A black box originally meant a coffin. A light box was a bed for waking up in or a garden full of unmarked snow. The black box would be opened & its contents subjected to ritual examination — a kind of haruspicy to divine the past. We would stand around making small talk in the presence of the dead & see what made their eyelids twitch. The light box couldn’t be opened because on closer inspection, it turned out to include everything. To examine its contents, you started with yourself.