Confounding the Unfamiliar with the Improbable

Page 419 of Nate Silver's 2012 book "The Signal and the Noise" contains this quote from Thomas Schelling's foreword to Roberta Wohlstetter's 1962 "Pearl Harbor: Warning and Decision":

• There is a tendency on our planning to confuse the unfamiliar with the improbable. The contingency we have not considered seriously looks strange; what looks strange is thought improbable; what is improbably need not be considered seriously.