Mistakes of Marx and Engels In the fields of philosophy, history, politics, and economics, Karl Marx and Friedrich Engels made many mistakes. Without conducting their own independent research, they depended on the research and ideas of others and developed arguments, analyses, conclusions, and programs based on them. This may be called dependent psychology. In other words, they made decisions based on second-hand information and formulated programs accordingly. The knowledge obtained through books is indirect knowledge, not direct knowledge. https://www.boloji.com/articles/55317/mistakes-of-marx-and-engels