where the plant is

You know how, when you live with your mother, one day you think that plant would look better next to the chair than next to the sofa, so you move it, and the moment she walks in she goes ballistic, as if you had changed the whole feel of the room? Well.

It turns out you can smell a change in arrangement at the scale of one molecule. Carvone comes in two versions built from the same atoms with the same bonds, mirror images of each other, and one smells of spearmint and the other of caraway. Nothing in the chemistry is different. The positions are, and your nose reads the positions, because the receptors it uses are shaped molecules too, and a mirrored key does not sit in the lock the same way. Who knew.

Fig. 18 · Carvone, the two ways it can be built. Same atoms, same bonds, mirror images across the red line; the left smells of spearmint, the right of caraway.

Before I get carried away: you need a great many molecules to smell anything, so this is a small difference done to a lot of things, and chemists settled it in 1971 with a panel of noses. But the question would not leave, and it sent me reading and listening for two weeks, and the reading kept handing me things that work backwards. One of them became we see in silence. Another is the eye. It is built to treat a shape and its mirror image as the same thing, which is why children write b for d and have to unlearn it to read. So a plan and its mirror look like the same room to you, and would not smell like one.

And the plant. There is, it turns out, a cell for where the plant is. In 2019 the Moser lab found neurons in the entorhinal cortex of mice that fire only when the animal is at one particular distance and direction from an object, any object, in any room. Move the object and the field moves with it. So your mother was not being dramatic. She has hardware for where the plant is relative to her, and you moved it.

Fig. 19 · Firing map of one object-vector cell, after Høydal et al. 2019. The cell fires only in the field at a fixed distance and direction from the object, in red; move the object and the field moves with it.

Which is a problem for how we draw. A building is specified as a list, every beam, every duct, every clash, tracked to the millimeter, and I have written about what that list leaves out in behavior information modeling. A list has no arrangement in it. The same four things make two different rooms depending on where they stand, and the body reads the arrangement, not the inventory. Adjacency is not access was the same idea for doors. Sensi's coupling matrix is the same idea for senses: the score lives in the relations, not the items. So what would a tool look like that scored where the plant is, relative to you, to the window, to the door you came in through? I know one person who would use it.

Fig. 20 · One room, the same four things, drawn twice: the plant beside the sofa, then beside the chair. The list is identical; the arrangement is the whole difference.