Although Mills` methods are an important part of the serious study of natural phenomena, they have significant constraints. These methods can only be applied with care if all relevant pre-gonal circumstances are taken into account, which cannot be guaranteed in advance. « Method of agreement. » Merriam-Webster.com Dictionary, Merriam-Webster, www.merriam-webster.com/dictionary/method%20%20Consecite. Access 30 Nov 2020. 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. What prompted you to look for the method of agreement? Please tell us where you read or heard it (including the quote, if possible). This reasoning illustrates Mill`s method of residues: many elements of a complex effect are demonstrated by reliable causal beliefs from several elements of a complex cause; All that remains of the effect must have been produced by the remnants of the cause. Note that if we accept the truth of all the relationships of cause, this method becomes an application of the deductive argument. Symbolically, the common method of adequacy and difference can be represented as: thus, we could see, on the same example, that you felt a little sick after eating an oyster, while your sister was rather comfortable eating a few, and your father became seriously ill after eating ten in a row. Since the variation in the number of oysters corresponds to a variation in the severity of the disease, it would be reasonable to infer that the diseases were caused by oysters. John Stuart Mill (1806-1873) was an English philosopher who wrote on a wide range of subjects ranging from language and science to political philosophy.
The so-called « mill » methods are five rules for the search for the causes he has proposed. It has been assumed that some of these rules were in fact discussed by the famous Islamic scientist and philosopher Avicenna (980-1037).