I should also like to call Labriola's attention to another confusion, very common in Marxian writings, between _economic forms of organisation_ and _economic epochs_. Under the influence of evolutionist positivism, those divisions which Marx expressed in general: the _Asiatic_, the _antique_, the _feudal_ and the _bourgeois_ economic organisation, have become four historical _epochs_: _communism_, _slave organisation_, _serf organisation_, and _wage-earning organisation_. But the modern historian, who is indeed not such a superficial person as the ordinary Marxians are accustomed to say, thus sparing themselves the trouble of taking a share in his laborious procedure, is well aware that there are four _forms_ of economic organisation, which succeed and intersect one another in actual history, often forming the oddest mixtures and sequences. He recognises an Egyptian mediævalism or feudalism, as he recognises an Hellenic mediævalism or feudalism; he knows too of a German _neo-mediævalism_ which followed the flourishing bourgeois organisation of the German cities before the Reformation and the discovery of the New World; and he willingly compares the general economic conditions of the Greco-Roman world at its zenith with those of Europe in the sixteenth and seventeenth centuries. Connected with this arbitrary conception of historical epochs, is the other of the inquiry into _the cause_ (note carefully; into the cause) of the transition from one form to another. Inquiry is made, for instance, into the _cause_ of the abolition of slavery, which must be the _same_, whether we are considering the decline of the Greco-Roman world or modern America; and so for serfdom, and for primitive communism and the capitalist system: amongst ourselves the famous Loria has occupied himself with these absurd investigations, the perpetual revelation of a single cause, of which he himself does not know exactly whether it be the earth, or population or something else--yet it should not take much to convince us, (it would suffice for the purpose to read, with a little care, some books of narrative history), that the transition from one form of economic, or more generally, social, organisation, to another, is not the result of a _single cause_, nor even of _a group of causes which are always the same_; but is due to causes and circumstances which need examination for each case since they usually vary for each case. Death is death; but people die of many diseases. But enough of this; and I may be allowed to conclude this paragraph by reference to a question which Labriola also brings forward in his recent work, and which he connects with the criticism of historical materialism.