Fig. 8.1 Summary of incremental evolutionary steps
organizedbehavioristherefore poised toinventsyntax(seediscussionbyBloom1994a). Rather,eachexpansioninthe
range of the organism's behavior must potentially be regarded as an independent evolutionary step.
The steps I propose are summarized in Fig. 8.1. Logically sequential steps are ordered top to bottom; logically
independent steps are presented side by side.
8.3 The use of symbols
The most important preconditions for language are already demonstrably present in primates: there must be a
community of individuals who have thoughts worth communicating to each other. I take it as established by decades
of primate research (Köhler 1927; Cheney and Seyfarth1990; de Waal 1996; Tomasello 2000b, among many many
others) that chimpanzees have a combinatorial system of conceptual structure in place, adequate to deal with physical
problem-solving,withnavigation, and above all with rich and subtle social interactionincorporatingsome sense of the
behavior patterns and perhaps intentions of others.