There are two broad ways of approach to scientific knowledge. One, known as empiricism, is the approach that emphasises experience and the facts that result from observation and experimentation. The other, known as rationalism, stresses reason and the theories that result from logical inference.

The empiricist collects facts; the rationalist co-ordinates and arranges them. Theories and facts are required in the construction of knowledge. In sociological inquiry both are significant. A theory unsubstantiated by hard, solid facts are nothing more than an opinion. Facts, by themselves, in their isolated character, are meaningless and useless. As Immanuel Kant said, "theories without facts are empty and facts without theories are blind". All modern sciences, therefore, avail themselves of both empirical and rational resources. Sociology is not an exception.