Symbolically, the method of simultaneous variation can be presented as (with ± represent a displacement): you can consider two similar countries as an example of the method of difference. Country A has a centre-right government, a uniform system and was a former colony. Country B has a centre-right government, a single system, but has never been a colony. The difference between countries is that Country A easily supports anti-colonial initiatives, while country B does not. The difference method would or would not identify the independent variable as the status of each country as a former colony, the dependent variable supporting anticolonial initiatives. This is because the two similar countries have compared, the difference between the two is whether they were previously a colony or not. This then explains the difference with the values of the dependent variables, the former colony supporting decolonization rather than the country without a history of being a colony. This is an example of mills method of simultaneous variation: The evidence seems to show that there is a direct correlation between the degree to which the cause occurred and the degree to which the effect occurred. This is consistent with our usual principle that effects are generally proportional to their causes. This is indeed a sophisticated version of the Common Method, in which we notice not only the occurrence or non-presence of the terms of cause, but also the extent to which each of them took place. Another common diversity of inductive arguments is the finding of a causal link between events.
If we have good reason to believe that the events of a species (causes) are systematically associated with events of another nature (effects), we can change our environment by creating (or preventing) the appearance of certain types of events. This situation is an example of Mills` common method of agreement and difference: the first four students are proof that all those who got sick had eaten coleslaw, and the four matching couples are proof that only those who fell ill had eaten coleslaw. This is a strong combination of the first two methods, as it tends to support our idea that real causes are necessary and that the conditions for their effects are sufficient. Symbolically, the common method of concordance and difference can be presented as: Mills methods are five methods of induction described by the philosopher John Stuart Mill in his book A System of Logic published in 1843. [1] They must shed light on issues of causation. This method is also generally known as the most similar system design in the context of comparative policy. Philosopher John Stuart Mill has developed a series of five methods (or canons) that analyze and interpret our observations in order to draw conclusions about the cause-and-effect relationships they have. Precisely determining the causes and effects is not an easy task.
We can often confuse or misrepreseg the two because we lack sufficient information. Mill`s methods are attempts to isolate a cause from a complex sequence of events. Under the tailings method, if we have a number of factors that are assumed to be the causes of a number of effects, and we have reason to believe that all factors, with the exception of a factor C, are causes of all effects, with the exception of one, we should infer that C is the cause of the residual effect. Even simply referred to as the "common method," this principle represents only the application of methods of concordance and difference.