Right, and "root cause" only has meaning in the context of some goal being achieved. If you're a detective investigating the scene of the accident to determine culpability, your goal is very different than if you're a civil engineer investigating the accident for ways to improve traffic management. It'd be really strange for either of them to conclude their report with a recommendation to increase World Health Organization's budget for alcohol abuse treatment.

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Therefore, Your Honor, my client is innocent. Why has this tragic accident occurred? I shall tell you to look no further than the root cause...

The Big Bang.