Consider as an example of the two similar countries difference method. 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. The common method, associated with this weaker hypothesis, requires an equally strong observation: that is, that each of the possible causes, with the exception of A, must be present either in a positive and negative instance, or in a positive and negative instance, and this variant (2.3) always gives the conclusion that A is both necessary and sufficient. So there will not be a method of agreement, a method of difference and a common method, but a number of variations of each. A full survey of all kinds of methods of this type, numbered as follows: A number of 1 to 8 before a decimal comma indicates the mode of adoption. It is therefore assumed that there is a real cause, but that has a very large number of extremely different cases of effect, and only one factor seems to be present in all of them, we can have a real approach to method 8.12.
The various proceedings cover at least a wide range of all possible combinations of potentially relevant factors and their negations. Therefore, it is likely that no condition that is not covered by the formula (A or…) is necessary, and therefore, if there is a necessary and sufficient condition, (A or … ) is so, and therefore A itself is a sufficient condition of the phenomenon. Since the assumptions are still relaxed, the agreement method requires stronger and stronger observations. For example, in 6.12, which is a variant of the positive method with the assumption that the necessary and sufficient condition may be a disjunction of possible causes or negations, the required observation is such a number of positive instances, so that a possible cause, for example. B A, is present in each, but that there is a case for any possible combination of other possible causes and their negations in which this combination exists (i.e., if there are other possible causes, we need 2n different instances). This observation will air condition any district that does not contain A and will show that the necessary and sufficient condition (A or…) is and therefore A itself is a sufficient condition for P in F. A corresponding variant of the negative tuning method (5.14) shows that (A…) is a necessary and sufficient condition, and therefore that A itself is necessary – a strange reversal of the rollers, because in the simplest variants, the method of positive tuning was used to recognize a necessary condition and the negative condition a sufficient condition.