![[Alfred_Marshall_1891.jpg]] *British economist [Alfred Marshall](https://en.wikipedia.org/wiki/Alfred_Marshall) invented the idea of Externality.* This is actually based on a principle I learned a long time before I began studying History. My original degree (after a long and very strange undergraduate career) was in a field called Agricultural Economics, that applied the ideas of both Macro and Microeconomics to food and natural resources. One of these ideas, which is ignored much of the time in mainstream economics but was key to a lot of natural resource economics, was the concept of [Externalities](https://en.wikipedia.org/wiki/Externality). These are defined as effects that are not the main point of the economic activity, and are typically *NOT* reflected in prices or other economic measures. Water pollution downhill from a mountaintop-removal coal mine would be an example, or noise from an airport near a residential area. These economically "external" effects can vary widely, both in intensity and importance. Sometimes they are mostly aesthetic, such as when people are annoyed with the look of wind turbines offshore in an expensive vacation resort area. Other effects are more serious, such as the loss of fish migration routes caused by industrial dams. The thing externalities have in common is that it is usually difficult to "put a price tag" on them. After all, there are ways of valuing things in the world that don't always translate easily into money terms. In addition, one of the three following factors often also plays a role: 1. The benefits of a change are often obvious and local; while the costs are often vaguer, harder to define, or dispersed. 2. The groups of people who benefit are different from those paying the costs. These groups typically don't have the same ability to defend their position; either because of power dynamics within a society (for example, social classes) or because they are *NOT* members of a single society (for example, colonialism). 3. Sometimes the costs are unanticipated consequences of the change, which don't appear until much later and may have been completely unknown to the people who made the change. You can probably think of many examples of externalities from your own experience. A good example from the ancient world is the transition to agriculture, and especially to settled farming of staple crops. Archaeologists have found that in early farm communities such as Abu Hureyra (Syria), skeletons show signs of damage to vertebrae, osteoarthritis, and deformed leg-bones leading them to conclude that the people (mostly women) working in early wheat farms had suffered injuries and physical damage from years of bending over and kneeling in fields. Skeletons of early farmers were also smaller and less robust than those of hunter-gatherers, and showed nutritional deficiencies. Pastoralists (herders) who had more access to meat and milk, did not share this decline in size or health. ----- Next: [[3.3 - Quantity vs. Quality]] Back: [[3.1 - River Valley Cities]]