The moral hand, a complete and coherent ethical theory

The moral hand is a metaphor of five basic ethical principles, one for each finger, summarizing a complete, coherent ethic.

-The thumb: the principle of universalism. You must (may) follow the rule that everyone who is capable must (may) follow in all morally similar situations towards all morally equal individuals. Prejudicial discrimination is immoral. We should give the good example, even if others don’t. Just like we have to place the thumb against the other fingers in order to grasp an object, we have to apply the principle of universalism to the other four basic principles.

-The forefinger: justice and the value of lifetime well-being. Increase the well-being (over a complete life) of all sentient beings alive in the present and the future, whereby improvements of the worst-off positions (the worst sufferers, the beings who have the worst lives) have a strong priority. Lifetime well-being is the value you would ascribe when you would live the complete life of a sentient being, and is a function of all positive (and negative) feelings that are the result of (dis)satisfaction of preferences: of of everything (not) wanted by the being.

-The middle finger: the mere means principle and the basic right to bodily autonomy. Never use the body of a sentient being as merely a means to someone else’s ends, because that violates the right to bodily autonomy. The two words “mere means” refer to two conditions, respectively: 1) if in order to reach an end (e.g. saving someone) you force a sentient being to do or undergo something that the being does not want, and 2) if the body of that sentient being is necessary as a means for that end, then you are not allowed to treat that being in that way. A sentient being is a being who has developed the capacity to want something by having positive and negative feelings, and who has not yet permanently lost this capacity. The middle finger is a bit longer than the forefinger, and so the basic right is a bit stronger than the lifetime well-being (e.g. the right to live). The basic right can only be violated when the forefinger principle of well-being is seriously threatened.

-The ring finger: naturalness and the value of biodiversity. If a behavior violates the forefinger or middle finger principles, the behavior is still allowed (but not obligatory) only if that behavior is both natural (a direct consequence of spontaneous evolution), normal (frequent) and necessary (important for the survival of sentient beings). As a consequence predators are allowed to hunt. Just as lifetime well-being is the value of a sentient being, biodiversity is the value of an ecosystem and is a function of the variation of life forms and processes that are a direct consequence of natural evolution. The valuable biodiversity would drastically decrease if a behavior that is natural, normal and necessary would be universally prohibited (universally, because you have to put the thumb against the ring finger).

-The little finger: tolerated partiality and the value of personal relationships. Just as the little finger can deviate a little bit from the other fingers, a small level of partiality is allowed. When helping others, you are allowed to be a bit partial in favor of your loved ones, as long as you are prepared to tolerate similar levels of partiality of everyone else (everyone, because you have to put the thumb against the little finger).

-The palm: universal love and solidarity. Do not hate or despise anyone. Love all living beings with respect and compassion. The palm holds the moral fingers together.

The forefinger, middle finger, ring finger and little finger correspond with resp. a welfare ethic, a rights ethic, an environmental ethic and an ethic of care.

These five fingers produce five principles of equality.

-The thumb: the formal principle of impartiality and antidiscrimination. We should treat all equals equally in all equal situations. We should not look at arbitrary characteristics linked to individuals. This is a formal principle, because it does not say how we should treat someone. The other four principles are material principles of equality. They have specific content and are generated when the thumb is applied to the four fingers.

-The forefinger: prioritarian equality of lifetime well-being (the principle of priority for the worst-off). As a result of this priority, we have an egalitarian principle: if total lifetime well-being is constant between different situations, then the situation which has the most equal distribution of well-being is the best.

-The middle finger: basic right equality. All sentient beings (with equal levels of morally relevant mental capacities) get an equal claim to the basic right not to be used as merely a means to someone else’s ends.

-The ring finger: naturalistic behavioral fairness. All natural beings (who contribute equally to biodiversity) have an equal right to a behavior that is both natural, normal and necessary (i.e. a behavior that contributes to biodiversity). Natural beings are beings evolved by evolution. E.g. if a prey is allowed to eat in order to survive, a predator is allowed to do so as well (even if it means eating the prey).

