The title translates as "actions through probability". In the case of "Pithoprakta," this relates to Jacque Bernoulli's law of large numbers which states that as the number of occurrences of a chance event increases, the more the average outcome approaches a determinate end. The piece is based on the statistical mechanics of gases,Gauss's law, or Brownian motion. Each instrument is conceived as a molecule obeying the Maxwell–Boltzmann distribution law, with Gaussian distribution of temperature fluctuation. This theory states that "the temperature of a gas derives from the independent movement of its molecules. Xenakis drew an analogy between the movement of a gas molecule through space and that of a string instrument through its pitch range. To construct the seething movement of the piece, he governed the 'molecules' according to a coherent sequence of imaginary temperatures and pressures. Brownian motion is a four-dimensional phenomenon (three-dimensions and time), and Xenakis created the score by first creating a two-dimensional graph, necessitating some simplifications. The abscissa (x) represents time at 5 cm = 26 MM, while the ordinates (y) represent pitch at 1 semitone = .25 cm. When transcribed into musical notation 5 cm = one measure. This length is subdivided into three, four, and five equal parts, allowing for fine differences in duration, but also creating a steady pulse in each instrument part, reducing the rhythm of the random walk to steady footsteps ("a situation impossible in [Each part gets nowhere, but as a whole the mass's pitch is freely modulated and its speed determined "temperature" varies.
^Ilias Chrissochoidis, Stavros Houliaras, and Christos Mitsakis, "Set theory in Xenakis' EONTA", in International Symposium Iannis Xenakis, ed. Anastasia Georgaki and Makis Solomos (Athens: The National and Kapodistrian University, 2005), 241–249.