TEE LIBERTY OF SCIENCE IN TEE MODERN STATE. 



297 



may hope to retain securely for the future the 

 possession which we actually enjoy. The fact 

 that we are enabled to discuss, as we do to-day, 

 is not for one who, like myself, has had long ex- 

 perience of public life, a sufficient assurance that 

 it will always remain so. Therefore, I think that 

 not only should we strive to awaken the interest 

 of the public, but I believe we should ask our- 

 selves what we must do to maintain the present 

 condition of things. I will tell you at once, gen- 

 tlemen, what I conceive to be the chief result of 

 my reflections, and what I most desire to prove. 

 I wish to show that, for the present, we have 

 nothing more to ask, but that, on the contrary, 

 we have now reached the point where it must 

 needs be our special task, by our moderation, 

 and by a certain renunciation of pet theories and 

 personal views, to make it possible for the favor- 

 able disposition of the nation, which we now en- 

 joy, to persist and not to change to the contrary. 

 In my opinion, we are actually in danger of 

 compromising the future by making too ample 

 use of the freedom afforded by the present state 

 of things ; and I would warn you against indulg- 

 ing such caprices of personal speculation as you 

 see nowadays displayed in sundry departments of 

 natural science. The discourses of those who 

 have preceded me, that of Prof. Nageli in particu- 

 lar, contain, for all who read them, a multitude 

 of highly-important observations on the course 

 and the limits of scientific knowledge ; but these 

 it cannot be my task to repeat here. Still, I 

 have some remarks to make about them, and I 

 desire to adduce a few practical instances from 

 the experience of natural science, in order to 

 show how great is the difference between real 

 science in the strictest sense of that term — for 

 which alone, in my opinion, we can justly demand 

 that full measure of liberty which may be called 

 liberty of science, or, more correctly still, per- 

 haps, liberty of scientific teaching — and, on the 

 other hand, that wider domain which belongs 

 rather to speculation ; which raises the problems 

 toward which research is to be directed ; which 

 by anticipation formulates propositions that have 

 yet to be demonstrated, and whose truth has 

 yet to be discovered, though in the mean time 

 they may be with a certain probability accepted, 

 inasmuch as they fill up gaps in our knowl- 

 edge. We must not forget that there exists a 

 line of demarkation in natural science between 

 what is speculative and what is actually proved 

 and ultimately determined. The people demand 

 of us that this line not only should be on occasion 

 drawn as clearly as possible, but that it be so 



fixed and determined that every one shall for ever- 

 more know just where it lies, and how far he can 

 be required to accept as truth what he is taught. 

 Such, gentlemen, is the task on which we have to 

 work in our own minds. 



The practical questions which are connected 

 with this lie very near. It is evident that, for 

 whatever we consider to be assured scientific truth, 

 we must demand complete admission into the 

 scientific treasury of the nation. This the nation 

 must lake to itself — it must consume and digest it, 

 and continue to work at it. Herein lies the 

 double advantage which natural science offers to 

 the nation : on the one hand the material progress, 

 that enormous progress which has been made in 

 modern times. All the benefits derived from the 

 steam-engine, telegraphy, photography, etc. ; all 

 our discoveries in chemistry and the production 

 of dyestuffs, etc. — all rest essentially on the fact 

 that we men of science establish firmly certain 

 propositions, and when these have been fully 

 demonstrated, so that we know them to be scien- 

 tific truth, we give them to the nation at large ; 

 then others, too, can work with them, and create 

 new products, before unthought of, which come 

 into the world as perfect novelties, and which 

 transform the condition of society and of nations. 

 All this constitutes the material importance of 

 our labors. Their intellectual value is of like 

 importance. If I present the nation with a scien- 

 tific truth that is fully demonstrated, to which not 

 the least doubt attaches ; if I ask every one to 

 convince himself of the correctness of this truth, 

 to assimilate it, to make it part of his own 

 thoughts, of course I assume that his conception 

 of things in general will be similarly affected. 

 Every essentially new truth of this kind must 

 needs influence a man's whole mode of viewing 

 things, his method of thinking. 



If, for instance, to cite a ease that lies near, 

 we consider the advances made during the past 

 few years in our knowledge of the human eye, 

 beginning at the time when the several com- 

 ponent parts of the eye were first anatomically 

 separated, when these several anatomically sepa- 

 rated parts were first examined microscopically 

 and their respective structures determined, down 

 to the time when we gradually learned the vital 

 properties and the physiological functions of the 

 different parts, until at last, by the discovery of the 

 retina-purple (Sehpurpur), and its photographic 

 properties, an advance was made of which but 

 a year ago we hardly had an idea — then it is 

 evident that with each progressive step of this 

 kind some department of optics, particularly the 



