Final answer:
The characterization of Nastasya and Raskolnikov reflects a naturalistic theme exploring the deterministic struggles of individuals within society, influenced by the literary and historical context of 19th century Russia.
Step-by-step explanation:
The characterization of Nastasya and Raskolnikov in Fyodor Dostoevsky's novel suggests a theme of naturalistic struggles between the individual and society, and a deeper exploration into the human condition. The Naturalist movement in literature, which Dostoevsky's work often embodies, portrays characters as influenced by their environments and hereditary traits, suggesting a deterministic universe. This thematic expression aligns with the broader Russian literature of the time, which grappled with the country's political turmoil, the confines of intellectual society, and a search for the Russian 'soul.' Characters like Nastasya and Raskolnikov are deeply reflective of the social conditions of 19th century Russia, struggling with their internal conflicts amidst a harsh and indifferent world, indicating a loss of free will and a descent into potential degeneration.