It was the sheer magnitude of Beethoven’s achievement that posed a central problem to his successors. In his hands the symphony became the most dynamic and concentrated of all musical genres. The very different social order that emerged in the wake of the Napoleonic wars opened new expressive horizons while the development of the orchestra in the nineteenth and twentieth centuries ensured it the most varied and sophisticated of tonal palettes. Less than a decade after the Ninth Symphony was first heard, the Symphonie fantastique burst on to the world, and it was followed before the end of the century by the mammoth canvases of Bruckner’s Eighth Symphony and Mahler’s Second, inconceivable without Beethoven’s Ninth Symphony. So, too, is Wagner, who abandoned the sonata time-scale, to create his own vast but essentially symphonic structures and proportions.

Any great symphony launches a listener on a mighty voyage; it conveys its illusion of movement by a complex of factors. Its composer’s ability to generate motivic transformation and growth from a seminal group of ideas is fundamental. His skill lies in harnessing the tension generated between related key centres, however nebulous they may have become in our own times, for it is the rate of tonal change which serves to convey movement. Its organic cohesion and sense of inevitability must be such that the listener cannot conceive of the musical journey on which he is embarked taking any other course. One cannot imagine the Fourth Symphony of Brahms or the Seventh of Sibelius proceeding in any other way.

In the greatest of symphonies, form and substance are indivisible. Sibelius once spoke of musical ideas themselves determining form, and compared a symphony’s development to a river. The movement of the water determines the shape of the river bed, and in his analogy the river-water represents the flow of the musical ideas, and the river-bed that they form is the symphonic structure. Schoenberg put it differently but no less trenchantly: “form means that a piece of music is organized, that it consists of elements functioning like those of a living organism.” At the same time it must convey the impression, as he puts it, that “the composer conceives an entire composition as a spontaneous vision.” The two are not incompatible, for conception and realization are different process, but the impression made on the listener is that the composer has caught a glimpse of something that has been going on all the time in some other world that he has stretched out and captured. A letter Sibelius wrote in the autumn of 1914 puts it perfectly: “God opens his door for a movement, and his orchestra is playing the Fifth Symphony.”

Robert Layton
From: A Guide to the Symphony