According to Mill "Sub duct is a part of any event, as known by previous induction so that some antis accidents have effect and the residency of the event is the effect of the remaining antis accidents. For example - we weight a weight Do. Pay attention to the car and weight. We already know the weight of the car alone. By subtracting the weight of the car from the total weight of the loaded car, we conclude that the difference is the weight of the load. This method is based on Is. On the principle that no one thing can cause a different thing. When we are dealing with a complex phenomenon and we already know the cause of some of them, we conclude that the residual or residual The cause of the phenomenon is to be found among the remaining antis accidents.

The method of residence is a special modification of the method of difference. Because, the principle underlying these two methods is the same, if there are two examples that differ only in the circumstances that exist in one instance and are absent in the other, then the two groups of antic agents alone are different. The reason for other circumstances in which the results of the two groups alone differ. The difference between the two methods is that, in the method of difference, the instance in which the conditions do not arise is supplied by the experiment, while in the residuals of the method, that instance is supplied by deduction from the previous induction.