Broadly speaking, natural sciences are sciences of nature, and social sciences are sciences of Man or human society. They deal with two different kinds of phenomena. They are different in their nature, behaviour and qualities. Phenomena of Nature can be observed and experimented upon with scientific objectivity, which gives us uniform and universally valid and ascertainable laws and results. On die basis of these exact laws, it is possible to predict and control these events and phenomena.
Hence Natural Sciences are also called exact sciences. They are, for example, the sciences of Physics, Chemistry, etc. The laws of Physics remain true and valid whether they are studied and applied in Pakistan or France. The laws of chemical processes remain die same whether they are taking place in Africa or Europe. Nay, they remain the same whether they occur on earth or on the moon and stars.
For instance, two atoms of hydrogen when combined with one atom of oxygen will produce water, whether this combination takes place in Pakistan or in Peru, on Earth or on Mars. It means that the laws of Physics, and Chemistry, are fixed, certain, uniform, universally true or valid and predictable. But the same cannot be asserted about the laws, principles and theories of the social sciences, which deal with human life and society.
The difference between the two, however, is not of kind but of degree. Natural sciences are exact sciences, while social sciences are less so. With the advance in human knowledge, social sciences are also becoming more and more exact, precise and predictable.