> If we ditched "reasonableness" as a legal concept, even the most basic laws like e.g. the ones about murder would be significantly affected. So what you're proposing is a drastic redesign, and the onus is on you to demonstrate that it is even workable.

Reasonableness is a quick approximation for world view or "the majority values and lived experiences of a specific culture at a specific time and place". For example, dueling is considered murder, but was once considered absolutely reasonable and NOT requesting a duel in some circumstances would be considered a "reasonable" sign of guilt.

Would you convict someone of murder over manslaughter because your gut told you they were guilty? The Southern US has countless cases of innocent black men hanged because they had "reasonableness", but no hard evidence.

Reasonableness is fickle. For example, in self defense cases with video (probably the most important cases concerning reasonableness), the prosecution pushes to review the video frame by frame while the defense pushes to play the video in realtime. Why? because when you see the video in realtime and make snap decisions, the defense seems more reasonable. When you pick it apart frame by frame, you have tons of time to think about all the things you might have done and can convince yourself that maybe lethal defense wasn't needed.

If reasonableness changes so much just by HOW you watch the same video, how can it really be considered reasonable? What is does reasonable actually mean in practice?

It's also worth noting that not all evidence is admitted in trials and the judge has significant ability to shape the outcome of the trial based on what evidence they "reasonably" believe should be included.

> How do you envision the legal system dealing with issues such as intent and negligence without the notion of a "reasonable person"?

I'm not proposing something radically different. I'm proposing we use reasonable doubt instead of reasonable intuition as the primary metric. You can never completely remove reasonableness, but its effect should be mitigated and controlled. If you can't prove something, you shouldn't convict based on the unprovable ideas your world view fabricates that may or may not be accurate.