Abraham Lincoln gave a classical definition of human exploitation in a simple sentence:  “It is the principal that says you work and toil and earn bread and I will eat it.”

Exploitation of nature and of fellow beings by man began long before written history.  During periods of civilization, and notably in present-day civilization, exploitation has determined social relationships.  It has also become one of the pillars of every civilized community.

Civilized peoples use up natural resources as a matter of course.  The more advanced technically have stripped their environments of replaceable and irreplaceable resources.  They have also perfected techniques for using the productive power of their fellow creatures.  One way to do this is by owning the body.  Another way is ownership of land, capital and consumer goods which enable the owner to live without labor on the products resulting from the labor of others.

Owners of property and wealth receive an income because they are owners.  They may be very young or very old, able-bodied or helpless.  Their livelihood comes to them not because of anything they do, but because of the property titles which they own.

The owner of land may collect rent.  The owner of capital may collect interest.  The owner of an enterprise may collect profits.  Each lives by owning.

Workers produce goods and services.  They are paid an income proportioned to their production.

Owners of land, capital and consumer goods are paid incomes proportioned to their ownership.

Workers work for a living.  Owners live by ownership, chiefly of land and the implements of production.

Owners of property frequently are rich.  Workers, by comparison, are poor.  The line separating owners from workers also separates riches from poverty.

Income from services rendered, from work, is earned income.  Income from property ownership, by contrast, is unearned income.

The relation between earned and unearned income is not confined to one generation.  Under laws passed by the owners and their retainers the owners of private property may give or bequeath this property to their descendants.  In the course of time a community is divided between workers who are poor and owners who are rich.  Since the rich need not work in order to live, they and those associated with them may live on the unearned income derived from property ownership.  In a word, they may become parasitic.

Parasitism may lead to social decay.  Generation after generation, the owners and their dependants may live in comfort or even in luxury while those who work and their dependents may lack simple necessities.  This is the confrontation of riches and poverty which has played so large a role in every civilization.

Through the ages, in one civilization after another, the glaring contrast between riches and poverty has appeared, dividing the community and laying the foundation for class struggle and class war, both of which decrease social efficiency, intensify class antagonism.