A central theme in the scientific iter of Pierangelo Garegnani is the study of the relation between theoretical values and effective magnitudes, namely the methodological aspects implicit in the theory of value and distribution. The aim of this contribution is to reconstruct and then clarify the Garegnani’s thought on this crucial relation.

According to the «surplus approach» to value and distribution, as Garegnani summarized the modern reappraisal of the classical theoretical standpoint of Smith, Ricardo and Marx, the rule of correspondence between theory and reality was intimately linked to the notion of «normal position» of the economic system, resulting by the spread of competition and, in the sense stressed in the paper, persistency.

Theoretical magnitudes – in the surplus approach, the values determined by the «Sraffa’s price equations» – were conceived as the centres around which market prices would have «gravitated». As a result, they would have emerged, with a certain approximation, as an average of the actual values over a period of time sufficient to allow for the repetition of transactions in free competition regime.

Following Garegnani’s argument, it is recognised the impossibility of studying systematically the actual positions reached by economic system, i.e. the exigence of focusing just on the average, regular phenomena. The analysis of changes can then be conceived exclusively by comparing the «normal positions» of the system before and after those changes.

The first section of this contribution concerns Garegnani’s interpretation of the method adopted in the surplus approach to value and distribution, and the connected notion of «normal position». As we will see, Garegnani’s standpoint is grounded on the logical separation between different analytical stages. First, the «core» of the approach, in which we can find general relations determining, by deductive method, normal prices and the general rate of profit. Conversely, «outside the core» accumulation, distribution, and other less general relations can be studied by a more inductive method.

The second section of our contribution investigates the consequences of the assumption of given outputs on the determination of normal values. Subsequently, it is introduced fixed capital and the detection of the «dominant technique», the role of market prices’ gravitation – related to the emergence of the general rate of profit – and the quantities’ gravitation, evaluating also the consequences on capital accumulation and economic growth.

Keywords: Garegnani, normal position, surplus approach, economic methodology, classical theory of value, gravitation.