Dear Jonas,

Pumpkins are in season, and I brought one home for you. This means Halloween is coming and the weather has turned. The warm, moist air you’ve gotten used to is now crisp and chilly. You stick your tongue out to test the difference, and you seem to approve. The mittens Laura knitted for you are on your little hands 24 hours a day, but you kick off your tiny socks after a few minutes. Today was your grandpa’s—my father’s—birthday, and when I was little he and I began a tradition that released in me a sort of immediate nostalgia. It has to do with the pumpkins. And the air. And cacti.

I suppose I should tell you about nostalgia first. The Greek root words for nostalgia are ‘returning home’ and ‘pain’: homesickness. In its early days, nostalgia was diagnosed as a physical illness. It is now understood as a psychic phenomenon similar to melancholy, which I will tell you about later. There are other generative types of nostalgia that things such as theme parks and political campaigns create, but I want to tell you about something quite different—something soft and private that teaches you how to coddle your past.

I’m going to guess that I was 3 years old when I had an experience that would later repeat itself countless times as nostalgia. My Dad picked me up from preschool at Peniel Baptist Academy in his sky blue Chevy pick-up truck. That truck had a CB that worked and a cigarette lighter we weren’t allowed to play with. Dad still had a long blonde ponytail and his beard was still red. On this particular day, once I was next to him in the bouncy cab of the Chevy, he explained that we were going to pick out a pumpkin on our way home. I actually don’t remember where we went and if it was a big patch of pumpkins or if we just went to the produce department at Publix. I do remember him explaining that we had to decide if we wanted a large or small, round or skinny one. Then we could examine all of the pumpkins with that shape until we found one that was just right. Importantly, the whole pumpkin did not have to be perfect. What it really needed was a nice smooth side that would serve as its face. Later we would decide what sort of a face (scary, silly, teeth or no teeth) to carve. When we were finished, our pumpkin would be lit from the inside with a little candle, and its transformation into a jack-o-lantern would be complete.

I am telling you how I remember this day, which might actually be a composite of several years of pumpkin carving with my father. The association of my Dad with pumpkins, and with the first cool weather of the year, and with our daily ritual of him picking me up from preschool, these are the impressions that come back to me. I also remember the first time I felt a memory bristle like this with loss and pleasure at the same time. The following summer, Dad and I were walking through the yard looking for vestigial cacti. Since we’d moved in two years earlier, he had been digging them up at the root one-by-one. On this particular day we were hunting for residual succulent mines, and talking about time. For some reason I wanted to know which month was my father’s favorite. He chose October for its weather and because of his birthday. When he said this, our previous October and the pumpkin came back to me. It felt like a regular memory, but it made my stomach tingle, too. The memory turned visceral, and the rest of my day became a comparison between today and last October. I can’t tell you if we found any cactus plants that day, but I felt as if I’d stepped on one anyway. Nostalgia is like that: you can never completely uproot it, and it will pierce you when you aren’t paying attention. You are better off just letting it grow.

In Japanese, “natsukashii,” condenses the term into an emotion. Someday you might find that a cat sinking as he tries to walk through snow or a chuckling diesel engine or a bush of white azaleas in first bloom triggers a memory so sharp that it derails your whole week, or ruins the new relationship to which you’ve been trying to devote yourself, or makes you want to call me, and when it does, you can. Just say, “Natsukashii, ne.” I’ll know what you mean.