What you tell me of the forthcoming second volume of Cosmos, makes me look forward to the study of it with impatience; you are not to be read, you must be studied, and the place of a pupil suits me exactly. No one is more called upon than I am to do justice to your remark relative to the influence exercised by Christianity on the natural sciences,[49] as upon mankind in general and hence upon all science, for that remark has long since dawned upon my mind. It is correct in all respects, and its generating cause is simple as are all other truths, those which are, as well as those which are not understood, for the latter circumstance has no effect on the substance of a truth. Error leads to error, as truth is the guide to truth. As long as the mind remained in error in the sphere of thought which is the most elevated of all those attainable by the human mind, this deplorable state of things could not fail to react upon every quarter of the moral compass upon all intellectual and social questions, and to oppose to their development in the right direction, an insurmountable obstacle. _The good news_ once told, the position could not but change. It was not by bestowing divine honor on _effects_ that they could be traced to the fountain head of truth; the investigation continued to be confined to the abstract speculations of the philosophers, and to the rhapsodies of poets. The _cause_ once laid bare, the hearts of men were comforted, and their minds opened to conviction. Nevertheless, the latter still remained for a long time shrouded in the mists of pagan scepticism, until at last scholastic philosophy was unhorsed by experimental science. Do you admit the force of my reasoning? If you do, I have no doubt you will share my fears that true scientific progress is in danger of being checked by too ambitious spirits, who desire to rise from the effects to the cause, and who finding the approach cut off by the impassable barriers which God has set upon human intelligence, and finding themselves unable to advance, roll back upon themselves, and relapse into the stupidity of paganism, in seeking the cause in the effect! The world, my dear Baron, is in a dangerous position. The social body is in fermentation. You would do me a great favor if you could teach me the nature of this fermentation, whether it is spirituous, acid, or putrid? I greatly fear that the _verdict_ will be for the last-named of these kinds, and it is not I who could teach you that these products are hardly beneficial. Be pleased to accept the thanks of my household for your friendly memento, and the assurance of the continuance of my old attachment. METTERNICH. 123. HUMBOLDT TO VARNHAGEN. BERLIN, _May 30th, 1846_.