Scientific methods are broadly of two kinds, one technical method and the other logical methods.
Technical methods, which are also called the technological methods, are used for the measurements or manipulations of phenomena under the observation. Sciences like physics and chemistry are mostly dependent on the use of such technical methods in the form of special apparatus or laboratory equipment for the measurement and recording various phenomena like electricity, temperature, volume, weight, pressure; and since various sciences differ in their subject matter and scope, accordingly the technical methods used by them are also different.
Logical methods, on the other hand, are the methods of reasoning according to the nature if data is collected or observations are made by the scientist. Drawings of inference from the given observation involve the process of reasoning in a logical order. Logical methods are common to all the sciences, whether they are natural sciences or social sciences. In other words, every scientist, whether working on physics, chemistry, economics or mathematics, must have a proper understanding of the logical methods in order to rationally reason out various inferences and arrive at the valid conclusions from his investigation.
There are two types of logical methods: one is the inductive method and the other is the deductive method. Inductive logic is a method of reasoning whereby we go from less general to more general propositions. On the basis of a few observations and facts we arrive at a general law. To take an example, if we know that persons X, Y and Z are mortal, we may generalize that all human beings are mortal. This means that the facts about mortality of X, Y and Z have led us to conclude that all human beings are mortal.
In deductive logic we have some law and theories before us on the basis of which we make deductions and test those deductions with the help of facts. Here we proceed with certain facts or principles which are already known to us and then deduce some results out of them. For example, X is a man. From this the conclusion logically follows that X is mortal. In this method, we have drawn a conclusion from a generalization to explain a particular situation. Both, inductive and deductive methods, though mutually inverse processes, are used extensively in scientific analysis. Induction gives rise to the hypothesis which is verified with the help of deduction. In other words, induction gives theories and laws, and deduction verifies the truth of those generalizations by applying them to fresh particular cases.
