Marshall’s third “book” in his book volume on Principles of Economics is “on wants and their satisfaction.” This chapter contextualizes that topic (demand/consumption), thereby setting up Book 4 (production) and Book 5 (“a general theory of demand and supply”). These topics (and their order) will be familiar to a modern reader, but Marshall is innovating here by discussing demand and supply ahead of the traditional focus of economics (“the production, distribution, exchange and consumption of wealth“), which is pushed into Books 5 and 6 (distribution and exchange of value).
§2. Economists have neglected demand and consumption because they result from the decisions of individuals, which implied — since the logic of such dynamics was “the common property of all sensible people”– there was “nothing” for economists to explain [p71].
Marshall is challenging that norm because of (1) a prejudice to studying production and supply, (2) new mathematical techniques uncovering ignorance of demand,* (3) new statistical measures of demand, and (4) a social pivot from creating wealth to using wealth to improve individual and collective well-being. This last, significant point remains underemphasized in a world that focuses too much on GDP and too little on well-being. Yes, wealth contributes to well-being, but so do many non-wealth factors (friendship, beautiful surroundings, or collective institutions to protect individuals from coronavirus).
[How convenient! In April, I am teaching an (online, closed) course on growth and development, synonyms for production and well-being , respectively.]
* Marshall’s colorful language is worth reproducing:
It is indeed doubtful whether much has been gained by the use of complex mathematical formulæ. But the application of mathematical habits of thought has been of great service; for it has led people to refuse to consider a problem until they are quite sure what the problem is… [p71]
Thus, the book will begin by looking into human wants (demand) as a complement to our efforts and activities (supply), which has received too much attention (in Marshall’s eyes) due to Ricardo and followers asserting that wants are animal and instinctual whereas efforts and activities are the main output of humanity.
Although I (as Marshall) see their point — we talk much more about firms, markets and products than the happiness of consumers — I agree with Marshall that demand needed needs more study. I say this because even today we do not really understand or promote human happiness (safety, friendship, respect, meaningful work, and so on) relative to human activities (production), which has left us blind to non-production policy and life-style paths. The results of our myopia are unsustainability, inequality, misery, and other problems that economists could really address — if they reprioritized.
A promising beginning.