#system #logic

idea

There are many causes to any consequence. There are two types of causalities.

Necessary causality is the set of causes that had to happen for the consequence to happen.

Sufficient causality is the set of causes that were enough for the consequence to happen.

For example, global warming is a necessary cause for a 500y flood to happen, but also water levels, weather, construction works, etc ; but it is not a sufficient cause. Removing a leaf from a tree is a sufficient cause for the leaf to be detached, but it is not a necessary cause given that all leaves end up on the floor anyway.

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