It must have been in high school biology that I learned the definition of life. Significantly, I have forgotten all the essential attributes except for one: movement. If you want to be a life form, you have to be on the move. If your ambition is to be a crystal, no sweat. You can hang out with the other crystals all you want. Which means you will get taught, as a subject, in Physics and Chemistry. Is that your crowd? You decide. Thing is, if you want to be in the biology textbooks, you’d better shake a leg. Or a pseudopod. Doesn’t matter, something has to move.

Which is the only real explanation for boarding the 8:39 morning northbound. To see my dentist, of all things. San Francisco does not exactly have an exclusive on dentistry. One can tend to teeth quite reliably in Palo Alto. But that has nothing really to do with this trip. I go to San Francisco to be in San Francisco, and to not be in Menlo Park, however briefly. And this particular day’s journey is indeed brief.

I share the wheelchair space northbound on Caltrain, which is somewhat unusual. It is one of my few windows on the larger disability world. What is life like for them, my disabled brethren? I will never know about this one, not precisely, for the young man and I exchange no more than looks. He either cannot speak or does not speak, just stares at me openly. It may be that in the brain-damaged state of cerebral palsy intellectual capacities are quite intact…but speech is difficult or impossible, facial control limited. So it’s hard to say what’s going on. My guess is this kid is all of 24 to 30 years of age. Old enough not to be a kid, that is the thing. Yet he is being taken on a kid outing.

I learn this when I am off my train, and on to the next, the Municipal Railway tram that rumbles toward my dentist’s office. The young man’s caregiver or caretaker asks him what he thinks of this train. Did he like the other one more? The young man, now on the tram, does not answer. His wrists are bent into a spastic deformity that I share, actually. He rests his chin on one hand and stares at me. He knows I am in a wheelchair. Knows I am a landsman. So we smile and nod.

At least I had the sense to board this tram. The San Francisco transit shelters sport digital signs indicating when the next bus or tram is destined to arrive. I think of my cousin Caroline in such moments, her British voice full of disbelief at my naïveté. But I can’t help it. I think the world should be an orderly and logical place, or that it is trying to be. So when the digital sign indicates that the next trams will arrive in seven minutes and thirteen minutes, respectively, I feel enormous pressure to make a choice. Because there is this tram stop in the center of King Street and the other in the center of Fourth Street…seven minutes to wait here and 13 there. But I don’t buy it. King Street is closer, whatever happens will happen. And having made this cosmic choice, damned if a tram doesn’t role in two minutes later. Which both pleases and disturbs me. For the whole system is supposed to be running on GPS data, and this just can’t be. Never mind. Soon the San Francisco waterfront is rumbling by, the great work of America’s Great Depression standing proud and steely and industrial, the Bay Bridge. And the wharves and the ships and the Bay itself.

And then we are underground where I alight at Montgomery Street. Which, I tell myself, might be a safer station for changing trams. You know, a better class of people supposedly work here. Showing how skewed and naïve my own values really are. For this is the haunt of the very people who mugged the entire nation. I avoid the narrow part of the platform. And there it is, the single car of the J Church tram. And now I am inside it and trundling toward Noe Valley. The tram ascends the steep hill along Dolores Park, reminding me in an intuitive way of why these vehicles are electric. Instant power. The driver doesn’t step on the gas, because there is no gas. He steps on a switch, essentially, and all the hill-climbing power in the world releases itself to the wheels. Releasing this tram to the world. Good place, San Francisco. We stop. Not a good sign. Passengers are not getting on or off. We have come to a halt.

There is a reason why they call it public transit. Aboard a San Francisco tram all the workings of travel reveal themselves. We are all witness to what ensues. A door is beeping. Why is it emitting this constant sound? None of us asks, but all of us wonder. Whatever is happening, our progress ceases. We must wait while the driver exits her compartment. She locks the door behind her, the key retracting on a long wound chain. I am facing forward, the problem door behind me. Who knows what she is doing? I am worrying. I am only two stops from my dentist. Close enough to roll the remaining few blocks, if necessary. Or, if possible. Which it is not. Wheelchair access to trams outside of the center of the city involves rolling onto an elevated platform with a ramp. And the latter are spaced about half a mile apart. So there is no exit until 24th St. For the first time perhaps ever aboard the Muni, I feel trapped.

But not for long. Here we are, me rolling down and off the ramp. And this is San Francisco. A brisk chill wind blowing in June. And incredibly, there is my dentist’s assistant actually waiting for me on the front steps. Can it be that Dr. Savio has been my dentist for almost 40 years? On the way out she accompanies two of her staff down the steps, one holding my crutch, the other holding me and observers that she has not seen any one human being receive such attention since the night of her prom.

All this to get my teeth cleaned, this 70 mile round trip on public transit – and worth every moment. I have many options for the journey home. And one involves the 48 bus. I ignore the digital signs in the transit shelters. There is only one way to ascertain the imminence of this or any other bus, and that is to look, which involves slightly rolling into the street, turning around and…there. Damn. Why didn’t I turn around earlier? The very bus in question has stopped at Sanchez Street, and I am already in the pedestrian crosswalk heading well away from the stop. But the bus is halted to let a passenger climb aboard. And my wheelchair is bloody fast. So, fuck it, I roll back across the intersection, present myself before the open door of the bus and stare at the driver quizzically. What else can he do? The wheelchair lift drops to the ground, I ascend, and moments later I am in the 24th Street station rolling toward the lift that will take me down to the trains. The doors close, then they open, then close again. I keep pressing the down button. We descend. Then something else happens. The doors open again. And we are back where we started.

The day has been like this. Doors. And what can one do but take a chance? I press the down button one more time. When the doors open, I am on the platform. And the subway train that connects with Caltrain is just rolling into view.