The next step in procedure of induction is formation of a hypothesis. A hypothesis is a provisional supposition to explain a phenomenon whose explanation is not known.
In the process of observation after eliminating the changing circumstances the common factor present in all the instances is considered seriously to be the cause. Since, nature is very complex it requires great insight to imagine what might be the cause of a phenomenon.
To find out the real explanation of a phenomenon, we consider some possible situation. That is on the basis of our observation we fix upon one condition to a possible explanation of the phenomenon.
That is considered as a hypothesis. To explain an event what seems to be the most probable explanation in the context is provisionally admitted. This provisional supposition’s put to test under varying circumstances in a regulated way.
In the process of test either the hypothesis is accepted or rejected on the basis of its agreement or disagreement with the fact respectively.
That is if further observation confirms the hypothesis by supportive .evidence then the hypothesis is corroborated. If it does not corroborate the facts, then the hypothesis is rejected and a fresh one may be thought of. The process goes on till a satisfactory explanation of the event or events is found out.
Whewell attaches great emphasis on framing of a legitimate hypothesis. According to him framing of a hypothesis is the most important step in the procedure of induction.