In philosophy a proximate cause is an event which is closest, 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.
- Example: Why did the ship sink?
- Proximate cause: Because it was holed beneath the waterline, water entered the hull and the ship became heavier than the water which supported it, so it couldn't stay afloat.
- Ultimate cause: Because the ship hit a rock which tore open the hole in the ship's hull.
In most situations, an ultimate cause may itself be a proximate cause for a further ultimate cause. Hence we can continue the above example as follows:
- Example: Why did the ship hit the rock?
- Proximate cause: Because the ship failed to change course to avoid it.
- Ultimate cause: Because the ship was under autopilot and the autopilot received bad data from the GPS.
Separating proximate from ultimate causations frequently leads to better understandings of the events and systems concerned.
In ethology
In ethology, the study of animal behavior, causation can be considered in terms of these two mechanisms.
- Proximate causation: Explanation of an animal's behavior based on trigger stimuli and internal mechanisms.
- Ultimate causation: Explanation of an animal's behavior based on evolution. Requires that behavioral traits, like physical ones, are genetically heritable, and then explains behavior using an explanation of why this specific behavioral trait was favored by natural selection.
These can be further divided, for example proximate causes may be given in terms of local muscle movements or in terms of developmental biology (see Tinbergen's four questions).
