I’ve floated a handful of times the past two years. It’s not cheap, but I try to go a few times a year. It’s still an odd experience. You sign a form saying that you aren’t on drugs or about to do them. When you get into the room, you take off all your clothes, shower, and put in ear plugs, before taking the plunge.

Eventually, that feeling of leaf-like movement abated in the first float and a stillness overtook me. I tried moving my arms around to find the maximally relaxing position. All positions were maximally relaxing. The water was heated to the human body temperature. If I concentrated on the sensations on my skin, I could still tell the difference between the water temperature and the air temperature. But sometimes even that sensation disappeared.

I normally cringe at comparisons between the human brain and computers, but some Millennial tech-tinkerers will remember that years ago you could cure a computer of some of its slowness by defragging the hard drive. Flotation feels like defragging the Human Biocomputer.

It’s not without discomforts. If you absent-mindedly attempt to scratch an itchy nose in the tank, that salty water will get in your eyes and sting like crazy. Usually a fresh-water squirt bottle is within reach to help you recover. As you dip into the tub, any cut on your skin, usually one you didn’t know you had, will be revealed to you through a very memorable lash of pain. But those sensations disappear quickly enough.