The most popular of the Marxian teachings is the doctrine of the irreconcilable conflict of social classes.
Status or Caste in Precapitalistic Society↩
In the precapitalistic ages the characteristic mark of society’s organization was status. In the status or caste society there prevail legal differences among individuals. The individual’s station in life was fixed by his status. He inherited from his parents at birth his caste membership and his position in life was rigidly determined by the laws and customs that assigned to each member of his rank definite privileges, duties, and disabilities. Exceptional good or bad luck might in some rare cases elevate an individual into a higher rank or debase him into a lower rank. But as a rule, the conditions of the individual members of a definite order or rank could improve or deteriorate only with a change in the conditions of the whole membership. The individual was primarily not a citizen of a nation; he was a member of an estate (Stand in German, état in French).
This system, that in England had already been substantially tempered and humanized in the Middle Ages, is incompatible with the capitalistic methods of the market economy. It was finally abolished in the countries of the European continent by the French Revolution and by the revolutions and reforms which the French Revolution called forth. Its last vestiges in the capitalistic part of the world disappeared when slavery was abolished step-by-step in the Americas and in the overseas colonies of the European powers.
In the status society there prevails, on the one hand, a solidarity of interests of all members of the same caste and, on the other hand, an irreconcilable conflict of interests between the members of different castes. All slaves, for instance, are united in having a stake in the abolition of slavery while their masters are opposed. All members of the European nobility were opposed to the abolition of their tax exemption, from which the Third Estate people expected a relaxation of their own burden. But no such conflicts are present in a society in which all citizens are equal before the law. No logical objection can be advanced against distinguishing various classes among the members of such a society; any classification is logically permissible, however arbitrarily the mark of distinction may be chosen. But it is nonsensical to classify the members of a capitalistic society according to their position in the framework of the social division of labor and then to identify these “classes” with the castes of a status society. It is precisely this that the Marxian doctrine of the irreconcilable struggle of classes does.
The “classes” that Marx distinguishes within a capitalistic society have a continually fluctuating membership. Class affiliation under capitalism is not a hereditary quality. It is assigned to each individual by a daily repeated plebiscite, as it were, of all the people. The buying public, the consumers, by their buying and abstention from buying, determine who should own and run the plants, who should work in the factories and mines, who should play the parts in the theater performances, and who should write the newspaper articles. They do it in a similar way in which they determine in their capacity as voters who should act as president, governor, or judge. In order to get rich in a capitalistic society and to preserve one’s once-acquired wealth one must satisfy the wishes of the public. Those who have acquired wealth as well as their heirs must try to keep it by defending their assets against the competition of already established firms and of ambitious newcomers. In the unhampered market economy, not sabotaged by concessions and exemptions accorded to powerful pressure groups, there are no privileges, no protection of vested interests, no barriers preventing anybody from striving after any prize. Access to the Marxian-designated classes is free to everybody. The members of each class compete with one another. They are not united  by a common class interest and not opposed to the members of other classes by being allied either in the defense of a common privilege, which those wronged by it want to see abolished, or in the attempt to abolish a legal disability which those deriving advantage from it want to preserve.
The champions of modern political freedom and laissez faire asserted: If the old laws establishing status privileges and disabilities are abolished and no new practices of the same character—such as subsidies, discriminatory taxation, indulgence granted to nongovernmental agencies like unions to use coercion and intimidation—are introduced, there is equality of all citizens under the law. Nobody is hampered in his aspirations and ambitions by any legal obstacles. Everybody is free to compete for any social position or function for which his personal abilities qualify him.
But Marx saw things in a different light. He maintained that capitalism did not abolish bondage and did not do away with the servitude of the working and toiling masses. It did not emancipate the common man. The people merely changed their masters. Formerly they were forced to drudge for the princes and aristocrats; now they are exploited by the bourgeoisie. The division of society into “social classes” is, in the eyes of Marx, sociologically and economically not different from its division into the castes of the status society. The bourgeois of the modern age is no less a predatory extortioner than were the noblemen and slaveholders of ages gone by.
But what characterizes the “social class” as such, and what entitles us to equate it with the castes of the status society? To this question Marx never gave an answer. All his books, pamphlets, and writings turn around the concept of the social class and the essence of his political and economic program is the abolition of “social classes” and the establishment of what he styles a classless society. But he never told us what he had in mind when employing the term “social class” and what justifies ascribing to the division of society into “social classes” the same effects as its division into castes had.
