The struggle for the triumph of truth, in which I have had the most curious experiences during the last forty years, has brought me a number of new impressions through my Berlin lectures. The flood of calumnies of all kinds that the religious press (especially the Lutheran _Reichsbote_ and the Catholic _Germania_) poured over me exceeded any that had gone before. Dr. Schmidt gave a selection from them in the _Freie Wort_ (No. 4, p. 144). I have already pointed out, in the Appendix to the popular edition of the _Riddle of the Universe_ [German edition], what unworthy means are employed by my clerical and metaphysical opponents for the purpose of bringing my popular scientific works into disrepute. I can only repeat here that the calumniation of my person does not move me, and does not injure the cause of truth which I serve. It is just this unusually loud alarm of my clerical enemies that tells me my sacrifices have not been in vain, and that I have put the modest key-stone to the work of my life--"The advancement of knowledge by the spread of the idea of evolution." THE END _Printed by Cowan & Co., Limited, Perth._ FOOTNOTES: [1] The word "evolution" is still used in so many different ways in various sciences that it is important to fix it in the general significance which we here give it. By "evolution," in the widest sense, I understand the unceasing "mutations of substance," adopting Spinoza's fundamental conception of substance; it unites inseparably in itself "matter and force (or energy)," or "nature and mind" (= the world and God). Hence the science of evolution in its broader range is "the history of substance," which postulates the general validity of "the law of substance." In the latter are combined "the law of the constancy of matter" (Lavoisier, 1789) and "the law of the conservation of energy" (Robert Mayer, 1842), however varied may be the changes of _form_ of these elements in the world-process. _Cf._ Chapter XII. of _The Riddle_. [2] Certain orthodox periodicals have lately endeavoured to deny this famous atheistical confession of the great Laplace, which was merely a candid deduction of his splendid cosmic system. They say that this Monistic natural philosopher acknowledged the Catholic faith on his death-bed; and in proof of this they offer us the later testimony of an Ultramontane priest. We need not point out how uncertain is the love of truth of these heated partisans. When testimony of this kind tends to "the good of religion" (_i.e._, their own good), it is held to be a pious work (_pia fraus_). On the other hand, it is interesting to recall the reply of a Prussian Minister of Religion, Von Zedlitz, 120 years ago, to the Breslau Consistory, when it urged that "those who believe most are the best subjects." He wrote in reply: "His majesty [Frederick the Great] is not disposed to rest the security of his State on the stupidity of his subjects."