1. Philosophical Question of the Day! Let’s suppose that you and your family members (Mom, Dad, and Sister) went to eat a buffet dinner at the Golden Corral down the street. Now all four of you are sick to your stomach! How can you determine what caused the illness?? Come up with a way to figure this out…

2. MILL’S METHODS Of Logic

3. Example: Suppose you drew up a table of the food taken by each family member. Let’s look at ways we can discover the cause of the illness. OysterBeefSaladNoodlesSick?? MomYes DadYesNo Yes SisterYes No Yes YouYesNoYesNoYes

4. Method of Agreement The method of agreement helps show that a certain factor (or factors) is necessary for bringing about a certain effect One can use the method of agreement to undermine a causal link between an effect and some purported cause by showing that sometimes the effect occurs without the factor The method of agreement says that if all cases where an effect occurs, there is a single factor that is common in all of those cases. So with this method, what is the cause of the illness? OysterBeefSaladNoodlesSick?? MomYes DadYesNo Yes SisterYes No Yes YouYesNoYesNoYes

5. Method of Difference The method of difference helps establish that a certain factor is sufficient for bringing about a certain effect One can use the method of difference to undermine a causal connection by showing that the presence or absence of the factor makes no difference to the observed effect Suppose the table is now different. In this case, you are the only one who did not get sick. The only difference between you and the others is the cause. What is the cause?? OysterBeefSaladNoodlesSick?? MomYes DadYes SisterYes YouYes NoYesNo

6. Joint Method of Agreement and Difference A combination of the methods of agreement and difference Compare a variety of situations in which a certain factor is present to similar situations in which that factor is absent. Then show that a certain effect is observed in all and only those instances in which that factor is present In the example, the join method is a matter of applying both the methods of agreement and difference. So in this case, what is the cause? OysterBeefSaladNoodlesSick?? MomYes DadYes NoYes SisterYes NoYes YouYesNo YesNo

7. Method of Concomitant Variance Demonstrate that quantitative variations in an effect are systematically related to quantitative variations in a particular factor In the same example, we might find that you felt a little sick having eaten one oyster, whereas your sister felt really sick after eating a few, and your father was critically ill after eating 10 in a row. Since the variation in the number of oysters corresponds to variation in the severity of the illness, is it rational to infer that the illnesses were caused by the oysters? OysterBeefSaladNoodlesSick?? MomYes DadYes NoYes SisterYes NoYes YouYesNo YesNo

8. Method of Residues Show that all of the factors known to have some influence upon a certain effect cannot explain the observed level of the effect. Then attribute the residual influence to an unexamined one The method of residues is most effective in cases where one cannot directly measure the level of influence a factor has over some effect In this new example, what is the cause of the illness? OysterBeefSaladNoodlesSick?? MomYes DadNo Yes SisterYesNo Yes YouNo Yes