Neither. Proximate cause is the concept that describes the relationship between an error or omission and the damages alleged. The ability to foresee the consequences is an aspect of the alleged negligence of the defendant.
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The way I learned negligence in torts is this: the elements required to prove negligence are duty (standard of care), breach of that duty, causation and damages. Causation has 2 subparts: the factual cause and the legal cause. Proximate cause is the legal cause, which basically refers to the relationship between the law to the facts. It is a tricky concept that is confusing for most law students. The last part of negligence is damages.
Negligence requires duty, breach of duty, legal causation (also known as proximate cause) and damages.
Not all causation is proximate causation. It must be reasonably foreseeable to the defendant.
Do an internet search on Palsgraf v. Long Island Rail Road. That is the leading case establishing the principle of proximate cause.
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