February 8, 2019
Recall some of Weber's insights:
In other terms:
Usually to explain something specific that has happened/we observe (the effect). This is about attributing a cause for some observed outcome/"explaining" the outcome.
We want to know what happens if we do some action or some action (the cause) happens. (Could be a specific action or not) This is about the contribution of some cause to an effect.
"\(X\) is the cause of \(Y\) if and only if \(X\) is necessary or sufficient for \(Y\)": cause \(X\) must always and invariably lead to the effect \(Y\)
\(X\) is a cause of \(Y\) for a specific case if the both of the following are true:
Manipulation focus on individual cases.
\(X\) is a cause of \(Y\) if and only if a mechanism connects \(X\) to \(Y\).
"A man takes a trek across a desert. His enemy puts a hole in his water can. Another enemy, not knowing the action of the first, puts poison in his water. The man dies on the trip. The enemy who punctured the water can thinks that she caused the man to die, and the enemy who added the poison thinks that he caused the man to die. In fact, the water dripping out of the can means the poisoner is wrong."
Three ideas of causality are philosophically different, but…
If we say that \(X\) is a cause of \(Y\) for a particular case, whether it is necessary/sufficient, or \(X\) is manipulated by us, or \(X\) is the start of a chain of mechanisms leading to \(Y\), then the following statements must be true:
All causal claims we make, can be restated in terms of a counterfactual statement:
or
Counterfactual approach to causality says that:
\(X\) is a cause of \(Y\) for some specific case(s), if when \(X\) changes and everything is the same except \(X\), \(Y\) changes.
Causal Claim: Donald Trump's election victory caused an increase in hate crimes.
counterfactual claim: If Donald Trump had not won the election, there would be fewer hate crimes.
Causal Claim: Restricting gun ownership does not reduce gun violence
counterfactual claim: If there were more restrictions on gun ownership (in a country), the amount of gun violence would be the same (or more).
"Donald Trump's election victory caused an increase in hate crimes in 2017."
\[\underbrace{If \ \ Trump \ \ had \ \ not \ \ won \ \ the \ \ 2016 \ \ election}_{\text{If-clause in Subjunctive Mood}}, \\ \underbrace{there \ \ would \ \ have \ \ been \ \ fewer \ \ hate \ \ crimes \ \ in \ \ 2017.}_{\text{Then-clause in Conditional Mood}}\]
"The presence of fraternities on campus cause more sexual assault."
\[\underbrace{If \ \ there \ \ were \ \ no \ \ fraternities \ \ on \ \ campus}_{\text{If-clause in Subjunctive Mood}}, \\ \underbrace{there \ \ would \ \ be \ \ fewer \ \ sexual \ \ assaults.}_{\text{Then-clause in Conditional Mood}}\]
"Building a wall between the US and Mexico will reduce illegal immigration to the United States."
\[\underbrace{If \ \ Trump \ \ built \ \ a \ \ border \ \ wall}_{\text{If-clause in Subjunctive Mood}}, \\ \underbrace{there \ \ would \ \ be \ \ fewer \ \ illegal \ \ immigrants}_{\text{Then-clause in Conditional Mood}}\]
In our present/past tense examples, the counterfactual claim is about what would have happened if something else had happened (instead of what did happen). These "alternate universes" did not take occur, they are not "factual", but "counterfactual".
In our future-tense example: Trump will either build or not build a border wall. Only one possibility will become "fact" and happen, the other will not happen and be "counterfactual".
One way to understand link between counterfactuals and causality is potential outcomes:
potential outcomes are what the same case would do under different possible "worlds" where they are exposed to the supposed cause \(X\) or not.
\(Immigration_{\ Wall}\) is the number of illegal immigrants that would come to the US if Trump built a wall.
\(Immigration_{\ No \ Wall}\) is the number of illegal immigrants that would come to the US if Trump did not build a wall.
The causal effect of the wall on immigration would be:
\[Immigration_{\ Wall} - Immigration_{\ No \ Wall}\]