It is all right to say exactly what you think if you have learned to think exactly.

Marcelene Cox (1900–1998) American writer, columnist, aphorist

“Ask Any Woman” column, Ladies’ Home Journal (1945-11)
    (Source)

Cox provided a variant of this aphorism in the 1959-01 issue of LHJ: "Anyone has the right to say what he thinks, if he thinks."