Eugenio Rignano was an Italian positivist philosopher and founder (1907) and lifelong editor of the scientific journal Scientia. Rignano's first works were sociologically oriented, but he later turned to biology and philosophical biology.
His major work, Psicologia del ragionamento (1920), places the activity of memory at the basis of all biological and psychic phenomena. Memory is an activity that, through the specific accumulation of concepts, makes possible the progressive adaptation of the organism to the environment, the formation of instincts and emotions, and, in higher organisms, of reasoning.
According to Rignano, reasoning is "a series of operations or experiences merely thought out simply"; in other words, a series of operations performed in imagination. The results of these operations are also imagined and are assumed as the conclusions of the reasoning itself.
This conception of reasoning, which Rignano derived chiefly from Ernst Mach, was later applied by him to explain the various kinds of reasoning: intuition, reduction, mathematical and mathematico-logical reasoning, intentional reasoning (dialectical or metaphysical reasoning), and pathological forms of reasoning as well.
Rignano stressed the distinction between constructive and intentional reasoning. Constructive reasoning is motivated by a desire to discover the truth, and intentional reasoning by a desire to confirm a truth that a person believes he already possesses.
Both types of reasoning utilize the same syllogistic form, but constructive reasoning is characteristic of the positivist scientist and intentional reasoning of the metaphysician.
Rignano did not distinguish clearly between logical and psychological considerations; rather, he assumed the psychological mechanism as the basis of the logical validity of reasoning processes. The result is that Rignano's account is not very convincing either as logic or as psychology.
Despite his distaste for metaphysics, Rignano in subsequent works elaborated a kind of biological metaphysics based on the hypothesis that at the foundation of life and its evolution there is a "nervous energy" able to mold organic matter and direct it toward an increasing development and a growing adaptation to the environment.
According to Rignano, life in its entirety shows a finalistic aspect that would be inexplicable if it were the product of physicochemical forces. This finalism can be explained, however, by assuming that life is a product of psychic, mnemonic energy, which on the basis of past experience envisions ends of future experience and adapts organic material to those ends.
It is a kind of vitalism or animism that, according to Rignano, guarantees to evolution a progressive significance. The progress of evolution continues beyond organic life into moral life. The purpose of moral life is to guarantee to all individuals the satisfaction of their needs and to coordinate these needs in harmonious forms that gradually eliminate conflicts.