 The core of Millikan’s biosemantics consists of two claims. The first is that all representations are, at bottom, messages sent from a producer to one or more consumers. In other words, representations always stand midway between (i) a producer system that is supposed to generate them and (ii) one or more consumer systems that are supposed to respond to them in specific ways. According to Millikan, these systems must be designed to cooperate with each other, either by natural selection or by a process of individual   learning.[9]  (Note that Millikan’s terminology varies; in some of her writings, producers are described as ‘senders’, representations as ‘intentional icons’ or ‘intentional signs’, and consumers as ‘receivers’ or ‘interpreters’.)