Economic theory comprises three types of inquiry. One examines economic phenomena, one develops analytical tools, and one studies the scientific endeavor in economics in general and in economic theory in particular. We refer to the first as economics, the second as the development of economic methods, and the third as the methodology of economics. The same mathematical result can often be interpreted as contributing to more than one of these categories. We discuss and clarify the distinctions between these categories, and argue that drawing the distinctions more sharply can be useful for economic research.