Category Archives: Consumer Theory

Alfred Marshall (1842 – 1924)

Alfred Marshall made lasting contributions to economics. No economist will question that. However, his precise contributions to economics are often forgotten. In a way, the microeconomics that we learn and apply today has strong Marshallian foundations. This post draws on Peter Groenewegen’s excellent (concise) biography of Alfred Marshall (2007) which has been published as part of the Great Thinkers in Economics Series published by Palgrave Macmillan.

Marshall is most famous for his Principles of Economics first published in 1890; the definitive eighth edition was published in 1920. In addition, he wrote Industry and Trade (1919), Money, Credit and Commerce (1923) and Economics of Industry (1879) which he wrote along with his wife, Mary Paley Marshall. Besides these, he also printed and privately circulated his work entitled The Pure Theory of Foreign Trade. The Pure Theory of Domestic Values (1879). Overall, he taught for more than forty years in Bristol, Oxford and Cambridge. The most notable among his students are John Maynard Keynes and Arthur Cecil Pigou.

He took German lessons in order to read Kant in the original. Hegel’s Philosophy of History had a strong influence on his thought. Marshall commenced his study about economics with a close reading of John Stuart Mill’s Principles of Political Economy. He also read the methodological works of Mill on logic and particularly criticised Mill’s conception of the individual as a ‘self-seeking, wealth-maximising homo economicus’. His other economics readings included Smith’s Wealth of Nations, Ricardo’s Principles and Marx’s Capital. Other important influences were Cournot’s Mathematical Investigations in the Theory of Wealth and von Thunen’s The Isolated State; they motivated Marshall’s use of diagrams.

For Marshall, ‘the proper work of economic science…was solving economic problems’. ‘The necessity of economic theory, the importance of facts and continual striving to keep economic analysis relevant and practical were all crucial parts of Marshall’s promise to devote his professional life to the improvement of economic science’ (p. 74). It is also quite well known now that, for Marshall, the ‘mecca of the Economist lies in Economic Biology rather than in Economic Dynamics’ (p. 106).

Groenewegen informs us that Marshall had a personal dislike of the use of textbooks in university teaching (p. 77). Not surprisingly, ‘[t]he Principles of Economics remained a leading textbook on the foundations of economics not only during the life of its author, that is, from 1890 to 1924, but for the next quarter century as well, that is, until the early 1950s’ (p. 111).

The use of mathematics in the Principles has garnered lot of attention since he ‘banished’ all equations to the appendix. In any case, Marshall considered economics as ‘form of reasoning’. Perhaps, given the use of mathematics during his time, his relegation of equations to the appendix might have been appropriate. I quote an interesting letter Marshall wrote to his student Bowley: ‘(1) Use mathematics as a shorthand language, rather than as an engine of inquiry. (2) Keep to them till you have done. (3) Translate into English. (4) Then illustrate by examples which are important in real life. (5) Burn the mathematics. (6) If you can’t succeed in 4, burn 3. This last I did often’ (p. 114).

Marshall identified time to play an important role in the theory of value. He developed the concepts of the short and long period. He paid particular attention to ‘elasticity’. Besides these, he laid the foundations for the theory of the firm, use of offer curves or reciprocal demand curves in international trade and distinguished internal and external economies.

This post has only very briefly touched upon the way Marshall viewed economics, especially his use of mathematics and his evolutionary notion. We have not detailed his precise contributions to economics. This post serves the purpose of being a very short introduction to Marshall. As students of (micro)economics, it will be fascinating to read Marshall’s works, especially his Principles.

Utility in Microeconomics: Outdated?

This post clarifies the concept of a utility function, which occupies a very significant position in neoclassical microeconomics. Advances in neuroeconomics and related fields of behavioural economics is constantly challenging the conventional assumptions of microeconomics. This post takes up one such insight by Stephen B Hanauer which was published in Nature in March 2008.

