The domain of moral philosophy has always interested me like no other, because of its immediate influence on lifestyle and everyday choices. Do you keep a promise, even if it's inconvenient? Do you give money to beggars or tell them to earn it themselves? If you could help someone by breaking the law, would you do it? The answers to these questions depend heavily on what you deem to be right and wrong, on the rights and obligations you believe people ought to have. Here I will describe a moral theory stated in terms of a conservation law.
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Before jumping in, one important remark. I believe that philosophy is the formalization of intuition, just like physics is the formalization of reality. As such, philosophy is intrinsically subjective, since intuitions (although generally uniform) may vary from person to person in important ways. This already imparts a degree of moral relativism. I fully embrace it, but deem it to be counterproductive, just like solipsism in epistemology: if we don't know anything, then we can just go home, there's nothing to talk about. Similarly, if everyone is free to define their own moral laws which are all equally valid, there is no morality to talk about. A set of moral beliefs doesn't just get to be "valid", it must earn the right to be respected. I will try to show that the conservation of rights framework does earn that right.
The balance between rights and obligations has probably been understood from time immemorial. The leader of a primal tribe has the right to the best food and women, but is obligated to keep the tribe safe and manage it successfully. If he fails to fulfill his obligations, he is stripped of his rights. The principle is similar for monarchs and subjects, for governments and citizens, for buyers and sellers, for parents and children. "The more you have rights, the more obligations you take on" is a golden rule or morality, just like "Treat others in the way you want them to treat you". Let's introduce some concrete definitions:
Right --- an agreement within the society that a person may perform a certain action, now or in the future, without judgement or opposition;
Obligation --- an agreement within the society that a person must perform a certain action, now or in the future, lest they may be judged and punished.
The definitions are kind of similar, and in fact dual: an obligation to to X is precisely the lack of right not to do X. The right to do Y is precisely the lack of obligation not to do Y. We may therefore abandon the notion of obligations altogether, and formulate everything in terms of rights. Our golden rule then becomes: "If you gain a right, you must give away another right in return". Everything has a price. In fact, we can see any intuitively "fair" or "lawful" human interaction as an exchange of rights:
When you buy a pound of meat at the marketplace, the butcher surrenders the right to the meat, and you surrender the right to the money it costs;
When two businesses sign a contract, they both impose obligations on each other, which is equivalent to exchanging rights;
The employer receives the right to use some of the employee's time and knowledge, while the employee receives the right to claim some of the employer's revenue.
There are also "unfair", "dishonest" interactions, where the balance is not respected:
A thief robbing your apartment acts immorally, since they strip you of the right to hold and use your belongings, and in return, only undertake the risk of being caught. If they are caught and put under obligation to pay you the price of stolen items, the balance is preserved, and morality is restored.
A murderer acts immorally by stripping a person of their right to live; If the murderer is caught, a death sentence will set the record straight (given that you actually catch the right person, of course, which is why death sentences are still not a great idea in reality).
Lying is immoral if the liar gets away with it: they gave you false information, gaining the right to inform part of your decision-making, and you receive no rights in return. The balance becomes preserved if either 1) the false information takes no part in your decision-making, or 2) the liar is held accountable to his claims, e.g. you receive the right to tax them should their information be wrong.
These intuitions lead us to formally define morality.
A set of human actions is considered moral (or fair, or just) if it conserves the amount of rights that all people have. It is considered immoral otherwise.
I have to note here that the above definition is overly restrictive. It implies, for example, that if I hold the door for a lady exiting the building after me, the act is immoral unless she finds a way to "pay me back". Similarly, if a group of people goes to a restaurant and one of them covers the bill, this incurs a "debt" on the rest. It makes all daily interactions transactional, removes kindness and goodwill. The way to mitigate this is to relax the definition of moral by only requiring that the balance of rights be preserved in the long term, allowing short-term fluctuations. If you pay for your partner's food on a date, you're not acting immorally, since they will likely do the same on the next date. If, however, you continue to pay for all consecutive dates, that leads to an imbalance in rights. In our daily lives, we do each other small favors all the time, likely without keeping track; this is fine as long as the long-term balance of favors is preserved.
Another critical remark is that this morality definition is symmetric in the sense that your action is immoral regardless of whether you take extra rights or give them. This is the somewhat controversial part. Stealing is immoral, but so is charity. If this seems counterintuitive, think about it this way: if someone gives you a large amount of money for free, explicitly not requiring that you return it in any way, this is equivalent to them saying "you have absolutely nothing to give me in return, but you can have my money anyway", a statement which I find condescending and patronizing. One can say that charity establishes a difference in status between the donor and the receiver, strips the receiver of their human dignity.
