Usually these refer to conditions under which debt should not be used as a solution, e.g. to fund consumption for survival. Consumer debt and public debt deal with some of these issues.

Some theories of economics argue that debt is itself a problem, and should not be the foundation on which contracts are made between persons, organizations and nation-states. Those theories that hold it as wholly undesirable are often called creditary economics, and are also often related to theories of economics that look more basically at fundamental scarcities: clean air, clean water, safe food, shelter:

On the other hand, debt instruments (such as bonds or loans) are often seen as means of effective transfer of money from people that have excessive funds to people with productive investment ideas. This lets the economy increase it's efficiency, meaning an increase of the well-being of the whole society. (E.g. an entrepreneur comes to a bank with a great idea and gets a loan, which is one of the debt instruments. He uses the money to develop his idea into a working company, creating products and work places - increasing overall well-being).

The most important practical theory in understanding many aspects of debt is the theory of time value of money, this is the theory that is daily used in finance for comparing one debt instrument to another. It also explains such phenomenas as fluctuation of bond prices with the change in the interest rates etc.

Part of the time value of money theory is the concept of present value and future value used for example in calculating mortgage terms.

All text is available under the terms of the GNU Free Documentation License (see Copyrights for details).