Answer
Empirio-monism, a key point of contention between Lenin and Bogdanov, was a philosophical viewpoint that emphasized the role of experience in understanding reality by synthesizing elements of empiricism and monism. Lenin criticized this approach, arguing that it undermined the materialist basis of Marxism and led to subjective interpretations. This philosophical divide contributed to the broader ideological and political differences that emerged within the Bolshevik party during the early 20th century.