What is Marx's view on the origin and development of reason in the human world?
I think that the mere concept of "reason" in terms of its development and origin has to be examined. If one is examining the concept of reason that enabled capitalism to take a hold of the world's economic condition, Marx and Engels would argue that its origin and development was constructed by those in the position of economic power to ensure their own hold over the means of production. Marx would argue that the liberal economists who argued that it was reasonable to embrace the marketplace and that rational thought guided and substantiated capitalism failed to understand or deliberately ignored that challenges posed to majority of the people under capitalism. The massive proliferation of capitalism and the cyclical conditions of hardship that would become evident to so many could not be seen as "reasonable" under any standard for Marx and Engels. It is in this where the origin and development of reason as a way to continue the capitalist system would be seen as a tool to consolidate control and ensure hardship to many at the hands of the economically privileged few.