Complex Dynamic Systems Theory (CDST) has received considerable attention over the last decades, inspiring a number of second language acquisition studies. This article examines the research from a critical epistemological point of view, starting from the Greek philosopher Cratylus, who concluded that remaining silent is the only way to be entirely coherent with the idea that everything is complex and dynamic. An alternative to this drastic conclusion may consist in 'saying without saying too much', that is, setting some limits to theorizing and empirical inquiry. Problems of description, prediction and generalization in a CDST framework are discussed, pointing to some open issues to be addressed by future research. Finally, some proposals are made for a more constructive research program, which may even involve abandoning the 'CDST' label.