I admit that these terms and the diagrams connected with them repel some readers, and fill others with the vain imagination that they have mastered difficult economics problems, when really they have done little more than learn the language in which parts of those problems can be expressed, and the machinery by which they can be handled. When the actual conditions of particular problems have not been studied, such knowledge is little better than a derrick for sinking oil-wells erected where there are no oil-bearing strata.
Alfred MarshallSlavery was regarded by Aristotle as an ordinance of nature, and so probably was it by the slaves themselves in olden time.
Alfred MarshallBut if inventions have increased man's power over nature very much, then the real value of money is better measured for some purposes in labour than in commodities.
Alfred MarshallMaterial goods consist of useful material things, and of all rights to hold, or use, or derive benefits from material things, or to receive them at a future time.
Alfred Marshall