1.2 How do economists approach the world?

• Positive economics uses logic, hypotheses, models, theories, ceteris paribus, empirical evidence, and refutation

• Normative economics involves value judgments in policy making

• Equity and equality are distinct ideas and may be interpreted differently

• 18th century thought includes Adam Smith and laissez faire

• 19th century thought includes classical microeconomics, utility, the margin, Say's law, and Marxist critique

• 20th century thought includes the Keynesian revolution, macroeconomic policy, monetarism, and new classical counter-revolution

• 21st century thought includes behavioural economics, interdisciplinarity, sustainability, interdependence, and circular economy ideas