The philosopher who emphasized the importance of ideas and moral principles in shaping society, as opposed to the material base of society emphasized by Karl Marx, is (B) Max Weber.
Karl Marx is known for his focus on the material conditions and economic factors as the primary influences on society. He believed that the economic base, primarily composed of the means of production and labor relations, fundamentally shaped the superstructure, which includes culture, politics, and ideology.
Max Weber, on the other hand, introduced a different perspective. While he acknowledged the importance of economic factors, Weber argued that ideas, values, and beliefs play a crucial role in shaping society. He is well-known for his thesis in 'The Protestant Ethic and the Spirit of Capitalism,' where he proposed that the religious ideas of Protestantism, especially Calvinism, were instrumental in the development of capitalist societies. He believed that ideas and moral principles could lead to social change and had a significant influence on social structures.
Therefore, the correct answer is (B) Max Weber, as he emphasized the significance of ideas and moral principles in shaping society, complementing Marx's focus on material conditions and structures.