Critique On The Premise Of Formal Logic

The original requirement for a thinking expression is that it accords with logical law. Logical law here means formal logic. In this sense, formal logic is the judge that can adjudicate whether a proposition is true or not. However, can the basic law of formal logic be a rational rule to make judgment? In other words, is it itself an objective standard? What we need to think about is whether there is some self-evident premise in formal logic, and whether such premise is reliable. In this thesis, my aim is to reflect on formal logic and to quest on the logic of necessity in our mind.According to the analysis of formal logic, we know that in essence formal logic is a kind of extensional logic, which is to deduce according to the necessary relation of extensions. In formal logic, there are two elements in a concept, its intension and its extension. With the help of formal logic, we neglect the concrete content of thinking and only regard its general form. Hence, the necessity of form can not get from the intension of a concept but of its extension. That is why I call formal logic an extensional logic. Actually, such extensional logic embodies both in propositional logic and in lexical logic.In fact, the extension of a concept is determined by its intension. But formal logic is a kind of logic which makes deduction according to the relation of extensions, it does not care for the concrete intension of the concept. Therefore, in formal logic, nor is there concrete intention and extension, neither relation of the extensions of some concept. We can only get the aforementioned content from the existed knowledge system and take them as fixed and true things in formal logic. Just in this sense, science and common sense become the premises of formal logic. We take the existed knowledge or scientific knowledge as the premises of formal logic, means that we believe science is the most correct way that man understands the world. The scientific way is to understand the world by constructing thinking on the world. But the rational premise of such a way is our thinking and being obey the same law. That is to say, the law of thinking motion should be the law of being.However, how can we believe that our thinking and being obey the same law? Philosophers began to think about the problem that how can objective understanding be possible since Descartes. Such epistemological change actually concerns about the basis of identity between thinking and being. In order to answer the question that how can objective understanding be possible, philosophers are divided into two groups: the empiricists and the rationalists. The former try to unite thinking and being with being, while the latter with thinking. All of them hope to figure out identity of thinking and being. However, since both the two groups of philosophers put thinking and being in opposite positions, they can not argue identity of thinking and being in a reasonable way. And of course, they can not demonstrate the practical necessity of objective knowledge.In Germany, it is Kant who begins a new way of exploring objective knowledge. He gives us a perfect generalization on contribution and limitation of traditional formal logic. He also proposes that we should build up an intensional logic which can insure the unity of formal necessity and necessity of content. Essentially, in the extensional logic, we take the necessary process that objective knowledge comes into being as research object. Hence, in Kantian philosophy, the intensional logic and epistemology become one thing. Kant calls such intensional logic apriori logic, a logic which is about the knowledge formation of phenomena with the basis of the transcendental understanding of reason. In Kant's apriori logic, the unity of thinking content and its form is achieved with the unity of intuitionistic phenomena formed by transcendental perceptual intuition and the transcendental conception of understanding. The key point in such unity is the necessity in the transition from intuition to thinking and transition from sensibility to understanding, while the transition happens with the basis of the dialectic motion of transcendental imagination. On the one hand, imagination owns the function of sensible intuition, on the other hand, it can achieve the synthetic motion of understanding. Because of this, imagination becomes the bridge between sensibility and understanding. Such theory on the dialectic character of imagination is the dialectics of imagination hiding in Kant's apriori logic, which forms the core of knowledge necessity on phenomena. Nevertheless, Kant himself does not realize the key effect of imagination dialectic in his apriori logic. He even denies the dialectic of rational inference, and calls it illusory logic. In Kant's idea, the reason causing such antinomy is that reason hopes to know about the thing-in-itself which is hiding out behind phenomena, but what we can get with sensible intuition is only phenomena. This is Kant's negative dialectic.Fichte goes on Kant's way and insists his rule of self. Fichte takes off the supposition of thing-in-itself which in Kantian philosophy is the origin of knowledge. Instead, he believes self is both the origin of understanding form and that of understanding content. What Fichte builds up is a kind of dialectic on the original motion of rational self. He tries to deduce all of the concepts and to construct the mansion of all knowledge by the dialectic motion of self. However, Fichte's self logic is not an objective logic on the formation and development of understanding but a kind of subjective logic, because he still takes self as limitation of self and the motion of self in Fichte's idea still needs an external stimuli by its contradictory. Schelling is the first one who goes beyond Kant and Fichte in philosophical principle. He holds that knowledge is the unity of subjection and objection, and the unity of thinking and being. In Schelling's idea, the logic on development of understanding is something starting from thinking and reaching objection at last. Such a process is the object of transcendental philosophy. As a result, Schelling regards intuition as the main function of philosophy. In transcendental philosophy, Shcelling explores the development of necessity in understanding by explaining the dialectic development of intuition. That is what Shcelling calls the developmental logic of objective understanding. But since Shelling takes intuition as the highest thing, he does not build up an intensional logic system by means of development of concepts.The intensional logic of rationalism is achieved by Hegel in his conceptual dialectic at last. In Hegel's opinion, reason is not only a substance, but a subject. Due to this, a substance must achieve its self-understanding by ceaseless endeavor. Such self-understanding is necessary to show with the help of the motion of human thinking, that is, the logic of being is necessary to show by the logic of the motion of human thinking. Since Hegel's intensional logic is a kind of logic on the intensional development of idea which is embodied by the intensional development of human thinking, conceptual dialectic is just intensional logic. In conceptual logic, subject and object, thinking form and thinking content reach their unity. In this sense, reason as the substance that unite subject and object also permits the existence of object understanding. Hegel's intensional logic is based on its presupposition of ontology. With such a method, Hegel changes the motion of human thinking into self motion of absolute idea, and also he changes things in reality into logical concepts in the process of idea's development. This is what Marx criticizes reason without body. By criticizing Hegel's mysticism on his conceptual dialectic, Marx understands the development of understanding according to the real development of the history of human society. With such a critique, Marx achieves the intensional logic of praxism. In Marx's intensional logic, praxis is priori to conception. In Marx's method, the unity of history and logic is based on the real history.In my idea, the significance of Marx's intensional logic on praxism can be concluded into three aspects. Firstly, it denies the validity of all methods that try to build up some metaphysical truth. It is because Marx explores understanding by understanding human history, the real human life is emancipated from the horror of truth. Secondly, it regards the real human praxis as the real basis of understanding's development. From this point, it is necessary to research the role that language plays in human praxis. This is the consensus between Marx's philosolophy and the linguistic change achieved by contemporary philosophers. Thirdly, it still resorts to theoretic universality though it cares much on experiential research. In this sense, Marx's theory becomes a universal theory in current time, and also becomes the world view that can guides human praxis.