Value, then, is a much less comprehensive conception, and does not emerge till a certain limitation is put upon this utility. But the limitation in question is not an arbitrary one. To drain a river of a few hundred gallons, or even to drain it all but a few hundred gallons, will not necessarily give the remainder any value. To change utility into value there must be, not only a capability of satisfying want, but a felt dependence of some want on the particular good containing the utility. The relation of value to utility, in fact, may be described as the relation of a positive condition to a capability. As capable of quenching thirst, all water is useful, but it does not obtain any value till some limitation of the available quantity makes it the indispensable _condition_ of a satisfaction. The water led into a city may come from a stream which, as a whole, flows to the sea unvalued, but, in the city, it conditions the wellbeing of thousands of people, and obtains a value from the satisfaction of wants that are conditioned by it. If, then, the distinction between Value and Utility, which seems essential to clearness of thinking, is to be maintained, it will be by attaching the former to an indispensable and felt condition, the latter to a general capability of ministering to human wellbeing. Thus we may say that, while utility is the importance which a good possesses as generally _capable_ of ministering to the wellbeing of a subject, Value is the importance which a good possesses as the _indispensable condition_ of the wellbeing of a subject. Or more fully: Value is the importance which a good acquires as the recognised condition of something that makes for the wellbeing of a subject, and would not be obtainable without the good.[8] It cannot be too firmly grasped then, that the relation between utility and value is _quantitative_, and that the same thing may or may not have value according to change of circumstances, or difference in points of view and comparison. [8] Menger’s definition is “Die Bedeutung, welche concrete Güter oder Güterquantitäten für uns dadurch erlangen, das wir in der Befriedigung unserer Bedürfnisse von der Verfügung über dieselben abhängig zu sein uns bewusst sind.”—_Grundzüge_, p. 78.