In order to provide an alternative to the Cartesian myth that knowledge of our thoughts and sensations is "given," Sellars posits a community of "Rylean ancestors" -- humans at an early stage of conceptual development who possess a language containing sophisticated concepts about the physical world and about their own language and behavior, but who lack any concepts of thoughts or sensations. Sellars's presentation of this thought experiment leaves many important details sketchy. In the following dialogue, we offer our differing assessments of how well those details could be filled out. TT questions how the Rylean hypothesis could provide a plausible account of human thought and sensory experience at any stage of human conceptual development. WdeV responds to TT's challenge by filling out the picture of what the Rylean's conceptual world would look like. TT and WdeV debate the merits and the plausibility of the resulting picture.