The science of life has nowadays to a certain extent become a crossroad, in which the contemporary intellectual developments converge. The biological theories have acquired a tremendous ideological [weltanschauliche], yes even public and political significance... The condition of biology, problematic in many respects, has led to the situation that the philosophies of life were until now by no means satisfactory from the scientific as much as the practical point of view; we see all the more clearly the importance of the theoretical clarification of biology.

Bertalanffy (1930, p. 4–5) as cited in: M. Drack, W. Apfalter, D. Pouvreau (2007) "On the making of a system theory of life: Paul A Weiss and Ludwig von Bertalanffy's conceptual connection". in: Q Rev Biol. 2007 December; 82(4): 349–373.

ON THE MAKING OF A SYSTEM THEORY OF LIFE: PAUL A WEISS AND LUDWIG VON BERTALANFFY'S CONCEPTUAL CONNECTION[ncbi.nlm.nih.gov]