1. Introduction to Economics
Economics is the social science that studies the production, distribution, and consumption of goods and services. At its core, economics examines how societies allocate scarce resources among competing uses and how individuals, firms, and governments make decisions under conditions of uncertainty.
“It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest.
— Adam Smith, The Wealth of Nations (1776)
1.1 What Is Economics?
The discipline divides broadly into two branches: microeconomics, which studies individual agents and markets, and macroeconomics, which examines the economy as a whole, including output, employment, and price levels.
Economics — The study of how societies use limited resources to produce valuable commodities and distribute them among different people.1
1.2 Scarcity and Choice
The fundamental problem of economics is scarcity: human wants are unlimited, but resources are finite. Every choice implies a trade-off, and every trade-off has a cost. This opportunity cost — the value of the next best alternative forgone — is the essential concept that underlies all economic reasoning.
Opportunity Cost — The value of the best alternative that must be given up when a choice is made. If a farmer uses an acre of land to grow wheat, the opportunity cost is the corn that could have been grown on that same acre.
2. Supply and Demand
The theory of supply and demand is the organizing principle of the market economy. It explains how prices are determined, how resources are allocated, and why markets tend toward equilibrium — a state where the quantity demanded by buyers equals the quantity supplied by sellers at a given price.
2.1 The Law of Demand
The law of demand states that, all else being equal, as the price of a good increases, the quantity demanded decreases, and vice versa. This inverse relationship is one of the most reliably observed patterns in economics.2
Law of Demand — Ceteris paribus, the quantity demanded of a good falls when the price of the good rises, and rises when the price falls.
2.2 Market Equilibrium
Market equilibrium occurs at the price where the quantity demanded by consumers equals the quantity supplied by producers. At this price, there is no tendency for change: no surplus drives prices down, and no shortage drives prices up. The equilibrium price is sometimes called the market-clearing price.
“The long run is a misleading guide to current affairs. In the long run we are all dead.
— John Maynard Keynes, A Tract on Monetary Reform (1923)
3. Behavioral Economics
Behavioral economics integrates insights from psychology into economic models, challenging the assumption of perfect rationality that underlies classical theory. Pioneered by Daniel Kahneman and Amos Tversky, this field demonstrates that human decision-making is systematically influenced by cognitive biases, heuristics, and framing effects.
Bounded Rationality — The idea that human decision-making is limited by available information, cognitive capacity, and time. Rather than optimizing, individuals "satisfice" — choosing an option that is good enough rather than the absolute best.
The implications for policy are profound. If individuals do not always act in their own best interest, then "nudges" — subtle changes in the choice environment — can improve outcomes without restricting freedom of choice.
Notes
- Paul Samuelson, Economics: An Introductory Analysis, 1948.
- Alfred Marshall, Principles of Economics, 1890.