A utility function can be understood in the following way:

U=f(x,y,z) where U is the utility derived from the consumption of x, y and/or z. Alternatively, a utility function transforms combinations of various goods into a single value. Note that x,y and z refer to ‘quantities’ of goods/services consumed.

Suppose, consumer A has the following utility function: U=x+y+z; arbitrary values of x,y and z would result in the following values of U.

x y z U
0 0 0 0
1 0 0 1
10 10 0 20
6 6 8 20
0 10 10 20
10 10 10 30

That is, microeconomics teaches us that the utility of the consumer is determined by the quantity of goods consumed. An common assumption is that ‘more is better’, which implies that the consumption of more goods gives the consumer more utility. The point to be noted is that microeconomic theory teaches us that utility is strictly a function of quantities. The question posed in this post is whether utility is ‘only’ a function of quantities. What happens if utility is also a function of prices? At this juncture, we need to recollect the objective of utility functions. From the utility function, we derive indifference curves and marginal utilities. Utility or use value of the good or service forms the basis of the demand function, which along with the supply function determines the value/price of a commodity or service. Thus, the use value was employed so as to arrive at the exchange value/relative price of the commodity.

What happens if utility (or experienced pleasantness) is influenced by “changing properties of commodities, such as prices”? That is, can neoclassical microeconomics accomodate the following utility function:


And research in behavioural economics and related areas suggest that prices exert a significant influence on utility and hence on choice and demand. However, if we accept such a utility function, it can no longer be used to explain exchange values/relative prices. Another implication is that prices are no longer determined by the interaction of demand and supply. And the statement that ‘consumer is the king’ no longer holds. Also, producers can adjust prices in such a way as to affect consumers’ utilities. We know that high prices are often associated with better quality and hence higher utility.

x y Px Py U
0 0 10 10 0
10 10 10 10 200
10 10 5 10 150
10 10 4 4 80

The above table can be explained by the following utility function: U=x.Px + y.Py

In this case, a higher price gives more utility to the individual. The maximum utility is when x=y=10 and Px=Py=10.

The other extreme case is when high prices are detested by the individual. For instance, consumers with low incomes will get more utility from consuming goods which are priced less. Their utility function could be represented as follows: U=x.-Px + y.-Py

In which case, the consumers utilities based on the previous values of x,y,Px and Py will be 0, -200, -150 and -80. And the consumer’s utility is maximum when he/she consumes x=y=10 when Px=Py=4.

Empirical evidence suggests that utility is equally influenced by prices of commodities as well. Does this threaten the core of neoclassical microeconomics? This is problematic because neoclassical economics assumes the following to be given: 1) tastes and preferences of individuals, 2) endowments of goods and 3) constant technology. It if from these ‘givens’ that prices and quantities (demanded and supplied) are arrived at through the mechanism of demand and supply/competition/market forces. How can we include the recent findings pertaining to consumer utility and satisfaction in a consistent manner?


The link to the reference was embedded in the authors name. However, because of the comment by Dr. Thomas Alexander, the reference is prrovided below. Also,I acknowledge him for bringing this article to my notice.

Hanauer, S (2008), ‘Experienced Pleasantness,’ Editorial, Nature Reviews Gastroenterology and Hepatology 5, 119 (1 March 2008).

Paul Samuelson: The Father of 'Modern Economics' Dies

All those who have studied economics for the past 50 years or so have heard about Samuelson – Foundations of Economic Analysis, Samuelson-Stopler theorem, Factor-price equalisation theorem, revealed preference theory, Bergson-Samuelson social welfare functions, non-substitution theorem, linear programming in economics, etc. The first one is his 1947 book which dominates economics teaching even today, directly or indirectly. Samuelson transformed economics into some sort of science (pseudo-science, as some call it)-social physics. [For more on this, go here]

Robert Lucas on Samuelson:

“Samuelson was the Julia Child of economics, somehow teaching you the basics and giving you the feeling of becoming an insider in a complex culture all at the same time. I loved the Foundations. Like so many others in my cohort, I internalized its view that if I couldn’t formulate a problem in economic theory mathematically, I didn’t know what I was doing. I came to the position that mathematical analysis is not one of many ways of doing economic theory: It is the only way. Economic theory is mathematical analysis. Everything else is just pictures and talk.” [Marginal Revolution and here]


In his Foundations, he is supposed to have popularised the views of Keynes. In fact, what he popularised is the neo-classical synthesis (IS-LM curves, which were created by Hicks). Hence, what we learn in most macroeconomics texts is not what Keynes said. Post-Keynesian economics is more closer to what Keynes said.

