Functions of a Young Actor, Artist
A sculptor works with chisels on marble, or with fingers on clay. A painter works with colors and brushes on canvas. A violinist plays upon an instrument and strings. But the actor plays upon himself; upon his whole self; upon his body, his voice, his movements, his facial expressions, even his emotions and imagination. Subjectively he is the artist. Objectively he is the instrument.
It is not, as we have seen, a matter of ultimate importance whether the young actor feels emotion or not; his object is to induce emotion empathethically in his audience. But to do so, he must induce in them physical reactions which will be felt as emotions; and to do that he must suggest those reactions by his own physical behavior. When he does so correctly, they will feel the emotions; and so, in all probability, he will.
What really does function as a means to good acting is imagination. When a play is to be repeated through many performances, the importance of imagination grows.
It is not emotional sensibility, or temperament, or inspiration, that makes an actor; but a lively, flexible, and well-controlled imagination.