Research On Hempel's Theory Of Scientific Explanation

Science not only describes natural phenomena, but also discovers natural laws and natural phenomena. So scientific explanation is an important aim of science, and it is a key problem of the study of philosophy of science. Now this problem still is under drastic discussion in the domain of western philosophy of science. There is a crucial philosophical transition between the beginning and the end of the twentieth century. At the beginning of the century, the dominant view was that science is in capable of furnishing explanation; at the end, explanation is widely viewed as an important goal of science. Hempel is a scientific philosopher, and his study on scientific explanation plays a key role in promoting this transition. Hempel's covering laws method dominates philosophy of science from the fifties to the sixties of the twentieth century. It has profound influence. We can say that Hempel's theory of scientific explanation is one of the greatest philosophical achievements of the twentieth century and that it has very important theoretic significance and practical significance for modern philosophy of science. If we want to lucubrate Hempel's scientific explanation, we must know the philosophical foundation of his scientific explanation. This essay firstly analyzes the epistemological foundation and the methodological foundation of Hempel's scientific explanation. Concretely speaking, the epistemological foundation of Hempel's theory of scientific explanation mainly consists of three aspects, that is, logical empiricism theory source, logical empiricism philosophical aim and the change of empiricist criteria of cognitive significance. As an important representative of logical empiricism, Hempel commits himself to revise logical empiricism and make an outstanding contribution for the stability and spread of logical empiricism school. He is an acute critic in logical empiricism and an influential philosopher in the twentieth century, such that his scientific explanation theory is to achieve logical empiricism basic creed as an aim. It comes to light that the philosophical thought of logical empiricism has two main sources: one comes from the empirical tradition of Hume, Comte and Mach and so on; the other comes from logical atomism and modern logic of Frege, Russell and Wittgenstein and so on. Logical empiricism combines the method of modern logic with traditional empiricism and developes the method of logical analysis which is originated by Frege and developed by Russell and Wittgenstein. The main aim of logical empiricism is to put forward a clear and precise empiricism theory on our cognition of world. Anti-metaphysics and unity of science are the main philosophical aim, basic creed and kernel notion of logical empiricism. Logical empiricists view science as rational enterprise and try to make philosophy scientific. If they want to provide definitely reliable basis for knowledge, they must eliminate metaphysics. For this enterprise, logical empiricists view scientific knowledge as linguistic system and logically analyze scientific knowledge to find the characteristic of scientific knowledge. That is to find the criteria of cognitive significance and eliminate metaphysics from philosophy. Of course, Hempel constantly makes great effort for this aim,and he systematically analyzes and criticizes original logical empiricist criteria of cognitive significance. He revised it on the basis of affirming that the general intent of the empiricist criterion of meaning was basically sound. Hempel thought cognitive significance as a characteristic of interpreted systems. Because only the whole theory system had the cognitive significance, and cognitive significance in a system was a matter of degree. We can't dichotomize it into significant and non-significant. The methodological foundation of Hempel's theory of scientific explanation mainly consists of two aspects, that is, the development of logic from Frege and Hempel's confirmation theory. Modern logic provides a kind of systematic scientific method for philosophy which can analyze language and be called logical analysis method. This method is the basic method of logical empiricism which applies logic to philosophy, language and science and makes them logical. Hempel is influenced by his teacher Hans Reichenbach and commits himself to apply modern logic to scientific theory. His scientific explanation adequately presents his thought. His scientific explanation has the characteristic of logicism which determined by the development of logic and science. In other words, the development of logic from Frege provides methodological foundation for it. Confirmation and scientific explanation are two aspects of scientific methodology. Confirmation is the foundation of scientific explanation, and confirmation has affinity with scientific explanation. If we want to explain given phenomena scientifically, we must firstly put forward several different hypotheses and test them with experience which relate to confirmation. And as start of scientific explanation, theories or hypotheses ordinarily require to be confirmed to the extent. Hempel's theory of scientific explanation is on the basis of this kind ofepistemology and methodology. Raising the model of scientific explanation is the basic approach of realizing the unity of science for logical empiricism. Scientific explanation is logical, formalization and anti-metaphysics, which is a realization of logical empiricist philosophical creed. We can say that Hempel makes the notion of unity of science precise. Secondly, Hempel's theory of scientific explanation is the logical reconstruction of scientific explanation. In the essay, "Studies in the Logic of Explanation"(1948), Hempel and Oppenheim studied the problem of scientific explanation and raised the model of deductive-nomological (D-N) explanation. Subsequently in the book, "Aspects of Scientific Explanation"(1965), Hempel lucubrated the model of inductive-statistical (I-S) explanation. D-N explanation and I-S explanation are called standard explanation model in the domain of philosophy of science. Furthermore, Hempel also reviewed the problem of pragmatic aspects of explanation. It is the kernel of Hempel's theory of scientific explanation that scientific explanation is viewed as logical argument by general laws. Hempel followed the basic creed of logical empiricism and tried to found his scientific explanation theory from the logical syntax analysis point of