-The little finger: tolerated choice equality. Everyone is allowed to be partial to an equal degree that we can tolerate. If you choose to help individual X instead of individual Y, and if you tolerate that someone else would choose to help Y instead of X, then X and Y have a tolerated choice equality (even if X is emotionally more important for you than Y).

The five moral fingers can be applied to the production and consumption of animal products (meat, fish, eggs, dairy, leather, fur,…):

-The forefinger: compared to humans, livestock animals are in the worst-off position due to suffering and early death. The loss of lifetime well-being of the livestock animals is worse than the loss of well-being that humans would experience when they are no longer allowed to consume animal products. Livestock and fisheries violate the forefinger principle of well-being.

-The middle finger: the consumption of animal products almost always involves the use of animals as merely means, hence violating the mere means principle of the middle finger.

-The ring finger: animal products are not necessary for humans, because well-planned vegan diets are not unhealthy (according to the Academy of Nutrition & Dietetics). Biodiversity will not decrease when we would stop consuming animal products (on the contrary, according to UN FAO the livestock sector is likely the most important cause of biodiversity loss). Hence, the value of biodiversity cannot be invoked to justify the consumption of animal products.

-The little finger: we would never tolerate the degree of partiality that is required to justify livestock farming and fishing. Hence, tolerated partiality cannot be invoked to justify the consumption of animal products.

It follows that veganism is ethically consistent, and the production and consumption of animal products are ethically inconsistent.

-The thumb: give the good example, even when other people continue consuming animal products. From this principle, it follows that veganism is a moral duty.

That is a very good and logical argument but I doubt it would make anybody vegan because a human urge to eat lamb chops usually trumps a non-existent human urge to be logical and moral. As usual with dealing with human beings, you can be right but very few people care. Sorry. I am still going to eat hot dogs for lunch today.

I guess the best that can be done is improve the treatment of livestock to bring the ethical inconsistency down to a tolerable rate. Hunting may have been justifiable in the past because of the ring finger principle but due to overpopulation that is no longer the case. However it is still unfortunately the case that our brains tell us that bacon tastes good, so you are looking at more of a biology problem here, not an ethical one.

Then again, farming plants is also pretty harmful when it is done unethically (which it very frequently is) and reduces biodiversity damages ecosystems etc. Although you do not have the sentient-being argument in that case.

But I am less worried about whether I am killing sentient beings and more about whether I am reducing the biodiversity so I would like a little help from science here in making better varieties of plants that will take up less space and provide more nutrition. I'm not talking about mass-producing gmo's like the giant companies currently do, I am talking about actually putting some scientists in charge of this and not releasing products that haven't even been tested properly. Then maybe we could have foods with so much nutritional value and such little space that a store could have all the food for a town grown in a greenhouse on its roof, which would mean near-zero environmental impact.
Also some work is being done on creating meat artificially so there will be no mistreating-sentient-beings problem.

I prefer consistency, because that is the only way to avoid arbitrary, opportunistic behavior. If you are allowed to be inconsistent and let your taste preferences dominate, than so am I and everyone else. You cannot want that if you are rational. I'm sorry, I want to listen to your rational self, not your greedy self.
Human hunting today is no longer justigiable, because it is not necessary for humans.
Finally: a vegan diet is better for the environment (for biodiversity) than current consumption and production of livestock products in most countries. Livestock farming is likely the biggest threat to biodiversity (says FAO)

You are an exception in this category, and what is irrational here is that you expect that everyone can be rational too. That is not so; if it were, the world would not have so many problems. I am not saying your argument is wrong, on the contrary, it is right in every way, but you are one of the few people who are logical enough to follow it. The rest of the world is made of Homo Sapiens.

And I, like almost everyone else on the planet, do not have a rational self, and believe a variety of inconsistent things. I might be exceptional in this category that I actually admit this.