The main treatise of Karl Marx is Das Kapital. It was designed to provide a scientific justification of the ideas Marx had expressed in his numerous pamphlets and manifestos. Only the first volume of this book was published by Marx himself in 1867. Two years after the death of Marx his friend Engels published the second volume and finally, in 1894, eleven years after the death of Marx, the third volume, which consists of  two parts, 870 pages altogether. Yet, the book remained unfinished. The third volume contains fifty-one chapters; then follows a fifty-second one-page chapter that is headed “The Classes.” There Marx declares that the first question to be answered is what constitutes a class. But he does not provide an answer. Instead we read a note by the editor, Engels, saying: Here the manuscript breaks off.
One could be tempted to say: It is really tragic. Here is an author to whom fate denied the opportunity to define and to explain the fundamental concept of his philosophy, the concept on which all he said, argued, and planned depended. At the hour in which he was to write down the most important thing he had to tell mankind, death took him off. How lamentable!
But a closer inspection reveals a different aspect of the case. The abundant biographical material about Marx collected and published by his followers and the Marx-Engels-Lenin Institute in Moscow evinces the fact that Marx had ceased to work on his book many years before his death. There cannot be any doubt about the reason. When faced with the task of telling in precise words what he had in mind when perorating about “social classes” and giving reasons for his doctrine of the irreconcilable conflict of interests between the “social classes,” Marx failed thoroughly. He had to acknowledge to himself that he was perplexed and was at his wit’s end. He did not know what to say in the planned fifty-second chapter of the third volume and this embarrassment induced him to desist from finishing his great treatise. The essential dogma of the Marxian philosophy, the class conflict doctrine which he and his friend Engels had propagated for many decades, was unmasked as a flop.
Marxian Ideology Doctrine↩
The only retort that Marx, Engels, and all their followers down to the Russian Bolshevists and the European and American professorial admirers of Marx knew to advance against their critics was the notorious ideology doctrine. According to this makeshift a man’s intellectual horizon is fully determined by his class affiliation. The individual is constitutionally unfit to reach out and to grasp any other doctrine than one that furthers the interests of his own “class” at the expense of other “classes.” It is, therefore, unnecessary for a proletarian to pay any attention to whatever bourgeois authors may say and to waste time refuting their  statements. All that is needed is to unmask their bourgeois background. That settles the matter.
This is the method to which Marx and Engels and later Marxians resorted in dealing with all dissenters. They never embarked upon the hopeless task of defending their self-contradictory system against devastating criticism. All they did was to call their opponents stupid bourgeois and to ascribe their opposition to their bourgeois class affiliation.
But Marx and Engels also contradicted their own doctrine in this regard. They both were scions of bourgeois families, brought up and living in a typical middle-class milieu. Marx was the son of a well-to-do member of the bar and married the daughter of a Prussian nobleman. His brother-in-law was Cabinet Minister of the Interior and as such the Chief of the Royal Prussian Police. Engels was the son of a wealthy manufacturer and a rich businessman himself; he indulged in the amusements of the British gentry such as riding to hounds in a red coat, and snobbishly refused to marry his mistress because she was of low origin. From the very Marxian point of view one would have to qualify Marxism as a doctrine of bourgeois origin.
The Destruction of Marxian Ideas Demands Vigorous Criticism↩
The enormous power that the Marxian ideas and the political parties guided by them enjoy in the present is not due to any inherent merits of the doctrine. It is an outgrowth of the moral and intellectual indifference and apathy of those whose duty it ought to be to offer unswerving resistance to false doctrines and to disclose their untruth. Some eminent philosophers and economists have provided irrefutable arguments to show the perversion, the misrepresentation of facts, and the self-contradictions of the Marxian creed. But their books are not read by those whose responsibility it is to enlighten the public. Thus the masses today indolently endorse all the socialist slogans and look upon every step forward on the way toward totalitarianism as progress toward the establishment of an earthly paradise. It is the inertness and sloth on the part of many of our most eminent fellow citizens that make the impetuous advance of the communist power possible.
The task of fighting Marxian dialectical materialism and all the various epistemological, philosophical, economic, and political doctrines emanating from it can only be accomplished by well-informed people. Those who want to contribute seriously to the defense of Western  civilization against the onslaught of the dictators must acquaint themselves with the doctrines they plan to fight and must with full vigor study the writings of those authors who have long since entirely demolished all the Marxian fables and distortions. One has to admit that this is not an easy matter. Yet, there are in this world no great things that can be accomplished but by moral resolution and strenuous exertion.
Economic Freedom and Intervention, pp. 136-141, Ludwig von Mises