The first has to do with the kind of situation that faced the man who knew what he “wanted to say but couldn’t express himself.” Some authorities argue that there is no difference between clear thinking and clear expression. They give no place to the “mute inglorious Milton.” They would not concede that the man groping for language had formed a definite plan in his mind, because that plan was not definite enough to be expressed. “If he has not thought in language,” they say, “he has not really thought.” Their opponents claim that a man thinks in pictures, and that he conceives his ideas as a painter imagines objects. In his mind are the outlines and colors of what he considers. There is truth in both views of the matter. But it is likely from what we know of the training of the military man that his mind works more by visualizing the troops and by conjuring up the scene than by gaining his conceptions through words. His forces are moving along roads, occupying trenches, or surging into conflict. His map is not a plane surface with names upon it, but a vision of highways, waving corps, and rolling hills. He is looking at these things without mentally describing them. For the purpose of this course, we shall take the view that there are occasions where we deduce certain results, but are unable, because of unfamiliarity with framing good sentences or because of a small vocabulary, to communicate those results or deductions in accordance with common usage. The second road can be illustrated by comparison with the first. There is a wide difference, although at first there does not appear to be, between merely stating a thing clearly and making it unmistakable. The first is but a negative approach to complete certainty of expression, but the second must be a positive one. The distinction is one more or less of attitude of mind, and although heretofore it has been overlooked as an entity in English text books and military regulations, it assuredly illustrates itself in two types of men who actually exist. The man who is content with merely making himself clear takes the attitude of, “O, well, they will get what I meant because any other interpretation is absurd or incorrect.” The man who is not content unless he makes himself unmistakable says, “I won’t let any of them have the slightest excuse for any other interpretation; when I get through there will be but _one_ interpretation and that will be _mine_.” The first one in sending a message to his commanding officer locates himself by putting in his heading, “Irrigation ditch 500 yards east of southeast corner of Catholic Church.” He notices another irrigation ditch fifty yards further to the east, but says to himself, “If my commanding officer measures the distance on the map he will know which one I mean.” The second man, upon looking about him and discovering the other ditch, does not accept the chance of letting his commanding officer confuse the two ditches by a possible difference of maps