Genuine doubt is a state of mind so distressing that many persons cannot support it long. If I may be allowed to use the word “Habit” to denote any state of mind by virtue of which a person would, under definite circumstances, — mostly, if not invariably, consisting in his experiencing conscious experience of some kind, — either think, or act, or feel in a definite way, […] then doubt may be defined as the state of mind in which one is stimulated to incompossible intellectuals assents. This is positive doubt, — an irritation not finding its immediate appeasement and therefore resulting (since it is a mental irritation) in conflicting inchoative judgments accompanied with pain. A negative doubt is the mere absence of a state of Belief, that is to say, of a habit of determinate expectation under definite circumstances.