ABSTRACT
We all have an intuitive sense of what space is and what time is. Space is something in which ‘bodies move’ and time is something that sequences these movements. To make these notions quantitative we need to adopt a procedure to assign numbers to ‘locations’ and put time stamps on events. It is in terms of these assignments or coordinates that we make the space time explicit and it is this explicit model that is used in physics. All the tourist maps we use and the scheduling we struggle to achieve are based on precisely such ‘made explicit’ space and time. There is no unique way to assign coordinates and time stamps. Herein enters an observer (= adopted procedure).
