Induction and Deduction

A pair of interconnected basic methods in human thinking. Induction is the method of thinking that rises from the individual to the general, and includes complete induction and incomplete induction. Deduction is a method that moves from general principles to individual conclusions, i.e., the method of reasoning that infers the attributes, relations that individual things have in a certain class of things according to the general attributes, relations of things in a certain class of things, it usually consists of three parts: premises, rules of logic and conclusions. Induction is the motion from the individual to the particular, and deduction is the motion from the general to the particular. Induction and deduction are two methods in the process of knowledge that are both opposed to and connected with each other, the two presuppose and supplement each other. On the one hand, induction is the basis of knowledge, but induction cannot be separated from deduction. Without deduction, there is no induction. Induction begins with the collection of empirical materials or facts, whether it is the collection of empirical materials or the arrangement of empirical materials, they should be guided by certain theoretical principles. Here is where deduction comes into play, which determines the end and direction of inductive activity. Moreover, mere induction cannot distinguish the essential and non-essential attributes of things. The induction that a property is common to a certain class of things does not conclusively prove that it is the essential property of such things, nor does it account for the relation between the commonality of one class of things and the commonality of another class of things in an evolutionary process. This must be supplemented and corrected by deduction. On the other hand, deduction cannot exclude induction, without induction, there would be no deduction either. Induction is the basis of deduction, and as the starting point of deduction, axioms, laws and assumptions are derived from non-deductive methods including induction. Deduction from the commonality to the individuality cannot reveal the diverse and colorful attributes of individual things, and the conclusions of deductive reasoning must be verified and enriched by induction. If the newly discovered individual facts do not conform to the general conclusion drawn by deduction, the conclusions drawn by deduction must be re-examined and corrected. The history of development of science fully proves the dialectical relation between induction and deduction. Any major scientific discovery must use induction and deduction at the same time. Many important laws of nature were first revealed by induction, then proved by deduction, and finally became scientific laws only through the test of practice. Generally speaking, induction has a very important role in the study of empirical material, but when science enters theoretical thinking, deduction plays an increasingly important role, especially in the establishment of a theoretical system and in the search for the internal logical structure of a theoretical system, deduction has become the main method of thinking.