Proximate vs. Ultimate Causes02 Jun 2018
Simple definition from Wikipedia:
A proximate cause is an event which is closest to, or immediately responsible for causing, some observed result. This exists in contrast to a higher-level ultimate cause (or distal cause) which is usually thought of as the “real” reason something occurred. In most situations, an ultimate cause may itself be a proximate cause for a further ultimate cause.
Example from Guns, Germs, and Steel:
Yet another type of explanation lists the immediate factors that enabled Europeans to kill or conquer other peoples—especially European guns, infectious diseases, steel tools, and manufactured products. Such an explanation is on the right track, as those factors demonstrably were directly responsible for European conquests. However, this hypothesis is incomplete, because it still offers only a proximate (first-stage) explanation identifying immediate causes. It invites a search for ultimate causes: why were Europeans, rather than Africans or Native Americans, the ones to end up with guns, the nastiest germs, and steel?
Farnam Street goes into further detail by describing techniques for establishing and mapping ultimate causes.