At this point, there are a number of options on the table. One is to deny that genes, cells and other biological structures literally traffic in information in ways that explain their behaviour, but to argue nevertheless that this is a useful analogy or model. The idea is that there are useful similarities between paradigm cases of information and representation using systems—cognitively sophisticated agents, thinking and communicating with one another—and biological systems. Hormones, for example, are usefully thought of as messages because they are small, stable, energetically inexpensive items that can travel long distances (relative to their own size) without decaying, to specialized locations where they have predictable, specific, and important effects on arrival. But while this is a helpful way of thinking, perhaps we should not take talk of messages too seriously. For example, we should not treat a question about whether prolactin is a report of pregnancy or an instruction to the mammary glands as if it had a literally correct answer. Arnon Levy has developed the most sophisticated version of this view of biological information (Levy 2011). 