Space and Time Beyond Common Sense

From the opening pages

Everyone knows what space and time are. This is fortunate, because otherwise leaving the house would require a degree in philosophy. Space is where things are. Time is when things happen. There: two definitions, ten words, civilization saved. We may now return to genuinely difficult matters, such as changing the settings on a printer. The trouble begins when someone asks what “where,” “things,” “when,” and “happen” are doing in those definitions.

Suppose your keys are on the kitchen table. If someone asks where they are, you say, “On the table.” If pressed, the table is in the kitchen, the kitchen is in the house, the house is on a street, and the street is in a city. Ordinary conversation works perfectly. At no point are you required to explain what location itself consists in. We simply answer one question of place by giving another place. The same economy applies to time. When is the meeting? At three. When is three? This afternoon. When is that? Friday. Practical life needs coordination, not a theory. Most of us can reach a dentist’s appointment without first solving the nature of temporal reality, which is fortunate for dentistry.

This is the first trap: familiarity feels like understanding. A child can catch a ball without knowing mechanics. A cat can judge the distance to a chair without producing a theory of geometry. A commuter can complain that a train is twelve minutes late without settling any philosophical question about time. We navigate, compare, estimate, remember, anticipate, arrange, and measure. Because these activities usually succeed, the concepts involved seem transparent. The more constantly we use them, the less often we notice that we have not explained them.