Of course, most people don't care about their dignity more than they care about, say, having food. Proclaiming the immorality of charity is easy when you don't need charity yourself. But to me, that implies not that charity is good (although the ones in need of it certainly wouldn't complain), but that the situation which makes charity necessary is inherently immoral: it drives people so far into despair as to forsake their own dignity. If I ever find myself in need of financial assistance, I would more gladly take out a loan than accept a donation. The former allows me to remain a fully functional and dignified member of society who can be held accountable for his actions.
First of all, both rights and obligations are defined in as "social agreements", meaning that without a society, they become meaningless. A single person on a deserted island is not bounded by any moral law. What is slightly more interesting, however, is that two people on an island are also completely unconstrained. This is because even if person X claims that, for example, person Y owes him 1 apple, person Y may simply deny it, and then it's word against word with no objective truth, since we cannot define "owing" as anything but a social construct. Even if in the past, in exchange for some service, person Y promised to give person X an apple, he may now claim to have lied, and that he doesn't see anything wrong with lying to get what he wants. This may be a bad survival strategy for someone left on an island with only one other person, but it's not immoral. The balance of rights is preserved, since neither of the two people has any rights to begin with. Morality appears when a third person joins the two people on the island. Then, we can speak of rights and obligations imposed on one person by the remaining two.
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The core principles of libertarianism can be derived as a consequence of the conservation of rights. Indeed, if a person acts in a way that does not affect other people, then he neither gains nor loses rights, only exercises them. Similarly, other people neither gain nor lose rights, and the balance is preserved. In other words, exercising one's freedom in a way that respects the freedoms of others is a moral act. As a consequence, under the conservation of rights, abortion is moral until the fetus is intellectually mature enough to be reasonably given rights. I will not argue when this age of maturity should be. Suicide is also a moral prerogative of any person who does not owe outstanding debt, in which case suicide would violate their obligations.
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There are some implications on the relationship between parents and children. Since the parent takes on the obligation to raise and provide for the child, in order to make their relationship moral, the child must take on an obligation as well, usually by surrendering their right to free movement, the right to choose their place of education, etc. However, despite the apparent morality of the situation, we must remember that the child does not ask to be born, and so this exchange of rights is analogous to a butcher forcefully giving you a pound of meat and then forcefully taking its cost out of your wallet. Since you did not agree to this exchange beforehand, shoving the meat in your face does not grant the butcher the right to withdraw its cost from you. That piece of meat becomes nothing but charity, which we have seen to be immoral. Therefore, childbirth can only be moral if the parent then proceeds to leave the child to their own devices, neither giving, nor requiring anything of them. But that would be needlessly cruel and pointless, as a child has no means to survive out in the world alone. In other words, the conservation of rights implies anti-natalism, the belief that children shouldn't ought to be born.
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Romantic relationships may be viewed under the conservation of rights framework. Since they are typically long-term endeavors, both parties in the relationship must be on equal footing in order for the long-term balance of rights to be respected. In other words, asymmetric relationships (in the extreme case -- abusive) are immoral, and as to my limited knowledge, they don't fare well from the psychological standpoint as well. The view of a relationship as a "contract", an exchange of rights, may seem to remove its critical components of emotional attachment and romantic flair, but one does not in fact contradict the other. Relationships are contracts, where both parties agree to support each other and share their experience in life. The awareness of this unwritten agreement need not hamper the feeling of love -- on the contrary, knowing that your presence is beneficial to your partner and theirs is to you, can ever strengthen the emotional bond, which in turn will reinforce the contract. But I digress.
Philosophical concepts like "pleasure", "suffering", "right", and "wrong" are very hard to quantify, but some sort of measurement is still necessary to decide whether an exchange of rights preserves the balance or not. This means that our exchange evaluation machine will have to run on v i b e s. Typically, we may say that a sequence of actions (i.e. transactions in rights) leaves the balance preserved if every person involved in any of these actions neither owes, nor is being owed to, by both their honest opinion and the opinions of others. If you were given a right, you must give a right away (perhaps to a different person), such that the chain of rights loops back to the one who gave away the initial right. And the value of the right you received should be no less and no more than the value of the right you gave away. And other people who observe these transactions should also deem these values to be roughly equal. That's about as precise of a measurement as I can produce.
As explained before, the philosophy of the conservation of rights is based on the ancient idea of fair exchange. Hence this is hardly anything novel, and knowledgeable people can kindly point me to the literature where these views are already expressed. Still, what I always liked about philosophy is that anyone can do it -- all it takes is a curious mind and an ability to ask and answer questions.
The theory I outlined above may seem harsh and cynical, mechanical, lacking of a sort of kindness and empathy to be expected from the definition of "good". Not to mention that some of the implications are deeply controversial and still heatedly discussed. I, however, do not think that emotion has no place in serious philosophical discourse, where we care about the truth more than anything else, to the extent that "truth" can have a meaning. And indeed, I think that the definition of morality given above is true, in the sense that it aligns with my own intuitions.