The ideal environment in which to raise a child.

Theorem: A child, S, can survive to adulthood if and only if her immediate environment is rid of all potential dangers (sharp edges, hard surfaces, electrical outlets, tripwires, venomous snakes).

Discussion: From about the time S was starting to motivate, her mother and I realized we’d have to rein her in somehow. As Christopher is only just learning, the head bonks that come with mobility occur with terrifying regularity. S’s first major one was a tumble from a hotel bed, resulting in a resonant bonk against the leg of a chair; her mother wouldn’t let her nap all day, for fear she’d sustained a traumatic brain injury. She hadn’t.

And so we followed the Department of Homeland Security’s lead—we installed a fence in our living room. Made of flimsy wood, it arced around a cushioned playmat and our sofa, giving S enough space to roll, then crawl, then stumble without risk to life and limb. Sure there were occasional spills—when she was learning to climb off the couch, for instance—but she survived. She’s even spent whole hours in the windowsill, hiding behind the curtains in a never-ending game of peekaboo, not quite aware that only a few millimeters of glass separate her from a multi-story plunge.

Now, at a year old, S is starting to walk—and to resent her prison, which is actually larger than some New York apartments. In short, she screams if placed inside, even if one of her parents or nannies joins her to play with various squawking electronic toys. And frankly, she’s  not gonna learn to walk if she can only take a few steps at a time. Something must be done.

Proof: We will attempt to prove the theorem by contradiction—that is, by assuming its opposite, that a young child can survive a non-childproofed apartment. To that end, we have given S an open-ended furlough, removing her prison walls and exposing her to dangers such as: the kitchen! the dining table! the baseboard heaters!

Right this very minute, she’s crawling around behind my back, inspecting the carpet mat (mmm, delicious!) and dragging chairs across the floor, virtually daring them to topple onto her. I see cords she can pull, a freestanding glass-fronted medicine cabinet she can teeter, a length of coaxial cable she can fashion into a makeshift noose with her burgeoning executive functions. What will I do about these threats?

Nothing. Well, I’ll watch her closely, of course, and instruct her with a strong-voiced NO when she attempts to set foot in the kitchen or bathroom, and if she insists on doing what she’s not supposed to, I’ll pick her up and play with her in a safer corner of the apartment.

And, two days in, she’s still alive! Human babies are a surprisingly hardy lot, capable of surviving numerous head bonks (note to Chris: get the head bonk out of the way in the morning, if possible, so you can look forward to a bonk-free afternoon and evening) and much, much worse. If S can’t make it through childhood in the mostly low-rise, carnivore-free, perpetually monitored environment we’ve provided for her, then her chances as an adult can’t be very good either.

QED? Not quite, I guess, since I seem to have proved the opposite. We won’t know fully, of course, for another 17 or 18 years, but I’ll invoke here another shaky mathematical process—proof by induction. If it worked yesterday and it worked today, it’ll work tomorrow! QED!

Now, some people may think I’m a bad parent for putting little S at risk. And some people may applaud my attitude. But I think we can all agree on this: It’s a good I never became a mathematician.