Marxism has defined its key values in opposition to animals other than human in order to promote the interests of the most downtrodden human beings. Although it has characterized itself as a scientific historical and economic theory, sympathy for human suffering has provided its most powerful motivation as a political force. This capacity for sympathy, causing in modern times an extension of Marxist concerns beyond "class" in the original sense, is beginning to accommodate animals as are the theoretical concepts of alienation, surplus value, and historical materialism. Marxism's inconsistencies are being resolved in favor of the side that, for human as well as animal benefit, favors individual sentience and other pro-animal values. So, in a truly dialectical progression, the same quality of sympathy that at first caused Marxism to denigrate animals is now coming out in their support.