 Two principal factors appear to have been responsible for the failure to take organization seriously in biology. First there is the vague belief that only atoms and molecules are ‘real’, and secondly the incautious use of the notion of chemical composition. Also the biological entities are found to be composite in the same sense, and moreover, some of the relata in the relation of composition in the physico-chemical objects are also relata in the biological objects. But the analysis of organisms as carried out by biologists reveal other relata in mutual relation of composition in a different sense, i.e., not in chemical composition, e.g., the organism is analysable into organ-systems, organs, tissues, cells and cell-parts. There is a hierarchy of composing parts or relata in a hierarchy of organizing relations. These relations and relata can only be studied at their own levels (cf. the quartz crystal) and not simply in terms of the lower levels. (Woodger 1929: 292–293, emphasis modified; cf. Bertalanffy 1932: 100–101; Needham 1937 [1943: 234])