippers are, even.

When lifestyle products have adopted the design sensibilities of technology, innovation and simplicity are supposed to blend, offering access to both efficiency and meaning all at once. But the result shares more in common with associative marketing—connecting products to lifestyle aspirations—than it does with functionalist design. Nike makes you believe in your capacity to be athletic. Jeep affirms your sense of hypothetical outdoorsiness. Whether you ever visit the cross-fit parlor in your trainers or take your SUV off-road doesn’t matter. The products rely on the idea of doing so as sufficient.
Today, revolution is the ultimate branding exercise. The operation of a product—whether it’s an automobile, a smartphone, an app, or a slipper—is less important than the depth of its commitment to the rhetoric of innovation. And to be fair, Mahabis is hardly alone in such boasts. Rainshader crows about its “revolutionary umbrellas.” A new AI lunch robot called Forkable promises to “reinvent lunch.” What does it mean to reinvent slippers or lunch? It doesn’t matter. All that matters is that the reinvention is promised and packaged, like a MacBook in a shiny box.
The slippers are fine. Pretty comfortable. I suspect I will ultimately forego the finicky sole-swapping routine. Likewise, I will not expect them to facilitate my commitment to friluftsliv (or work-life balance, or slow living). Louis Sullivan had it right. Like the high-rise or the Gothic cathedral, the function of slippers is well established and unchanged.
Innovation has become so diluted that true reinvention must reverse it. The true reinvention of slippers—or of anything—must involve the humility of acknowledging that most things precede us. Perhaps the virtue in design needed most today isn’t making something old new again, nor even in making something complex simple. Rather, it's in embracing the traditions that make things what they already are, instead of assuming that what they might become is most important.