The camera assumes the task of removing every superfluity and directing the attention of the spectator in such a way that he shall see only that which is significant…
The film spares this work of stopping and downward-gliding. Thus the appearance assembled from a series of significant details is stronger in force of expression from the screen than is the appearance in actuality.
Editing is not merely a method of the junction of separate scenes or pieces, but it is a method that controls the ‘psychological guidance’ of the spectator. The guidance of the spectator to different elements of the developing action in succession is, in general, characteristic of the film. It is its basic method.
– Vsevolod Pudovkin, quoted in Eye of the Century, Francesco Cassetti