Despite his ‘ideas of good economics’, one needs to appreciate the works he carried out in different areas in economics – macroeconomics, public finance, international trade, consumer theory, capital theory and general equilibrium, etc.

In his initial editions of the Foundations, one could find a few pages devoted to the 1960 capital theory debates. However, with passage of time, the debate was relegated to footnotes. Now, in mainstream textbooks, capital theory is entirely omitted. In fact, Samuelson admitted the problems neoclassical microeconomics and general equilibrium run into because of their notion of capital. [More here]

I end with two questions.
Is mathematics the only way of studying economics and analysing economies? [We mostly use calculus and game theory. Should we employ other kinds of mathematics?]

How reliable are textbooks? It makes learning easy, but probably, a bit too easy.

On Perfect Information

Four persons A, B, C and D have to share Rs 4 among themselves in units of one rupee. First A proposes a distribution and all of them, including A vote on it. If at least 50% of those voting agree with A, the proposal is accepted. If not, A loses her voting rights and B gets to propose a distribution and all except A vote on it. Once again B’s proposal is accepted if at least 50% of those eligible to vote agree on it. If not, B also loses her voting rights and C gets to propose and so on to D. Assume that each person prefers more money to less and will always vote against a distribution in which she gets zero. What distribution would A propose?

This is a sequential game. It is one in which players make decisions (or select a strategy) following a certain predefined order, and in which at least some players can observe the moves of players who preceded them. If no players observe the moves of previous players, then the game is simultaneous. [Game]

This is also one of perfect information. If every player observes the moves of every other player who has gone before her, the game is one of perfect information. [Game]

In the sequential game with perfect information, A will propose 3 for himself and 1 to D. This will be accepted by both A and D. D will accept anything more than 0; the reason being that, if all the proposals are rejected and the 4 rupees come in Cs hand, he will take all 4 for himself and since he will will vote for himself, the proposal will get accepted.

In such a game, the one makes the move first will have undue advantage.

On Perfect Competition

This market environment is extensively studied in Economics and is considered as a “Perfect” environment especially on the basis of efficiency.

This write up explains the concept of perfect competition succinctly.

Is such an environment favourable for all ? Competitive markets emphasise the importance of having perfect information as a pre requisite for a competitive equilibrium; one which is also Pareto Efficient.

The consumption decisions taken are sequential in nature. The consumer decides to purchase the commodity or service keeping in mind the price; which has been fixed earlier keeping in mind the consumers preferences. The outcome will always favour the producer (In a perfectly competitive market) as he makes the decision of pricing first.

On Pareto Efficiency

An outcome of a game is Pareto efficient if there is no other outcome that makes every player at least as well off and at least one player strictly better off. That is, a Pareto Optimal outcome cannot be improved upon without hurting at least one player. [Game]


If the objective in an economy is Pareto Efficiency, then it can be achieved by a competitive market. But, it does not take into consideration equity in distribution. For example, in the game mentioned above, an allocation which leaves A with all the 4 rupees is Pareto Efficient, because in order to make someone better off, A has to be made worse off.

In India, the objective is to reduce Poverty and make growth more wide spread rather than growth being segregated in nature.

The idea that we cannot achieve the ideal state of perfectly competitive market equilibrium might seem pessimistic. Some economists insist upon holding the capitalist system to a standard of competitive equilibrium. Failure to meet this standard constitutes a “market failure” that warrants government intervention.[MacKenzie 2006]

So, is a market environment with perfect information desirable?