Random notes below the fold
Common sense Roman law rooted in natural law which applies to all beings including animals and plant.
Estabilished commonalities, universalities, for all systems of law that might differ substantially but can be best understood by also finding commonalities.
States of mind MATTER — disregarding this is a major failure in modern law.
Pre-existing rights (e.g. to land and water) MATTER — this is ignored by modern law particular eminent domain by the state.
Modern American constitutional law sneers at common law, big mistake.
OPEN ACCESS is heart of common law — this does not ignore need for shared costs (e.g. to build a bridge) but it does limit rights to then block access (e.g. pedestrian and vehicular tolls on every bridge).
Natural law and the ability to know something is wrong rooted in common sense is a strong factor in the importance of jury trials and the right of the jury to overturn the law if it does not apply correctly.
Natural law underlies sustainability. It encourages positive collaboration and discourages negative cohesion. Modernists ignore this distinction.
Contract and tort law ignores natural law, tries to limit rights to those in the written document that is often flawed and incomplete.