Tonality of the Soul

The tonality of the soul (tonalité de l'âme) is Pierre Klossowski's term — retained by Daniel W. Smith as "tonality" because the usage "is as unusual in French as it is in English" (Translator's Preface §3) — for the fluctuating intensities of the soul, "their diverse tones, timbres and amplitudes." In *Nietzsche and the Vicious Circle*, "the tonality of the soul is a fluctuation of intensity" (Ch. 3), and the high tonality (hohe Stimmung; Nietzsche's höchste Gefühl, highest feeling) is the affective pitch in which the Eternal Return was revealed at Sils-Maria. The decisive thesis is that "intensity is the soul of the Eternal Return": the Return is not a cosmological proposition but the self-designation of an intensity that, at its peak, empties the sign of the self. Klossowski's tonalité/Stimmung is the affective-intensive register of mood, and must be distinguished from the Heideggerian ontological-disclosive Stimmung the wiki tracks elsewhere (see the false-friend caution below).

Key Points

Tonality = fluctuation of intensity: "The tonality of the soul is a fluctuation of intensity. In order for it to be communicable, the intensity must take itself as an object, and thus turn back on itself" (Ch. 3). The soul's tonality is impulsive intensity, not a psychological "mood" laid over thought.
Intensity becomes a sign by self-repetition: "By turning back on itself, by repeating and, as it were, imitating itself, it becomes a sign" (Ch. 3). A sign "is first of all the trace of a fluctuation of intensity."
Intensity has no meaning beyond being intensity: "Intensity never has any meaning other than that of being an intensity" (Ch. 3) — yet it is the "agent of meaning." Every signification "remains a function of Chaos, out of which meaning is generated."
The hohe Stimmung is the condition of the Eternal Return: "The hohe Stimmung, the high tonality of my soul, was required in order for me to know and feel the necessity that all things return" (Ch. 3). The Return is "the supreme thought" because it is "the supreme feeling."
The high tonality empties the self-sign: at the peak intensity, the sign of the self "is devoid of intensity, and... all significations of this self are emptied — at the lowest point" (Ch. 5). The coincidence of highest and lowest is the vertigo of the Circle.
So many high tonalities, so many gods: "When these Stimmungen blossom into fabulous physiognomies... the universe appears as a dance of the gods... the highest of which came to him under the sign of the Circulus vitiosus deus" (Ch. 3).

Details

Why intensity is "the soul of the Eternal Return"

The Return, for Klossowski, says nothing in itself "except that existence has meaning only in being existence, and that signification is nothing but an intensity. This is why the intensity is revealed in a high tonality of the soul" (Ch. 3). Because the self is only the sign in the code corresponding to a degree of intensity, a sufficiently high tonality liberates "the fluctuations that were signifying it as a self," so that "it is the past that rings out anew in its present." The Return is the form this liberation takes — "all things acquire signification only through the intensity of the circle" (Ch. 9).

The wave

Klossowski draws out Nietzsche's recurrent figure of the sea-wave: intensity is "a wave [Onde] in the concrete sense," and "like the figures that rise to the crest of a wave, leaving behind them only foamy froth — such are the designations through which the intensity signifies itself. And this is what we call thought" (Ch. 3). Thought is the froth of an intensive fluctuation that "can never absolutely disengage itself from the moving chasms it masks."

False-friend caution: Klossowski's Stimmung ≠ Heidegger's Stimmung

Both Klossowski and Heidegger use Stimmung, and both refuse to reduce it to "psychology" — but the registers diverge:

Heideggerian stimmung (the wiki's existing page) is ontological-disclosive: the Ge-stimmtheit under which beings-as-a-whole disclose themselves; the ἀρχή of philosophy; Rausch as the aesthetic Grundstimmung; the epochal attunement of an age. It is a structure of Dasein's openness to Being.
Klossowski's tonalité / hohe Stimmung is affective-intensive: the fluctuation of impulsive intensity that designates itself as a sign. It is a structure of the semiotic-of-impulses, not of the disclosure of Being.

The shared anti-psychologism is real, and both can be called "conditions of intelligibility" of what appears — but Klossowski's tonality conditions the self-designation of intensity, whereas Heidegger's Stimmung conditions the disclosure of beings. Treat the relation as a contrast, not an identity; a typed "contrasts with" link, not a "shares mechanism with."

Connections

is the affective-intensive register of semiotic-of-impulses — tonality is the fluctuation of impulsive intensity
is the condition of eternal-recurrence — "intensity is the soul of the Eternal Return"; the hohe Stimmung was "required" for the revelation
empties the sign of the-agent-suppot — at peak intensity the self-sign is devoid of intensity
culminates in circulus-vitiosus-deus — the highest tonality "came to him under the sign of the Circulus vitiosus deus"
contrasts with stimmung — same German word, different register: Klossowski's affective-intensive intensity vs. Heidegger's ontological-disclosive attunement (false-friend caution)
reconstituted by the simulacrum — art "reconstitutes... the intensities of the impulses"

Open Questions

Is Klossowski's "intensity" a quantitative magnitude (as the energy-analogy in Ch. 5 suggests) or a qualitative tonality? He oscillates — "quantity is quality itself" — and the ambiguity is load-bearing.
Could the Klossowski/Heidegger Stimmung relation be a latent-adjacent cross-tradition cousinhood rather than a mere contrast? Both refuse psychologism and both condition intelligibility; the registral divergence (affective-intensive vs. ontological-disclosive) is exactly the kind of axis-(iii) difference the wiki's weave Pass 3 vocabulary tracks. Flagged for a possible weave scan, not asserted here.

Sources

klossowski-1969-nietzsche-vicious-circle — Translator's Preface §3 (tonality defined; the apophatic-mystical borrowing); Ch. 3 ("Forgetting and Anamnesis": tonality as fluctuation of intensity; intensity becoming a sign; the hohe Stimmung and the Return; the wave; so many tonalities, so many gods); Ch. 5 (the high/low tonality coincidence; the emptying of the self-sign)