Communism is the most
logical and extreme form of Socialism, outcome of the revolutionary
theory of Karl Marx. The underlying philosophy is materialistic and
determinist; the social order evolves through economic struggles
between the classes in the direction of the violent revolution and a
dictatorship of the proletariat, to be followed by a "withering
away" of the state and the substitution of a society where ownership
of all things is common, where all will work voluntarily, and all
take freely of goods produced according to his needs. As well
as the abstract theory of Communism there must, since 1917, be
considered the concrete attempt to apply its principals in the Union
of Soviet Socialist Republics, where one aspect of it can be summed
up in the words of Stalin: "Scientifically speaking, the
dictatorship of the proletariat is a power which is restricted by no
laws, hampered by no rules, and based directly on violence."
Whether in theory or in practice, the Church utterly rejects Communism on account of its errors, notably: its atheistic materialism, its doctrine and practice of class-war, its denial of the rights and liberties of the human person, including the natural right to possess some measure of private property, and its contempt for good morals under several heads.
Communism has been repeatedly condemned by the Holy See, notably by Pope Pius XI in the encyclical letter, Divini Redemptoris .
Historical materialism goes on and says: the rising bourgeoisie within feudalism, through the furtherance of its own material interests, captured power and abolished, of all relations of private property, only the feudal privileges and with this took out of existence the feudal ruling class. This was another of the keys behind the consolidation of capitalism as the new mode of production, which is the final expression of class and property relations and also has led into a massive expansion of production. It is therefore only in capitalism that private property in itself can be abolished.  Similarly, the proletariat will capture political power, abolish bourgeois property through the common ownership of the means of production, therefore abolishing the bourgeoisie and ultimately abolishing the proletariat itself and ushering the world into a new mode of production: communism. In between capitalism and communism there is the dictatorship of the proletariat , a democratic state where the whole of the public authority is elected and recallable under the basis of universal suffrage .  It is the defeat of the bourgeois state, but not yet of the capitalist mode of production and at the same time the only element which places into the realm of possibility moving on from this mode of production.