Economics as a social science with models
Economics studies how people use scarce things to meet their wants. It is a social science because it studies people, not stones. People can change their minds, so economic 'laws' are not like gravity. They are tendencies that hold when other things stay the same.
Economists use models: simple pictures of the real world. A model keeps the key parts and leaves out the rest. Many models use maths: a demand line, a graph, an equation. Maths makes ideas exact, so we can test them with data. A model is useful, not perfect. If the data disagree, we change the model.
- Law: a pattern seen again and again (for example, a higher price usually means less is bought).
- Model: a simplified map of a situation, often written in maths.
- Limit: a model is true only under its assumptions.
The individual view and the social view
Methodological individualism means: to explain what happens in society, start from the choices of single people. A market price, for example, is the result of many buyers and sellers each deciding for themselves. It is a method, not a belief that people live alone.
The sociological view (holism) says groups matter in their own right. People live inside norms (unwritten rules), institutions (schools, laws, markets) and networks. We copy friends, follow customs and feel pressure from the group. A fashion or a bank run spreads because of links between people.
Both views help. The individual view is simple and good for models. The social view explains trends, customs and why the same person acts differently in different groups. Modern economics uses both.
Limits of rationality and behavioural economics
Simple models assume a rational person who knows every option and picks the best. Real people have limited time, information and brain power. This is bounded rationality. We use shortcuts (heuristics) and pick an option that is good enough.
Behavioural economics joins psychology and economics. It uses experiments to find the common, predictable mistakes called biases, for example anchoring on the first price we see, or hating losses more than we like gains. See the lesson on behavioural economics for the full list.
This does not make models useless. It tells us where they work (large markets, simple choices) and where they may fail (big, rare, emotional decisions).
Utility, efficiency, equity and wellbeing
Utility is the satisfaction a person gets from a good or an action. We cannot measure it directly, so economists look at choices and incomes. Wellbeing is wider: health, education, safety, free time and a clean environment also count, not only money. That is why a country can be richer in money but not happier.
Efficiency and equity
Efficiency means getting the most from scarce resources, with no waste. It is about the size of the pie. Equity means fairness in how the pie is shared. People disagree about what is fair: equal shares, shares by need, or shares by effort.
The two can pull in different directions. Taxing the rich and giving to the poor raises equity, but the system may lose some output on the way (like a leaky bucket: collecting, paying staff, changing work choices). Policy-makers must trade off the two. That choice is a value judgement, so it is a normative question and not only a question of facts.
Economics, ecology and the circular economy
Ecology studies living things and their surroundings. The economy is a part of nature: it takes resources (water, soil, metals, energy) and gives back waste. If we use resources faster than nature renews them, growth cannot last. This is the idea behind sustainable development: meet today's needs without harming the future.
A linear economy runs in a line: take, make, throw away. Waste piles up and raw materials run out. A circular economy runs in a loop: design things to last, reuse them, repair them and recycle the materials. Less new material is needed and less waste is made.
Some costs fall on others: factory smoke harms neighbours who did not buy anything. These are externalities. Ecology helps economists count such costs, for example by taxes on pollution or rules for recycling.
Try it
Try it at home. Take 10 coins or bits of paper. Give 8 to one friend and 2 to another. Ask both: 'Is this fair?' Now move 2 coins, and drop 1 on the way (it 'leaks'). Count the total and the gap again. In the 3D, use the slider and compare. Then look at your house bin: list three things you could reuse or repair instead of throwing away.
Key formulas and definitions
- Economics = social science: people choose, so laws are tendencies (other things equal)
- Model = simple picture of reality; often written in maths; true under its assumptions
- Methodological individualism: explain society from single people's choices
- Sociological view: groups, norms and institutions also shape choices
- Bounded rationality: limited information, time and brain power, so 'good enough' choices
- Utility = satisfaction; wellbeing = utility plus health, education, safety, environment
- Efficiency = biggest total (no waste); Equity = fair shares
- Linear: take, make, waste. Circular: reuse, repair, recycle
Worked examples
1. Why is an economic 'law' such as 'higher price, lower demand' not like a law of physics?
Step 1: Economics studies people. Step 2: People can change their minds and are shaped by habit, income and mood. Step 3: So the pattern holds only on average and only when other things stay the same. Step 4: It is a tendency, not an exact rule.
2. A shop sees many people buy a new snack after one popular student posts about it. Which view explains this better, individual or sociological? Why?
Step 1: Each buyer decides alone, but the posting spread along friend links. Step 2: Copying others is a social effect. Step 3: The sociological view explains it better, because it looks at norms and networks. Step 4: The individual view can still describe each purchase.
3. A student has 8 choices of phone plan. She reads 3 plans and picks the first that fits her budget. Is she irrational?
Step 1: Reading all 8 takes time and effort. Step 2: She chose an option that is good enough. Step 3: This is bounded rationality (satisficing). Step 4: She is not foolish; her reasoning has limits and a cost of search.
4. Rich person A has 8 coins, poor person B has 2. Government moves 4 coins from A to B but 2 coins are lost in costs. Find the new total and the new gap. Which went up and which went down?
Step 1: Start: total = 8 + 2 = 10, gap = 8 โ 2 = 6. Step 2: A gives 4, so A has 4. Step 3: B receives 4 โ 2 = 2, so B has 2 + 2 = 4. Step 4: New total = 4 + 4 = 8, new gap = 0. Equity improved (gap 6 to 0) but efficiency fell (total 10 to 8).
5. A factory makes 100 plastic toys, sells them, and the customers throw them away after use. Describe how a circular economy would change this.
Step 1: Now it is linear: take plastic, make toys, throw away. Step 2: In a circular plan the toys are made to last and to be repaired. Step 3: Old toys are collected, reused or recycled into new toys. Step 4: Less new plastic is taken and less waste goes to landfill.
Common mistakes
- Thinking methodological individualism means people live alone. It is only a method: explain society by starting from single choices.
- Saying efficiency and equity mean the same. Efficiency is the size of the pie; equity is how fairly it is shared.
- Believing a model must be exactly true to be useful. A model is a simple map; it is judged by how well it helps and tests against data.
- Treating wellbeing as the same as income. Health, education, safety and environment also count.