On clear nights, for part of the month, I can see the Moon out my front window, up above the tops of the row houses across the street. When the Moon is full, that means the Sun is almost directly behind and below the Earth, eight light-seconds away (around 8 million miles). The Moon is small in comparison to the Earth, and is only about 240,000 miles away, about 30 times the Earth’s diameter. The Sun is vast compared to the Earth.

That is to say, I’m teensy. But the Moon, Earth, and Sun are also teensy in comparison to the Universe. The closest star to us (Proxima Centauri) is about 4 1/2 light years away, and unlike the Moon, I can’t see it, because it mostly radiates in the infrared. I won’t tell you how many miles away that is, because it stops having any meaning. It’s so far that we will never get there, no matter what the billionaires or the movies tell you.

That doesn’t stop me from writing books set on other worlds. Reality is all very well, but most of what we deal with in everyday life is imaginary. I have never been to the Moon, will never go to the Sun, and am taking on faith all the facts I just expressed. I have some faith in certain kinds of expertise, because it’s necessary.

I didn’t start out to write about space; I was actually thinking about the calendar. I just looked at December on my computer, and on my computer December looks like a grid. I can infer from that tidy little array of numbers that there are two weeks or so until the winter solstice, less than three until Christmas.

Also, it’s Monday.

But none of that is real. Months, weeks, days of the week, times of the clock, all imaginary and inventive human ways of thinking about the past, the present, and the future. Highly arbitrary ways, in fact; names, numbers, cyclical patterns, all invented by human beings and only loosely connected to the movements of local bodies in space. Time may be a dimension, like distance, but what the hell do we know? Mostly we make elaborate inferences, some more reliable than others.

Monday in particular is not real, especially since I retired. More and more, I grow unmoored from the days of the week, because though I lived in that framework for many decades, I moved steadily out of the framework some time in the last three years.

Speaking of being unmoored, I just found out that Dame Judi Dench is 91. She can’t see very well any more, because of macular degeneration, and she often forgets what she is doing tomorrow. Of course, Judi Dench is also not real. Nor is our current President. In fact, he is even more improbable than an actress I have seen only on film or on Reddit, a site that is packed with staged, artificially generated, or recycled videos and photographs. In certain cases Reddit is more trustworthy than the news, at least if I already know what kinds of statements I can sort of trust, but I always verify.

None of this is important. I am sitting at my desk, with my fingers on a keyboard, and the forced-air heater just stopped running finally. The house is ticking gently, as it often does. The cat has his front paw over his nose, because he has been fed. This is it: the cat, the house, the air, the fingers. It’s all I really have, the only reality, and even that is provisional.

I am not going to go all philosophical at the moment; it’s just that every day, in my journal, one of the things I write to remind myself not to take things too seriously is, “This is it.” Right here, right now, it’s the only reality I have, and when I see the Moon out my window it is probably a solid body orbiting the Earth, but it is definitely a lovely white sphere in a luminous sky.

Also, I have to go to the grocery store to get some seltzer today, because tomorrow is Tuesday and we’re celebrating the last class in Intermediate French. I signed up to take the class next term, too, assuming next term is an actual thing. You never know