They have overcome the outer world and the social world entirely, they unfold our inner life, our mental play, with its feelings and emotions, its memories and fancies, in a material which seems exempt from the laws of the world of substance and material, tones which are fluttering and fleeting like our own mental states.

Of course, a photoplay is not a piece of music.

Its material is not sound but light.
But the photoplay is not music in the same sense in which it is not drama and not pictures.

It shares something with all of them.

It stands somewhere among and apart from them and just for this reason it is an art of a particular type which must be understood through its own conditions and for which its own esthetic rules must be traced instead of drawing them simply from the rules of the theater..