逻辑是哲学的一个核心部分，也是哲学中比较微妙费解的部分。今天有很多人以为逻辑就是形式逻辑加数理逻辑，那是一种误解。这个误解有两方面的问题，首先逻辑严格的说，数理是形式逻辑的延伸，是用符号来表达形式逻辑（所以数理逻辑也叫符号逻辑）。尽管与亚里士多德甚或康德时代的形式逻辑相比，今天的数理逻辑所涵盖的内容更多一些，但是从哲学的角度，我们完全可以把这种现象分作两部分来看，第一部分是对于形式逻辑的本质的描述的细化（或发展），第二部分是对这细化了的形式逻辑进行符号表达。所以把逻辑说成是形式逻辑加数理逻辑就有点象把中国说成是华夏之邦加北京；第二，逻辑是一个涵义很广的概念，它所涵盖的并不局限于形式逻辑或数理逻辑所表达的范围，本文接下来要节选翻译介绍的被称为形式逻辑大师的康德的划时代的名著《纯理性思维的评判》（Critique of Pure Reason）一书中的几个段落就清楚地表明了这一点。本文的翻译是基于该书的英译版（本人不懂德文），所以本人只对英译中这部分负责J，如果有朋友认为原英译版（附在本文后面）有不妥之处，也欢迎给指出来。

当然，今天人类文明对于逻辑的认识比起康德时代应该已有很大进步，不过我们也可以非常惊奇地发现其实康德的心目已经具有今天我们对于逻辑的认识的发展的很多雏形，甚至连我在本博客第一个提出的感性逻辑的雏形都在他的逻辑中隐约可见。不过，人类文明发展的一个奇怪的现象，那就是包括学术巨星在内的世人们看问题时常常好象有偏视的习惯。今天人们一提到康德就说到他的形式逻辑，就好象他从未对逻辑进行过如本文将要节选介绍的剖析一样，以致今天哲学界的人们都会说出“逻辑就是形式逻辑加数理逻辑”这样的话。

康德《纯理性思维的评判》共八章，第一章为“引言”，第二章为“美学”，第三章为“概念分析”，第四章为“原理分析”，第五章为“辩证法：谬误推理”，第六章为“辩证法：矛盾”，第七章为“辩证法：理想”，第八章为“方法的教义”。本文所介绍的段落选自该书的第三章。具体内容如下：

一．一般意义上的逻辑

我们的知识来源于智力的两个方面；第一个是接受客观存在的表现的能力（感受性或印象），第二个是透过这些表现来认识对象的能力（ [自发产生] 概念的自发性）。第一个能力使我们能够感受到客观存在，而第二个能力使我们能对对象进行思考（这是一种纯粹由智力所决定的结果）。所以，直觉与概念共同构成了我们所有知识的基本元素，也就是说光有概念没有直觉或光有直觉而没有概念都无法产生知识。两者都既可以是纯粹的也可以是经验的。当他们含有感性（这里要假定有实际对象的存在）的时候，他们属于是经验的。当不存在感性与对象的表现之间的交融的时候，他们是纯粹的。感性可以被称之为可感受的知识的材料。所以，纯粹的直觉只含有所直觉到的对象的形式，而纯粹的概念只含有对于所思考的对象的一般形式。纯粹的直觉或纯粹的概念是可以先于经验而存在的，与之相对的是经验的直觉和经验的概念。

如果我们的智力对客观对象的表现的接收可被称为感受性，那么智力的从它自己来产生存在的表现的能力（即前面提到的自发地产生知识的能力---博主注），应该被称为理解。我们的本性使得我们的直觉一定是感性的；也就是说，它只含有客观存在对我们所发生的直接作用。另一方面，我们对于感性直觉的对象进行思考的能力就是理解。这两者是同等重要的。没有感性，我们将无法接收任何对象的存在，没有理解我们就无法对任何对象进行思考。没有内容的思想是空虚的，没有概念的直觉则是盲目的。所以，我们有必要使我们的概念感性化，也就是通过直觉把对象加给概念，同样也有必要使我们的直觉智能化，也就是使它们在概念的指导之下。这两股力量的作用是不可相互交换的。理解是无法产生直觉的，而感官也无法进行思维。只有通过这两者的结合我们才能得到知识。但是，这不应导致将两者的贡献进行混淆；而恰恰应该是将它们仔细地加以区别的理由。所以我们应该将关于一般感性的科学，即美学，与关于一般理解的科学，即逻辑，区分开来。

