Evolutionary Change and Marshall's Abandoned Second Volume (Reprinted from Economie Appliquee, vol 43, pg 85-98, 1990)

It is well known how in his later years, Alfred Marshall became less enamored with equilibrium methods of reasoning in economics and advocated instead the study of [evolutionary] biology. Some have alleged that Marshall's change of heart is what led him to abandon the project of preparing the second volume of his Principles of Economics. In this paper I deny that it was Marshall's commitment to evolutionary biology that held back volume 2. Rather, it may have been his stubborn commitment to a particular variant of evolutionary biology (that is, Spencer's version of evolutionary biology) that blinded him to the way a more far reaching synthesis of Darwinian and equilibrium notions might have been accomplished. The application of the modern biological synthesis might have enriched some of Marshall's earlier equilibrium notions such as the "representative firm". Il est bien connu que, dans ses vieux jours, Alfred Marshall devint moins amourache des methodes de raisonnement de l'equilibre en economique et preconisait a la place 1'etude de la biologie (evolutionniste). Certains ont allegue que c'est ce changement de noyau qui a conduit Marshall a abandonner son projet de preparation d'un second volume de ses Principes. Cet article denie que ce soit son engagement dans la biologie evolutionniste qui empecha le volume 2. Il se pourrait bien plutot que ce soit son engagement tetu dans une variante particuliere de la biologie evolutionniste (c'est-a-dire, la version de Spencer) qui lui ait bouche la voie d'une synthese de plus longue portee entre les notions de l'equilibre et de Darwin. L'application de la synthese biologique moderne aurait pu enrichir certaines des notions de l'equilibre initial de Marshall telles que celle de "firme representative".