One of the few things modern liberals, classical liberals, and conservatives can agree on is the charge that some of the worst features oftotalitarian socialist regimes have their origins in the writings of Karl Marx and Friedrich Engels. Nevertheless, the nature of this claim, and therefore the reasons for accepting or rejecting it, are oftenleft obscure.
If it is understood simply as a causal statement, then it must be confirmed or disconfirmed by empirical social science. The political philosopher can at most assist by providing a clear characterization of the conceptual content of the beliefs which constitute the independent variable in the alleged causal relation: those beliefs concerning Marx's and Engels's thoughts which are said to have exerted the causal influence in question. Even if empirical research did showthat beliefs about Marxist theory were a significant causal influencein the rise of certain features of totalitarian socialism, this wouldbe of limited philosophical interest if the beliefs in question were misunderstandings of the theory and if the correct explanationof why these misunderstandings occurred appealed to factors external to the theory itself. However, it would be of considerable philosophical interest if correct beliefs about Marxist theory exerted a causalinfluence on some of the more undesirable aspects of totalitarian socialism, or if incorrect beliefs did and the existence of thesemisunderstandings could be traced to ambiguities or gaps in the Marxist theory itself. The political philosopher has a legitimate interestin the relationship between the writings of Marx and Engels on the rise of totalitarian socialism, not because he is interested in articulating and testing causal connections between beliefs and social phenomena in general, but because Marxist theory is supposed – by its authors – to inspire and guide change toward a better society.