From correspondence with Klaus Kropfinger

Kropfinger: Boulez made a qualitative differentiation between Schönberg’s compositions prior to the twelve-tone period – the “expressionistic” phase – and the twelve-tone period, where he “returned” to traditional forms, among other things. Is this view (still) justified, in your opinion? Here, “qualitative” refers both to quality in the sense of conventional logical consistency (as Boulez sees/saw it) and to the quality of the compositions themselves in technical and aesthetical terms of composition, their “inner” stringency.
Is it really reasonable to dismissively call Schönberg’s use of the traditional forms of the sonata and the suite “neoclassical?” Is it not rather the case that he transferred those forms – at least partially – to a new compositional aggregate state, based on “composing with twelve tones related only to one another?”
For you, as a composer, is Schönberg still an important orientation figure – perhaps indeed because of his twelve-tone compositions, even when he proceeds from traditional form models?

Rihm: Basically, the “subdivision” of an entire oeuvre is suspicious (see the misleading talk about “the new Nono,” etc.); even in the work by a composer such as Stravinsky, who makes change into a theme – there is not a note that isn’t poised, as it were. However, I do have personal preferences, and one of them regards “Schönberg around 1910” – but of course I am aware that a creative person is not divisible. But that is something I had to learn; so I tended more and more to try and find qualities in the music which I had avoided earlier (e.g. the Wind Quintet, the Serenade, the Suite) which I had merely suspected; suddenly I was seized by the same heat, the same freedom and aplomb – I found the same concision and voluptuousness, the same wealth of correlations freely handling the correlated areas as I thought I had recognized. At the same time, a new dimension of sonic keenness, an enormous cutting-metallic espressivo had joined the mix, an espressivo which could counterbalance the thoroughly tangible loss of warmth (i.e. suppleness, too) as an experience. The “formal straits” seem to me typical of the time and definitely originating in uncertainty. Certainly Schönberg wanted to participate in an international artistic dialog – and international Esperanto was the neo-classical inflection at that time – and he indeed knew how to attract an urban, metropolitan atmosphere with those crumbling, juxtaposed compilations of form – the constructions which relived the growth forms in that stylistic phase and which could definitely be read as psychological armoring of or through “inexorability” and “stringency;” back then, those constructed form components (for they no longer primarily evoke association with the organic) were certainly more modern, less comparable with Jugendstil, more cellular (thus also related to the organic), more atomic, more “scholarly” in the tone of the times, less “merely” artistic, more “objective.”
That distances them from us, and we must take the first step; the earlier works are more proximate to us, they do not seem so “archaic” because, when they were created, they emerged from Schönberg’s inner monolog, unrelated and strange. The later works (with which Boulez is concerned) confront us as an “expression of their time” – and at once they seem narrower, more reduced, “less” than the ill-timed expressionistic pieces. So it might be that way “as well;” whether it is so, in fact, I do not know. What is important to me is that they possess stringency in the legible sense almost more than the early works – one could almost say “They are composed ‘better.’” But perhaps the earlier ones are indeed incomparable. Now that I also love the ones I formerly did not love, I find the qualities in one of them are present in the others.
I think Schönberg used the forms like a writing-cushion, an underlay to write on. Entirely as a means, never as an end. A mode of transportation, perhaps (and yet – as I suggested earlier – the international dialog, Paris, Cubism, Picasso, Stravinsky – Berlin, too…). Of course he did not want to re-introduce the “old forms;” he had discussions with them – more intimately, perhaps, than Stravinsky, who “merely” assembled them, and did not actually converse with them.
Besides, just as the texts in the expressionistic phase often functioned as a simple guarantee for any kind of procedure, the old forms (as “texts made of music”) could well have been guarantees of advancement in the “twelve-tone phase,” viz. the advancement of the combinatorial fields. The combinatorial fields needed to be moved, of course; they did not arise spontaneously as an energetic flux (and this is my critical point of this – and every – systematic formulation; its interruption of the flux, of the self-generation of the gestalt configuration, per se and precisely when the system was developed for that reason – in order to guarantee the gestalt configuration); I feel that these combinatorial figure-fields tend toward the static, toward – today we would say, “minimalist” configuration […]
The forms which Schönberg applied to the procedure, the targeted progress, are foremost  not dynamic processes but, for their part, are “static images,” those of a constant procedural modus, of a sustained character. Not recurring so often with the sonata – and there, too, I find a renunciation of dualistic-dialectical gestalts and gestalt-fields, in favor of a uniformly characterizing, seamlessly grouted wall (incomparable in the Third Quartet, which I did not understand, did not want to understand, for a long time; I hated the “Alberti bass” accompaniment at the beginning in my youth especially, against the background of Schönberg’s Hauff reference – today I see it somewhat more differently, even allowing myself to see in the compulsive procedures the nailing which the captain – Schönberg? – hammers into the mast and which hampers his own steering). Well, Schönberg is not Hauer, and that is why, with him, “compulsion” is always something hot, lively, erotic (even if palpably not lived out on occasion) – at all events, nothing which behaves merely tropically on paper.
As a totality of apparition, as a contradictory spirit and generative energy, Schönberg for me is a man of enormous energy, indeed the battery, the payload on which recharging becomes imperative. (As much as I love them, I experience Webern and Berg as being very dependent on that recharging). Schönberg remains the primary source. With him, nothing rounds off to the classic model, and when he speaks of “system,” it sounds as though he is inferring the opposite. With him, density is nothing fabricated; it is the instance of what is said, what is composed. And when he sought other expressions in biographical phases, found them, lost them and found them again, as a creative potency he is unalike far wider in his extent than one who seeks to expand his accomplishments. Schönberg is a wastrel, an excessively rich profligate. But to be under his spell does not mean to spetrify – it means to be set into motion and to remain that way, in-cess-ant-ly.
Now I go to orchestra concerts to hear the figures, doubles and prisms by Boulez, in which Schönberg is anything but “mort”. . . indeed, that is where he comes to life again – if he ever was dead. I also believe that, when he dies, every artist is initially dead in a productive way. His commandments (either prepared by himself or decreed by exegetes) become extinct at once; everything which may have been designed intending toward expansion, securing livelihood, even afterlife, and whatever served merely to assure an undeserved canopy over weak situations, everything secondary which has been around him, is exposed to the greatest erosion after his death.
And that is good, because thus the primary apparition, the substance, the essence, will become visible undistorted and, with time, recognizable as “immortal.” Playing one’s part against one’s opponent is the price for contemporaneity. Schönberg and Stravinsky are alive today. Mozart is in the process of being murdered again, but don’t worry; a year from now he will sit down again with Stravinsky and Schönberg, who will joyfully greet him and ask him where he’s been hiding the whole time […].

Ausgesprochen. Writings and Conversations. Volume I. Edited by Ulrich Mosch.
Winterthur 1997 (Publications of the Paul Sacher Foundation, 6/1), 273–275