Following a line of discourse which is neither exclusively historicophilological nor freely theoretical, I intend to show how the 193 0s saw two different and yet partly convergent attempts to devise not so much, or not primarily, a philosophy of science but a scientific philosophy. In order to do this, I will compare, in the first two sections, some relevant aspects of the "philosophical itineraries' of Moritz Schlick and Giulio Preti. I will illustrate these itineraries by putting them in relation both with some of Kant's, Husserl's and Cassirer's ideas, and with other relevant aspects of the development of logical empiricism in Carnap, Reichenbach and Neurath. In the third section, I will then take into consideration the question of scientific explanation, in the terms in which Wesley C. Salmon gradually came to approach it in the course of more than thirty year long research, and try to show how this set of problems, which belongs more specifically to the philosophy of science came to intersect with the set of typically epistemological problems discussed by Schlick and Preti.