Let us believe that it is possible to profit through economic changes by following today's trend, as it is revealed statistically day-by-day, week-by-week, or month-by-month. In doing this we should entertain no preconceived notions as to whether business is going to boom or bust, or whether the Dow-Jones Industrial Average is going to 500 or 50 [This was published in 1956]. We will merely chart our course and steer our ship in the direction of the prevailing wind. When the economic weather changes, we will change our course with it and will not try to forecast the future time or place at which the wind will change.
-- William Dunnigan