We have to consider again ... the private individual, and ... the laws of his behaviour; only we have now more things to take into account. We have to consider the ways in which his conduct may be affected, not only by present prices, but also by interest rates, and also by price- and interest-expectations; we have to examine, not only his demand and supplies of commodities, as before, but also his demand or supply of securities (including ... money). We have to make a similar investigation for the case of the firm. Then ... we have to bring these laws together to give us laws for the working of the whole price-system.Although the author perceives it will be difficult to proceed much beyond a temporary equilibrium analysis (such as how the dynamics might work during a particular "week"), he will endeavor "to see what can be said about the laws of development of the price-system through time."
The author notes that "firms probably work out their production plans a good deal more fully than private individuals work out their expenditure plans." There are advantages of presenting an "analysis of the determination of a plan" in a more realistic case; therefore, the discussion will consider first the behavior of the individual firm, and will proceed after that with the study of the individual person.