而逻辑又可再被分成两部分来看待，或是一般逻辑，或是对于理解的特殊的运用的逻辑。前者含有思维所必须依循的法则，离开了这些法则人们就无法进行理解，所以这第一种逻辑只负责理解而不管所理解的对象是什么。而对于理解的特殊的运用的逻辑（即第二种逻辑---博主注），包含着对于某种对象进行正确的思维的法则。前者可以被称为元素的逻辑，而后者可被称为这个或那个科学的方法指南。后者在学校里通常被作为科学的预备知识的科目；而实际上，根据人类思维的步骤，这后者所包含的内容是最后才能得到的，是当具体的一个学科基本完善了时候作为最后的修饰而提出的，这是因为人们只有当对一个学科有了相当完整的认识的时候才可能从中总结出一般的法则来。

一般逻辑既可以是纯逻辑也可以是应用逻辑。我们运用前者来从进行理解的经验条件中，也就是从感官的影响中，然后从各种具有偏见的来源，实际上是产生这样或那样的所有的知识的原因中，抽象出想象，记忆律，习惯力，倾向，等等。因为在应用上总是要有具体的环境条件的，所以这种纯逻辑不可能离开了经验而单独作用。所以，纯逻辑必须遵循先验的规则而且是作为理解和推理的准则，在具体应用中不论对象的内容是经验的还是超验的，纯逻辑只针对形式。当一般逻辑被运用于心理学所处理的主观经验条件的时候，它被称为应用逻辑。所以，应用逻辑具有经验的规则，尽管作为一般逻辑的应用逻辑所针对的仍然是对于理解的在忽略了对象的差异的情况下的一般运用。相应地，它既不是理解的一般准则，也不是具体科学的方法指南，而仅仅是一般理解的一种导流剂。

所以我们必须把一般逻辑中负责纯推理纯教义的部分与负责应用（尽管仍是一般的）逻辑区分开来。正确地说，前者是作为表露关于理解所绑定的元素的教义的方法的一种又干又简明的科学。所以逻辑学家们在处理一般逻辑时应记住这样两个原则：

1．作为一般逻辑，它从关于理解的知识的所有内容中以及对象的所有差异中进行抽象，并且只涉及思维的单纯形式。

2.  作为纯逻辑，它与经验毫无关系，而且也不象人们有时假设的那样对心理过程有任何借鉴，因而心理过程对于理解的准则没有任何影响。纯逻辑是一个明示了的教义体，它所含有的一切都是先验的。我所称为应用逻辑的（这与人们通常所赋予这个词汇的含义相反，根据那个含义它应该含有一些由纯逻辑的法则支配的操作）是关于理解的一种表达而且是在具体的理解应用中的法则，也就是说，在人们具有偶然性的既可能帮助也可能妨碍理解的主观条件下的应用理解的法则，而且所有这些法则都是由经验得来的。它负责处理注意力以及注意力的障碍和后果，错误源，怀疑的心态，犹豫，以及信念等。纯逻辑与应用逻辑的关系，就象只含有对于自由意志的一般道德律的纯伦理与关于严格意义上的美德的教义（即在人们或多或少所要受到的情感，倾向，热情的限制的前提之下来考虑关于美德的律的教义）之间的关系。这样的教义永远也不会生产出一个真实的且明示的科学来，因为同应用逻辑一样，它依赖于经验的和心理的规则。

二．超验逻辑

一般逻辑，如我们已经看到的，从所有的知识内容中及所有的知识与对象之间的关系中进行抽象，并且只考虑知识与知识之间的关系的逻辑形式；也就是说，它负责处理思想的一般形式。但是，如同我们从超验的美学所看到的纯直觉和经验直觉的区别，我们也应该在对于对象的纯思想和经验思想之间作一划分。这样做的结果将使我们具有一种不是从所有的知识内容中进行抽象的逻辑。这种异类逻辑，将仅仅含有关于一个对象的纯思维的法则，将排出具有经验内容的知识。它也将负责处理我们了解对象的所依据的模态的源点---只要这个源点不是回归于对象本身。另一方面，一般逻辑与知识的源点无关，而只关心知识的表现形式；只要他们起初是先验的或只是由思想中的经验根据理解所依据的律，一般逻辑就把它们彼此联系起来。所以它只与理解所赋予表现的形式打交道，而不管这些表现从何而来。这里我要做一个标注，希望读者们从现在起就牢记在心。

