Our day-to-day lives constantly involve measuring size. Heading to bed we consciously (or unconsciously) determined the length of our sleep. At breakfast, we count calories (if on an appropriate diet) or at least guesstimate how much oatmeal to put in the bowl, or butter on the toast. Then there’s the time it’ll take to get to work, how long the gas will last in the vehicle, the number of items on the to-do list .