From the beginning I could not believe that the efficient market hypothesis was dependent on a pure Brownian motion white noise or any truly random random walk. Place a minuscule colloidal molecule on a horizontal table that covers unlimited acres. Bombard it from every direction with thousands of minute atoms; and then if you wait long enough that original molecule can have traveled a billion miles in one direction. That's truly a random Bachelier-Einstein walk, but not my notion of economic fluctuations.
New millennium - An Enjoyable Life Puzzling Over Modern Finance Theory, 2009