Christopher likes timetables because he likes knowing what will happen when. He provides his timetable for a normal day at his father’s house, which has every activity mapped out to the minute. He makes other timetables for the weekends, and he doesn’t like going on vacation because people don’t use timetables then. For Christopher, a timetable is like a map of time, except on a map of objects the objects are still there even if the map isn’t; whereas time seems to disappear if he doesn’t have a map of it. Time changes depending on how other things change—for example, it works differently if you’re traveling at the speed of light. Because nothing travels faster than light, humans can’t know about many things that happen in the universe. Christopher sees time as a puzzle, and timetables keep him from getting lost in it.
Christopher has a very visual sense of time, starting with the fact that he thinks of a timetable as a map. Most people don’t think about time in this much detail, but Christopher’s view of it makes time seem particularly slippery. As a result, he feels the need to pin it down by making a timetable so that he knows that time will continue to exist in the measured way that he wants it to. Essentially, he asserts that time is subjective, not only because of human perspective but also because of scientific principles. This attitude also explains his need to constantly wear a watch.