Income No. 3 must be defined as the maximum amount of money which the individual can spend this week, and still be able to spend the same amount in re… - John Richard Hicks

The best of all monopoly profits is a quiet life.

We must give the system sufficient factors of stability to enable it to work; but we must not assume that these forces are so powerful as to prevent the system from being liable to fluctuations. There must be a tendency to rigidity of certain prices, particularly wage-rates; but there must also be a tendency to rigidity of certain price-expectations as well, in order to provide an explanation for the rigidity of these prices... Indeed we should do better to assume a good deal of variation in different people’s elasticities of expectations... Of course the way in which a population is divided with respect to this sort of sensitivity will vary very much in different circumstances... We have to be prepared to deal with a range of possible cases, varying from that of a settled community, which has been accustomed to steady conditions in the past (and which, for that reason, is not easily disturbed in the present), to that of a community which has been exposed to violent disturbances of prices (and which may have to be regarded, in consequence, as being economically neurotic.

The purpose of income calculations in practical affairs is to give people an indication of the amount which they can consume without impoverishing themselves. Following out this idea, it would seem that we ought to define a man's income as the maximum value which he can consume during a week, and still expect to be as well off at the end of the week as he was at the beginning.