view. He used absolutely formalized language and extended to semantic aspect on this basis. He also constructed absolutely formalized scientific explanation model, whose essential aim was to answer "why-question". Firstly, Hempel founded a predicative logic model language L, which consisted syntax and semantic aspects. After that Hempel reviewed the structure of key conception of lawlike sentences, theory and explanation, and defined their truth from the semantic point of view. Hempel presented conditions of adequacy of proposed explanation, that is, logical conditions and empirical condition. Logical conditions of adequacy consist three items: thefirst is that the explanandum must be a logical consequence of the explanans; the second is that the explanans must contain general laws; the third is that the explanans must have empirical content, i.e., it must be capable, at least in principle, of test by experiment or observation. Empirical condition adequacy consists one item, that is, the sentences constituting the explanans must be true. Afterward, Hempel predigests above conditions of adequacy of scientific explanation and raises two basic requirements, that is, explanatory relevance requirement and testability requirement of scientific explanation. Hempel makes off three kinds of scientific explanation model, that is, D-N model, D-S model and I-S model. D-N model means that the laws in explanans are universal and the relation between explanans and explanandum is deductive in ideal scientific explanation; D-S model involves the deduction of a statement in the form of a statistical law from an explanans that contains indispensably at least one law or theoretical principle of statistical form; I-S model means that explanation of particular facts or events by means of statistic-probabilistic laws thus present themselves as arguments that are inductive or probabilistic in the sense that the explanans confers upon the explanandum a more or less high degree of inductive support or of logical(inductive) probability; they will therefore be called inductive-statistical explanations, or I-S explanations. Besides, Hempel emphasized the role of laws in scientific explanation. He thought laws were the middle process which contacted special circumstance condition with some kind of occurrence of given things, and special circumstance condition could be used to explain the occurrence of given things. Hempel also applies the logical reconstruction creed of logical empiricism to the domain of humanities and social science which consists of three aspects: the first is the function of general laws in history; the second is on the problemof human action explanation; the third is on the problem of function explanation in anthropology and sociology. This essay summarizes three characteristics of Hempel's theory of scientific explanation by expounding contents of Hempel's scientific explanation: the first is that scientific explanation viewed as argument is the footstone of Hempel's scientific explanation; the second is that Hempel's theory of scientific explanation is absolutely formalized logical reconstruction for scientific explanation; the third is that laws is very important in scientific explanation. Thirdly, even though Hempel's theory of scientific explanation makes the problem of scientific explanation be the main aim of science and realizes the essential change of scientific explanation notion in science, it also faces many challenges which consist of four aspects: the first is the problem of self-explanation of E; the second is the puzzle of explanatory relevance, that is, the problem of irrelevant factor participating in explanation; the third is the symmetry thesis, that is, the problem of whether explanation is symmetry with prediction; the fourth is the problem of ambiguity of statistical explanation and the high probability requirement. Of course, Hempel actively revises his scientific explanation when he faces many criticisms of philosophers so as to accord with the practice of science, such as the study of self-explanation of E, the amendment of the requirement of maximal specificity, etc. In allusion to these problems, philosophers try to solve these problems from three routes in principle: the first is epistemological route whose main representative character consists of Van Fraassen, Philip Kitcher, etc. Van Fraassen raised pragmatics model of scientific explanation and emphasized the role of context in scientific explanation. He indicated that explanation was tripartite relation about theory, fact and context. Philip Kitcher raised a uniform model ofscientific explanation and used the conception of unification to relate explanation with understanding. He viewed ideal explanation as an argument. The second is model route which thinks that scientific explanation doesn't essentially deduct phenomena by laws, but constructs a model and uses metaphor or analogy to understand and explain world. The main representatives of this idea are Mary Hesse and Nancy Cartwright. The third is ontological route which thinks that scientific explanation isn't argument, but opens out the causality and mechanism of the occurrence of phenomena and clarifies its status in the whole natural picture and hiberarchy. The main representatives of this idea are Wesley C. Salmon, James H. Fetzer, etc. Wesley C. Salmon raised statistical relevance model, and James H. Fetzer raised causality relevance model. Above three routes on scientific explanation have common aspect, that is, they all think that explanans related with explanandum in science. Their difference is that they use different theory start to expound the conception of explanatory relevance from different point of view. They all have traits and different puzzle of theory. This essay thinks that we can't absolutely negate covering laws model, because it has problem. In fact, covering laws principle plays very important role in scientific explanation. Our understanding of world is promoted by subsuming kinds of phenomena under the general laws. The study on scientific explanation should be from the combination of syntax, semantic and pragmatic point of view, and three aspects must be together. The syntax and semantic point of view means to logically analyze scientific explanation. The pragmatic point of view means to consider different knowledge situation and the factor of context. Finally, this essay properly and objectively appraises the philosophical significance and methodological value of Hempel's theory of scientific...