不是所有的先验的知识都可以被称为超验的，只有那些我们知道某些表现（直觉的或概念的）可以被运用（并知道如何运用）或是纯先验的，我们才能称之为超验的。也就是说，“超验”这个词汇让人想起的是关于知识的先验的可能性的知识，或关于它的先验的运用。对象的空间或先决的几何特征都不是超验的表现；能够被称为超验的是那些不具有经验的源点的表现的知识以及可以与经验的对象有着先验的关系。比如，把空间的概念运用于一般的对象是超验的，但是，如果我们限定在感官所感受得到的对象来谈论空间，那就是经验的了。所以超验与经验之间的这一区别只属于对于知识的判断的范畴，与知识和对象之间的关系无关。所以，可以预见，可以有一些概念虽然与对象是先验的关系，不是纯的或感性的直觉，而只是纯思想---也就是，不具有经验的或美学的源点的概念---我们根据自己的期待构想出了一个关于属于纯理解和推理的知识的科学，在这个科学的范畴里，一切对象都是先验的。这样一个用来确定知识的源点，范围，和客观有效性的科学就叫做超验逻辑。和既与经验也与纯推理知识打交道的一般逻辑不同，超验逻辑只关心与对于对象的先验的理解与推理有关的律。

附：节选的英文原文：

I．LOGIC IN GENERAL

OUR knowledge springs from two fundamental sources of the mind; the first is the capacity of receiving representations (receptivity for impressions), the second is the power of knowing an object through these representations (spontaneity [in the production] of concepts). Through the first an object is given to us, through the second the object is thought in relation to that [given] representation (which is a mere determination of the mind). Intuition and concepts constitute, therefore, the elements of all our knowledge, so that neither concepts without an

intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge. Both may be either pure or

empirical. When they contain sensation (which presupposes the

actual presence of the object), they are empirical. When there is

no mingling of sensation with the representation,they are pure.

Sensation may be entitled the material of sensible knowledge.

Pure intuition, therefore, contains only the form under which

 something is intuited; the pure concept only the form of the

thought of an object in general. Pure intuitions or pure concepts alone are possible a priori, empirical intuitions and empirical concepts only a posteriori.

If thereceptivity of our mind, its power of receiving representations in so far as it is in any wise affected, is to be entitled sensibility, then the mind's power of producing representations from itself, the spontaneity of knowledge, should be called the understanding. Our nature is so constituted that our intuition can never be other than sensible; that is, it contains only the mode in which we are affected by objects. The faculty, on the other hand, which enables us to think the object of sensible intuition is the understanding. To neither of these powers may a preference be given over the other. Without sensibility no object would be given to us, without understanding no object would be thought. Thoughts without content are empty, intuitions without concepts are blind. It is, therefore, just as necessary to make our concepts sensible,

that is, to add the object to them in intuition, as to make our intuitions intelligible, that is, to bring them under concepts. These two powers or capacities cannot exchange their functions. The understanding can intuit nothing, the senses can think nothing. Only through their union can knowledge arise. But that is no reason for confounding the contribution of either with that of the other; rather is it a strong reason for carefully separating and distinguishing

the one from the other. We therefore distinguish the science

of the rules of sensibility in general, that is, aesthetic, from

the science of the rules of the understanding in general, that is, logic.

Logic, again, can be treated in a twofold manner, either as logic of the general or as logic of the special employment of the understanding. The former contains the absolutely necessary rules of thought without which there can be no employment whatsoever of the understanding. It therefore

treats of understanding without any regard to difference in the objects to which the understanding may be directed. The logic of the special employment of the understanding contains the rules of correct thinking as regards a certain kind of objects. The former may be called the logic of elements, the latter the organon of this or that science. The latter is commonly taught in the schools as a propaedeutic to the sciences,though, according to the actual procedure of human reason,it is what is obtained last of all, when the particular science under question has been already brought to such completion that it requires only a few finishing touches to correct and perfect it. For the objects under consideration must already be known fairly completely before it can be possible to prescribe the rules according to which a science of them is to be obtained.

