includes the Clay quote above, adding, "In short, the practically cognized present is no knife-edge, but a saddle-back, with a certain breadth of its own on which we sit perched, and from which we look in two directions into time. The unit of composition of our perception of time is a duration, with a bow and a stern, as it were--a rearward- and a forward-looking end."

C. D. Broad further elaborated on the concept in Scientific Thought (1923), writing, "Every place to which an observer's body can