Ceteris Paribus
All other things remain unchanged
e.g. If price increases quantity demanded should fall, ceteris paribus
Used because IRL any change in an economic variable is likely to cause a change in others
Classical economics assumptions - Homo Economicus
Homo economicus is the assumption made in classical economics that individuals are always rational and act in their economic self-interest. That firms are profit maximisers and consumers are utility-maximisers. This is not always the case (see behavioural economics).