Causation

Legal cases and accident investigations usually deal with a particular event and ask what caused it. For example, when in February 2003 the space shuttle Columbia burned up during reentry, investigators looked for the cause of the disaster. In the end, they concluded that a chunk of foam insulation that had broken off and hit the wing during launch was the cause of a rupture in the insulating tiles, which was the cause of the shuttle's demise during reentry. Philosophers call this event causation, or actual causation, or token-causation.

Policy makers, statisticians, and social scientists usually deal with kinds of events, like graduating from college, or becoming a smoker, or playing lots of violent video games. For example, epidemiologists in the 1950s and 1960s looked for the kind of event that was causing a large number of people to get lung cancer, and they identified smoking as a primary cause. Philosophers call this type-causation, or causal generalization, or causation among variables.

The properties of causal relationships are different for actual causation and for causal generalizations. Actual causation is typically considered transitive, antisymmetrical, and irreflexive. If we are willing to say that one event A, say the Titanic hitting an iceberg on 12 April 1912, caused another event B, its hull ripping open below the water line and taking on water moments later, which in turn caused a third event C, its sinking a few hours later, then surely we should be willing to say that event A (hitting the iceberg) caused event C (sinking). So actual causation is transitive. (Plenty of philosophers disagree, for example, see the work of Christopher Hitchcock.) It is antisymmetrical because of how we view time. If a particular event A caused a later event B, then B did not cause A. Finally, single events do not cause themselves, so causation between particular events is irreflexive.

Causal generalizations, however, are usually but not always transitive, definitely not antisymmetrical, and definitely not irreflexive. In some cases causal generalizations are symmetrical, for example, confidence causes success, and success causes confidence, but in others they are not, for example, warm weather causes people to wear less clothing, but wearing less clothing does not cause the weather to warm. So causal generalizations are asymmetrical, not antisymmetrical, like actual causation. When they are symmetrical, causal generalizations are reflexive. Success breeds more success and so forth.