To the general idea of Karl Marx, Loria adds a theory about "the occupation of free land," which is the fundamental cause of the technical explanation of the different econo-micro-social organizations, a theory which he has amply demonstrated in his _Analisi della proprieta capitalistica_, Turin, 1892. [80] It is seen what our judgment must be regarding the thesis maintained by Ziegler, in his book: _La question sociale est une question morale_ (The social question is a moral question). French trans., Paris, 1894. Just as psychology is an effect of physiology, so the moral phenomena are effects of the economic facts. Such books are only intended, more or less consciously, to divert attention from the vital point of the question, which is that formulated by Karl Marx. See on our side, DE GREEF, _l'Empirieme, l'utopie et le socialisme scientifique_, Revue Socialiste, Aug., 1886, p. 688. [81] As proof of that conspiracy of silence about the theories of Karl Marx, it suffices for me to point out that the historians of socialism generally mention only the technical theory of _surplus-labor_, and ignore the two other laws: (1) the determination of social phenomena and institutions by economic conditions, and (2) the Class Struggle. [82] The votes on measures imposing taxes in the legislative bodies of all countries afford obvious illustrations of this principle. (The alignment of forces in the struggle for the income tax under the late administration of President Cleveland, is a very striking instance.--Tr.) [83] If _uncompromisingness_ was an English word, it would express the thought more clearly and strongly.--Tr. [84] Parties related by affinity of object, tactics, or, more especially, of immediate demands.--Tr. [85] See the lectures of DE AMICIS. _Osservazioni sulla questione sociale_, Lecce, 1894. LABRIOLA, _Il Socialismo_, Rome, 1890. G. OGGERO, _Il Socialismo_, 2nd edition, Milan, 1894. [86] There are, however, certain forms of this mysticism which appeal to our sympathies very strongly. Such forms I will call _social mysticism_. We may instance the works of Tolstoi, who envelops his socialism with the doctrine of "non-resistance to evil by violent means," drawn from the _Sermon on the Mount_. Tolstoi is also an eloquent _anti-militarist_, and I am pleased to see quoted in his book _le Salut est en vous_, Paris, 1894, a passage from one of my lectures against war. But he maintains a position aloof from contemporary experimental science, and his work thus fails to reach the mark. APPENDIX I[87] Editor, etc. DEAR SIR:- I have read in your journal a letter from Mr. Herbert Spencer in which he, relying on indirect information conveyed to him, regarding my book, _Socialism and Modern Science_, expresses "his astonishment at the audacity of him who has made use _of his name_ to defend socialism."