莱布尼茨逻辑学说及其当代影响

莱布尼茨是最后一位经院逻辑学家，也是第一位现代逻辑学家。但传统的逻辑史家只注意到了他的第一个方面，而忽略甚至贬低他的第二个方面。事实上，莱布尼茨不仅创造了不同类型的亚里士多德逻辑形式系统，部分地预见了布尔的逻辑代数演算，而且还有极为丰富的命题逻辑思想，尤其是他的真性和道义模态命题逻辑在相当程度上预见了现代意义上的真性模态逻辑和道义模态逻辑，构成了现代逻辑早期发展的重要组成部分。从这种意义上讲，莱布尼茨既是亚里士多德逻辑学的集大成者，同时又是弗雷格现代逻辑的伟大先驱。

Leibniz's Theory of Logic and Its Contemporary Influence

Leibniz was the last schoolman and the first modern logician .He invented different types of formalization of Aristotelian logic which in parts anticipated George Boole's calculus .But the logic of Leibniz is assuredly that part of his system that has been most neglected by historians of philosophy and mathematics .Philosophers,understandably seduced by his metaphysics,have accorded little form it assumed .Mathematicians,on the other hand,have looked to Leibniz primarily as the inventor of the differential and integral calculus and have been engaged neither by his general theories on the value and importance of the mathematical method nor by his attempts at applying algebra to logic,which they have contemptuously dismissed as metaphysics .As a result,neither group has fully grasped the principles of his system,nor have they been able to reach the source from which both the infinitesimal calculus and the Monadology flow . There is,of course,the excuse that Leibniz's logical essays have been published only slowly and very incompletely .Even today they are scattered piecemeal among various partial editions,most notably the two in s which Gerhardt has so unfortunately separated the mathematical and philosophical writings . As if one could dissect the work of an encyclopedic savant whose philosophy was nourished by the study of all the sciences and in turn inspired all of his scientific discoveries .If there is a thinker whose thought cannot be divided with impunity in this way,it is certainly the one who said :″My metaphysics is entirely mathematical,″or again,″Mathematicians have as much need to be philosophers as philosophers have to be mathematicians .″This artificial and arbitrary division between contemporaneous works that mutually depend on and illuminate one another has had the result of concealing the unity of the system and of hiding its true principles . Thus the absurd and deplorable schism between letters and sciences not only compromises the future of philosophy,but also falsifies its history and renders its past unintelligible by isolating it from the scientific speculations where it has always taken root .One sees readily that Leibniz's philosophy was bound to suffer more than any other,and within this philosophy his logic,precisely because it is the center of,and the link between,his metaphysical speculations and his mathematical inventions .