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1This study was made possible thanks to a scholarship for PhD studies granted by CAPES, Brazil, to which I am

grateful.2 Shannon (1948).3 Wiener (1948).

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7 In this article,we will be referring to pitch classes only for practicalitys sake; of course, the alphabet can contain

symbols whose nature is as varied as durations, dynamics, tone colours, articulations, etc. but also specific

behaviours, motifs, scenic gestures, instruments, and so forth. Two or more different categories of symbols can bepaired, establishing direct relationships between specific notes and instruments, for example; this possibility is

generally well addressed by matrices of transitional probabilities in stochastic music. See note 6 above.

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8

Pignatari (2002, 63).9 It is possible to argue that, since a perfect moto perpetuo is a constant repetition of symbols, Bachs Prelude would

not convey any information at all about note durations. However, while there is a constant rhythmic pattern

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i

n

ii ppH 21 log

throughout the aforementioned example until the final chord, it must be taken into account that there are other

rhythmic layers in higher structural levels along the piece, such as harmonic progressions and melodies resulting

from voice leading. In addition, no sensible performance ofBachs prelude will treat its continuous flow of chordalmotifs as having mechanically measured durations the flexibility of music expression in performance indeed adds

information to an otherwise completely redundant material.

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10 3.58, as we have already seen, is the maximum entropy possible with twelve symbols.11 Youngblood (1958, 29).12

Shannon (1948, 14).13 Cohen (1962, 140).14 Meyer (1957, 420).

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15 Hiller et al. (1966, 102).16 Meyer (1957, 412).

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1 2 3 45 6 8

Time

EntropyH

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17 Pignatari (2002, 65). The translation is mine.18 Meyer (1957, 416).

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19 Meyer (1957, 421).

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