"As for characterization, I have made my people rather “characterless” for the following reasons:
The word character has come to mean many things over the course of time. Originally, it must have meant the dominant trait in the soul-complex and was confused with temperament. Later it became the middle-class expression for the automaton, one whose disposition was fixed once and for all or had adapted himself to a particular role in life. In a word, someone who had stopped growing was called a character. In contrast the person who continued to develop, the skillful navigator on the river of life, sailing not with sheets belayed, but veering before the wind to luff again, was called characterless – in a derogatory sense, of course – because he was so difficult to understand, classify, and keep track of. This bourgeois concept of the immobility of the soul was transferred to the stage, which the bourgeoisie has always dominated. There a character became a man who was ready-made; whenever he appeared, he was drunk or comical or sad. The only thing necessary to characterize him was to give him a physical defect – a clubfoot, a wooden leg, a red nose – or have him repeat an expression, such as “that was splendid” or “Barkis is willin’.” This simplified view of human character still survives in the great Moliere. Harpagon is nothing but a miser although he could have been not only a miser but an excellent fancier, or splendid father and good citizen. What is worse is that his “defect” is very advantageous to his son-in-law and daughter, who are his heirs and therefore should not criticize him, even if they have to wait a bit before climbing into bed together. Therefore, I do not believe in simple theatrical characters. And an author’s summary judgments of people – this one is stupid, that one brutal, this one jealous, that one stingy – should be challenged by naturalists, who know how rich the soul-complex is and realize that “vice” has a reverse side closely resembling virtue."
From his introduction to "Miss Julie."