Before assessing the impact of evolutionary theory on Galdós's understanding of Spain's perceived moral and spiritual deficit, it is pertinent to take an overview of contemporary society's preoccupation with this problem. One important source of evidence in this area stems from nineteenth-century Spain's self-examination, and in particular its reflection on a glorious past which had given way to a mediocre present. Darwin's hypothesis about Spain's decline as a nation in The Descent of Man could only serve to compound a pre-existing inferiority complex:

Darwin offers reasons for Spain's relatively poor levels of trade, empire building and cultural advancement. Of particular concern to many Spaniards was their lamentable record in the natural sciences, frequently used as the yardstick by which they could measure their perceived failure as a modern nation. In light of these preoccupations it is not difficult to see why a re-examination of the nation's past achievements would become such a pressing concern for contemporary Spain.

An influential voice of the era in Spain belonged to Joaquín Costa, with whom Galdós was well-acquainted. As epistolary records in the Casa-Museo Pérez Galdós confirm, by the late 1890s Galdós was reading and editing Costa's proofs prior to publication. Experimental science was central to Costa's thinking, his Política hidráulica being perhaps the most obvious example.