A Big World of Rules?

To establish criteria and theoretical possibilities for rules and exceptions in biology, it is helpful first to analyze what a rule is, as well as its many variants. This chapter presents some hierarchical levels of rules in biology, with examples of the most comprehensive and the most restrictive. In both contexts, we discuss the concepts of laws, rules, and patterns and how these boundaries are not always so clear. The topic of the search for universal laws in biology is introduced. In this context, the phenomena of emergence, biological complexity, and others are mentioned. We analyze when there are smaller rules, limited to a certain field within biology. We see as some introductory examples when there are rules of behavior, ecology, and evolution. We also discuss the links between rules and epistemology, especially regarding paradigm shifts.