A problem with saying rights should be THE foundation of any good ethical system is that you have no basis for determing which things are rights, and which or not, and which rights have greater priority.  You can either then arbitrarily just pick them, or declare as Locke had they are given by God and inalienable.  And this inalienable is a stronger position than just picking them, or saying they are alienable because that means they can be traded in a market and exchanged for something else.  At that point, you come up with a relativist market that is close to Utilitarianism, and reduces ethical decisions to financial calculations, which undermines a strength of rights-based systems, that means the rights are fairly clear and non-negotiable.

Now, saying that an ethical-based system is based around, and operates on the basis of upholding rights doesn't mean that a person making ethcal decisions needs to be only informed by a rights-based ethical system to make ethical decisions.  One can end up know the weaknesses of rights-based ethical systems, and while favoring it, lean on other system of ethics to make decisions.  Of course, the risks in doing this is to end up not making sound ethical decisions, but ones based on personal preferences.

The way I see it, a heirarchy of rights should follow something similar to Maslow's Heirarchy of Needs:



So, naturally, one's right to live is a greater right than someone else's right to body or health, for instance, and definitely higher than someone's right to self-esteem (thus, abortion, even in cases of rape or incest, would be wrong).

However, this also places gay rights (as far as marriage goes) and religious rights on the same level ("right to the lack of prejudice" vs "right to morality"). So coming up with a solution to those issues would still be a dilemma.

But all systems of ethics ultimately boil down to personal preference anyway. The established schools of thought were created by philosophers in their own images, and people basically just pick and choose what ethics that they personally find to be the most appealing.

Still, it's really not as hard as you're making it out to decide how rights should be prioritized. If liberty and self-ownership are the most fundamental rights,  everything else flows from that. Therefore human interaction should be voluntary and free of violence and coercion, and anything that requires the initiation of coercion - such as that needed to enforce the claims that you have a right to things provided by others or that you have the right not to hear disagreeable opinions - is wrong.

There is a catalog on rights, as with a rules based system you have a catalog of rules. The human-rights-charta is such a catalog. You haven't shown, that the human rights have conflicts, that aren't resolvable with priorities usually applied to them. You only could make up other rights that no one ever had in a rights-catalog to show that it doesn't work.

I show you, that no rules-based-system can work, the way you apply your argument:

The rule "Don't follow any rule!" is a valid rule. As this contradicts a rule-based ethical system a rules-based ethical system cannot work.

The argument you cannot determine which things are rights can be pointed at every other foundation of society. You have no system to declare which rules are good rules for instance.

Naturally you pick some (and Lockes position of rigts given by god is nothing else as that he has picked some). And that's not that hard. Most of the world has agreed on human rights for more than 50 years now.

And if you think that is a weakness of rights, tell me which base of ethics isn't done by picking some things over overs? You always bring up Utilarism. But it is hard to determine the value of things. Usually it is picked. Along the lines of: a human life ios worth more than a bread.

That's sorta what i've been thinking this whole time.

It's like saying "A vegetarian who eats all fruits can't work because it can be argued Chicken is a fruit!"

I mean... you can argue that... but there isn't any real basis or truth behind it.

Personal preferences in this context means that a person rigs the ethical decision-making so that it comes out to benefit the person doing this all the time.  A good system of ethics will causes everyone to yield from time to time, and restrain them as needed.  It will also cause them to act with better character.

I would go with what Hayek wrote on the subject of tradition and morals developed in a society.  He argued such evolved over time, reaching conclusions individuals alone couldn't reach by pure intellect.  These arose as a bunch of proven rules of thumb, and actually likely not a system at all. Values and temperments in society also arose this way. 

I would say here that, in this, in a fully functioning society, the idea of rights came much later, starting with the likes of Locke.

Still in the domain of the individual. The state still needs people to execute good works, even if the government is ultimately footing the bill, see: Peace Corps, Americorps.

A person with an ethical system that involves a sense of duty, and not just "things are fine if I leave everyone alone" are more likely to end up doing things like volunteering.