A measure for distinguishing the absolute and relative worth of a thing (an object or a service) both to its owner and to others. Intrinsically hierarchical, value is used in a number of different disciplines. It is theorized in two main ways, as an ethical problem and as an economic problem (recent work in sustainability studies tries to combine these two problems so that the ethical choice and the economic choice are one and the same thing). Ethics uses value as a means of determining the difference between the various ideas and concepts impacting on everyday life, such as the notions of freedom and life which come into conflict over issues like the right to life of the unborn foetus versus the right to decide of the mother, or equally problematically the right to die of terminally ill patients versus the medical professionâs commitment to life. As both Foucault, Michel and Agamben, Giorgio have pointed out, however, placing a value on life in this way has given rise to a new form of governmentality that they both describe as biopower. In economics, it is Marx, Karl, above all others, who has devoted the most effort to thinking through what value means. But his theory builds on a long line of philosophical inquiry, beginning with Aristotle who first observed that there is a difference between the use-value of a thing (what a thing is worth to a person who actually uses it) and the exchange-value of a thing (what another person would be willing to trade for a particular thing). In use-value it is the intrinsic physical properties of the thing itself which are determinant (e.g. one axe can chop wood better than another because it is made from better materials); while exchange-value is a social construction and varies constantly according to the whims and tastes of a particular society (e.g. fashion). Aristotle saw as aberrant the fact that (putting it in contemporary terms) a car could have a higher value than a house, when the latter is obviously of far greater use to its owner than the car. Marx saw this state of affairs as normal in capitalism and set out to explain it, basing his theory of value, the so-called âlabour theory of valueâ, on classical economist David Ricardoâs famous work Principles of Political Economy and Taxation (1817). Marx defined value relative to the âsocially necessary abstract labourâ embodied (or stored) in a given commodity. If a table takes 10 hours to produce and a car 10,000 hours to produce then the car is more valuable than the table. This fact is obscured by the way that money (which for Marx is a commodity) standardizes the exchange-value of all things.