Actions Interactions
unintended consequences
choices
apply means to ends according to information
unintended orders are formed from people's self-interested actions and interactions.

All choices imply trade-offs.

air suddenly becomes scarce. it changes your behaviors. because your incentives changes. marginal benefit of air suddenly increases, so you will try to get more air.

cost goes up => do less of it
cost goes down => do more of it
benefit goes up => do more of it
benefit goes down => do less of it

people choose at margin
all costs are marginal costs
all benefits are marginal benefits

all voluntary trades are mutually beneficial

before-hand, we think trade is beneficial