General logic is either pure or applied. In the former we abstract from all empirical conditions under which our understanding is exercised, i.e. from the influence of the senses, the play of imagination, the laws of memory, the force of habit, inclination, etc. , and so from all sources of prejudice, indeed from all causes from which this or that knowledge may arise or seem to arise. For they concern the understanding only in

so far as it is being employed under certain circumstances, and to become acquainted with these circumstances experience is required. Pure general logic has to do, therefore, only with principles a priori, and is a canon of understanding and of reason, but only in respect of what is formal in their employment, be the content what it may, empirical or transcendental. General logic is called applied, when it is directed to the rules of the employment of understanding under the subjective empirical conditions dealt with by psychology. Applied logic has therefore empirical principles, although it is still indeed in so far general that it refers to the employment of the understanding without regard to difference in the objects. Consequently it is neither a canon of the understanding in general nor an organon of special sciences, but merely a cathartic of the common understanding.

In general logic, therefore, that part which is to constitute the pure doctrine of reason must be entirely separated from that which constitutes applied (though always still general) logic. The former alone is, properly speaking, a science, though indeed concise and dry, as the methodical exposition of a doctrine of the elements of the understanding is bound to be. There are therefore two rules which logicians must always bear in mind, in dealing with pure general logic:

1. As general logic, it abstracts from all content of the knowledge of understanding and from all differences in its objects, and deals with nothing but the mere form of thought.

2. As pure logic, it has nothing to do with empirical principles, and does not, as has sometimes been supposed, borrow anything from psychology, which therefore has no influence whatever on the canon of the understanding. Pure logic is a body of demonstrated doctrine, and everything in it must be certain entirely a priori. What I call applied logic (contrary to the usual meaning of this title, according to which it should contain certain exercises for which pure logic gives the rules) is a representation of the understanding and of the rules of its necessary employment in concreto, that is, under the accidental subjective conditions which may hinder or help its application, and which are all given only empirically. It treats of attention, its impediments and consequences, of the source of error, of the state of doubt, hesitation, and conviction, etc. Pure general logic stands to it in the same relation as pure ethics, which contains only the necessary moral laws of a free will in general, stands to the doctrine of the virtues strictly so called – the doctrine which considers these laws under the limitations of the feelings, inclinations, and passions to which men are more or less subject. Such a doctrine can never furnish a

true and demonstrated science, because, like applied logic, it depends on empirical and psychological principles.

II．TRANSCENDENTAL LOGIC

General logic, as we have shown, abstracts from all content of knowledge, that is, from all relation of knowledge to the object, and considers only the logical form in the relation of any knowledge to other knowledge; that is, it treats of the form of thought in general. But since, as the Transcendental Aesthetic has shown, there are pure as well as empirical intuitions, a distinction might likewise be drawn between pure and empirical thought of objects. In that case we should have a logic in which we do not abstract from the entire content of knowledge. This other logic, which should contain solely the rules of the pure thought of an object, would exclude only those modes of knowledge which have empirical content. It would also treat of the origin of the modes in which we know objects, in so far as that origin cannot be attributed to the objects. General logic, on the other hand, has nothing to do with the origin of knowledge, but only considers representations, be they originally a priori in ourselves or only empirically given, according to the laws which the understanding employs when, in thinking, it relates them to one another. It deals therefore only with that form which the understanding is able to impart to the representations, from whatever source they may have arisen. And here I make a remark which the reader must bear well in mind, as it extends its influence over all that follows.

Not every kind of knowledge a priori should be called transcendental, but that only by which we know that -- and how -- certain representations (intuitions or concepts) can be employed or are possible purely a priori. The term 'transcendental', that is to say, signifies such knowledge as concerns the a priori possibility of knowledge, or its a priori employment. Neither space nor any a priori geometrical determination of it is a transcendental representation; what can alone be entitled transcendental is the knowledge that these representations are not of empirical origin, and the possibility that they can yet

relatea priori to objects of experience. The application of space to objects in general would likewise be transcendental, but, if restricted solely to objects of sense, it is empirical. The distinction between the transcendental and the empirical belongs therefore only to the critique of knowledge; it does not concern the relation of that knowledge to its objects. In the expectation, therefore, that there may perhaps be concepts which relate a priori to objects, not as pure or sensible intuitions, but solely as acts of pure thought -- that is, as concepts which are neither of empirical nor of aesthetic origin -- we form for ourselves by anticipation the idea of a science of the knowledge which belongs to pure understanding and reason, whereby we think objects entirely a priori. Such a science, which should determine the origin, the scope, and the objective validity of such knowledge, would have to be calledtranscendental logic, because, unlike general logic, which has to deal with both empirical and pure knowledge of reason, it concerns itself with the laws of understanding and of reason solely in so far as they relate a priori to objects.