i8qi -1 The Future of Systematic Botaiiy. 253 



was to simplify the whole scheme of plant arrangement. This 

 tendency may have soon been checked by wise friends or sad 

 experience, but to attack the largest problems first is as natu- 

 ral as youth itself. I speak of this, not only as a generaliza- 

 tion, but also as a reminiscence. 



But these Phaeton-like attempts aside, wherein lies the 

 necessity of this most difficult work before the facts are all 

 *n, this attempting what is conceded to be impossible? Is it 

 of any advantage to construct a system to-day which must be 

 found faulty to-morrow ? It is of the highest advantage to 

 construct any system which shall embody every known fact 

 concerning affinity. Every such system becomes, as ought to 

 be clearly understood, simply an expression of our imperfect 

 knowledge, a convenient summary of information, a sort of 

 mile-post to tell us how far we have come, and to direct future 

 effort. In his essay upon <4 The Significance of Sexual Repro- 

 duction in the Theory of Natural Selection," Weismann uses 

 these words, which are well worth quoting in this connection : 



" Instead of comparing the progress of science to a building, I should prefer 

 to compare it to a mining operation, undertaken in order to open a freely 

 branching lode. Such a lode must not be attacked from one point alone, but 

 from many points simultaneously. From some of these we should quickly 

 reach the deep-seated parts of the lode, from others we should only reach its 

 superficial parts ; but from every point some knowledge of the tout ensemble of 

 the lode would be gained. And the more numerous the points of attack, the 

 roore complete would be the knowledge acquired, for valuable insight will be ob- 

 tained in every place where the work is carried on with discretion and persever- 

 ance. But discretion is indispensable for a fruitful result; or. leaving our 

 metaphor, facts must be connected together by theories, if science is to advance. 

 Just as theories are valueless without a firm basis of facts, so the mere collec- 

 tion of facts, without relation and without coherence, is utterly valueless. 

 Science is impossible without hypotheses and theories ; they are the plummets 

 with which we test the depth of the ocean of unknown phenomena, and thus 

 determine the future course to be pursued on our voyage of discovery. They 

 do not give us absolute knowledge, but they afford us as much insight it is pos- 

 sible for us to gain at the present time. To go on investigating, without the 

 .guidance of theories, is like attempting to walk in a thick mist without a com- 

 pass. We should get somewhere under these circumstances, but chance alone 

 would determine whether we should reach a stony desert of unintelligible facts or 

 a system of roads leading in some useful direction ; and in most cases chance 

 would decide against us." 



It becomes very evident that the work oi constructing even 

 a Natural System which must be tentative, a sort of tempo- 

 rary scaffold, is one which demands not only the widest ran; 1 

 °f information (and hence a task which is daily becoming 

 i^ore exacting), but also that broad grasp in generalization 

 which is possessed by very few. The marshaling of facts is 

 •ike the marshaling of armies, and very few are born generals. 

 Almost any one can arrange the plant kingdom who is pos- 



