Argument from silence illustrated: Josephus omits his own capture by Romans from his autobiography; Grant's memoirs never mention the Emancipation Proclamation

Josephus does not mention his capture by the Romans in his autobiography (though he does in Jewish War). Ulysses S. Grant wrote two volumes of Civil War memoirs without once mentioning the Emancipation Proclamation. Absence of mention does not imply ignorance or non-occurrence.