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.