Question

In the study of cognitive linguistics, the theory of linguistic determinism—which posits that the morphological and syntactic structures of a language dictate the cognitive processes of its speakers—has recently experienced a controversial revival. A prominent faction of cognitive anthropologists has applied this theoretical framework to languages featuring mandatory evidentiality. Evidentiality is a grammatical system requiring speakers to explicitly encode the epistemological source of their information. In the Tariana language of the Amazon basin, for example, a speaker cannot simply state that a specific event occurred; they must append specific affixes to indicate whether they directly witnessed the event, deduced it from physical traces, or merely heard about it through secondhand transmission.

These anthropologists argue that this rigid grammatical requirement imposes a severe cognitive bottleneck on speculative reasoning. Their argument rests on the observation that during everyday speech, speakers of highly evidential languages must constantly monitor, evaluate, and categorize their epistemological sources. Because this continuous epistemological bookkeeping demands significant conscious attention and working memory, the anthropologists conclude that these speakers are left with insufficient cognitive bandwidth to engage in the unconstrained, abstract theorizing that is the hallmark of advanced speculative philosophy. Consequently, they suggest that the obligatory nature of evidential grammar inherently limits a culture’s capacity for sustained abstract philosophical discourse.

However, this anthropological conclusion is fundamentally flawed on multiple fronts. First, it ignores the rich, highly abstract mythological and cosmological traditions prevalent in many cultures with evidential languages, traditions that require immense speculative imagination. Furthermore, the anthropologists' argument assumes a deeply reductionist view of human cognition. While linguistic processing undoubtedly requires cognitive resources, recent neuroimaging studies suggest that obligatory grammatical encoding and high-level abstract conceptualization operate through largely parallel, functionally independent neural pathways. Thus, the continuous source-monitoring required by evidential grammar is more likely an automatized, subconscious background process rather than a parasitic drain on the executive cognitive functions necessary for speculative thought.

The cognitive anthropologists' conclusion that mandatory evidential grammar inherently limits a culture's capacity for sustained abstract philosophical discourse logically depends on which one of the following unstated assumptions?