Conscientiousness is primarily the virtue of intelligence in regard to conduct. That is to say, it is the formed habit of bringing intelligence to bear upon the analysis of moral relations--the habit of considering what ought to be done. It is based upon the recognition of the idea first distinctly formulated by Socrates--that "an unexamined life is not one that should be led by man". It is the outgrowth of the customary morality embodied in usages, codes and social institutions, but it is an advance upon custom, because it requires a meaning and a reason. It is the mark of a "character which will not be satisfied without understanding the law that it obeys; without knowing what the good is, for which the demand has hitherto been blindly at work" (Green, Op. cit., p. 270). Conscientiousness, then, is reflective intelligence grown into character. It involves a greater and wider recognition of obligation in general, and a larger and more stable emotional response to everything that presents itself as duty; as well as the habit of deliberate consideration of the moral situation and of the acts demanded by it.
Conscientiousness is an analysis of the conditions under which conduct takes place, and of the action that will meet these conditions; it is a thoroughly _objective_ analysis. What is sometimes termed conscientiousness is merely the habit of analyzing internal moods and sentiments; of prying into 'motives' in that sense of motive which identifies it not with the end of action, but with some subjective state of emotion. Thus considered, conscientiousness is morbid. We are sometimes warned against _over_-conscientiousness. But such conscientiousness means simply over-regard of one's private self; keeping an eye upon the effect of conduct on one's internal state, rather than upon conduct itself. Over-conscientiousness is as impossible as over-intelligence, since it is simply the application of intelligence to conduct. It is as little morbid and introspective as is the analysis of any fact in nature. Another notion which is sometimes thought to be bound up with that of conscience, also has nothing to do with it; namely, the notion of a precision and coldness opposed to all large spontaneity and broad sympathy in conduct. The reflective man of narrow insight and cramped conduct is often called the conscientious man and opposed to the man of generous impulses. This comes from identifying conscience with a ready-made code of rules, and its action with the application of some such fixed code to all acts as they come up. It is evident, on the contrary, that such a habit is opposed to conscience. Conscience means the consideration of each case _in itself_; measuring it not by any outside code, but in the existing moral situation.