Final answer:
Both classical and modern liberalism have an optimistic view of human nature based on the power of reason and rationality, believing that humans can make progress and govern themselves effectively.
Step-by-step explanation:
Both classical liberalism and modern liberalism indeed share an optimistic view of human nature, but the basis of their optimism differs somewhat between the two philosophies. Classical liberals, hailing from the tradition established by thinkers such as John Locke, believe in innate natural rights, limited government, and capitalism. Central to classical liberalism is a belief in individual liberties and rights, mainly supported by the idea of free will and the notion that people are born equal and have the right to make decisions for themselves without undue government intervention.
Modern liberalism evolves from these principles to focus on equality, supporting government intervention where it promotes such equality and enables everyone to have the opportunity for success. This view aligns with social contract theories and the Enlightenment values, which emphasize the power of reason and rationality in human affairs. Thinkers like John Rawls have further refined liberal thought to focus on opportunities for individuals to realize their full potential.
Therefore, an optimistic view of human nature in both classical and modern liberal thought is fundamentally based on B) The belief in the power of reason and rationality. This belief holds that humans can use their reason to progress society, make moral and rational decisions, and govern themselves effectively with minimal interference from others, particularly the state.