The essay can also be interpreted as one of Weber's criticism of Karl Marx and his theories. While Marx's historical materialism held that all human institutions – including religion – were based on economic foundations, many have seen The Protestant Ethic as turning this theory on its head by implying that a religious movement fostered capitalism, not the other way around.
Other scholars have taken a more nuanced view of Weber's argument. Weber states in the closing of this essay, "it is, of course, not my aim to substitute for a one-sided materialistic an equally one-sided spiritualistic causal interpretation of culture and history. Each is equally possible, but each if it does not serve as the preparation, but as the conclusion of an investigation, accomplishes equally little in the interest of historical truth." Weber's argument can be understood as an attempt to deepen the understanding of the cultural origins of capitalism, which does not exclude the historical materialist origins described by Marx: modern capitalism emerged from an elective affinity of 'material' and 'ideal' factors.[2]
