[31] Baldwin, Social and Ethical Interpretations, p. 151; cf. pp. 150, 152.
[32] Schiller, Über die ästhetische Erziehung des Menschen, esp. Brief 15.
[33] Ibid. Brief 27, quoted in Groos, The Play of Animals, p. 2.
[34] Spencer, Principles of Psychology, vol. ii. pp. 629, 630.
[35] Spencer, “The Origin of Music,” in Mind, xv. 452, 453; reprinted in the last edition of Essays, ii. pp. 430, 431; Wallace, Darwinism, pp. 281, 284, 287, 292; Hudson, The Naturalist in La Plata, pp. 280-286.
[36] Wallaschek, “Natural Selection and Music” in International Congress of Experimental Psychology, second session, 1892, p. 74; Primitive Music, pp. 271, 272. These utterances of Wallaschek ought to be quoted as expressing his views, and not the earlier passage in Mind, 1891, p. 376, from which Groos concludes that Wallaschek agrees with Spencer. Cf. Groos, The Play of Animals, p. 6. As early as 1891, Wallaschek pointed out the importance of music and dances as preparations and not only representations of the most important actions in life. Cf. l.c. p. 74.
[37] Groos, The Play of Animals, pp. 18-24.
[38] Groos, l.c. p. 21.
[39] Groos, Die Spiele der Menschen, pp. 216-356.
[40] Guyau, Les problèmes de l’esthétique contemporaine, p. 9: “On pourrait donc, en continuant la pensée de M. Spencer, aller jusqu’à dire que l’art, cette espèce de jeu raffiné a son origine ou du moins sa première manifestation dans l’instinct de la lutte, soit contre la nature, soit contre les hommes.” Cf. also Guyau, L’art au point de vue sociologique, p. 14, where Guyau in a brilliant passage shows how an element of passionate struggle and conquest enters even in the most abstract reasoning. To be compared with the chapters of Groos on Kampfspiele.