The Psychological Origins of the Doctrine of Double Effect

The doctrine of double effect (DDE) is a moral principle that distinguishes between harm we cause as a means to an end and harm that we cause as a side-effect. As a purely descriptive matter, the DDE is well established that it describes a consistent feature of human moral judgment. There are, however, several rival theories of its psychological cause. I review these theories and consider their advantages and disadvantages. Critically, most extant psychological theories of the DDE regard it as an accidental byproduct of cognitive architecture. This may provide philosophers with some reason to question its normative significance.