I have no proof of Natural Rights. What I do have is a combination of innate and environmental responses to the real world that feel the happiness of life’s pleasures whenever I live my life as if these concepts are achievable.
When I attempt to live and strive for the kind of liberty where we treat each other with true equal, individual rights of life, liberty, and the pursuit of happiness, that is when I feel alive and feel like I belong in this world! The Diest, pre-Darwin, Thomas Jefferson certainly embraced these ideas.
Liberty is a relatively new experiment, not much older than Darwin.
I am not saying that we should live as social Darwinists. Quite the opposite. The Chimps are the authoritarians. We are the fifth ape. We need to become fully sentient humans.
If we are not free to choose our own path through life’s maze, then who? If we are not to have liberty now, then when?
Society has a right to justice in the courts, and physical protection from harm of those who would take away your liberty. This includes protection from the outside terrorist criminals, and protection from those on the inside who would rape your daughter, steal your property, or send DEA thugs into your state.
Brute force is something that we can trace back to the modern acceptance of old testament punishments from the Bible. Of course, those are but a continuation of what our early ape ancestors behaved like.
These people, these authoritarians from every frequency of the political spectrum, have had plenty of pre-Constitutional and post-Constitutional attempts to run society. None have given modern concepts of liberty, science, the arts, or literature a fair chance.
Liberty is scientific. It is self-correcting and falsifiable. It is a delicate experiment that the authoritarians need to stop treading on.