The moral hand is a metaphor of five basic ethical principles, one for each finger, summarizing a complete, coherent ethic. (Watch an interview and presentation. For a longer article, see The five fingers of ethics)
–The thumb: rule universalism. You must follow the rules that everyone (who is capable, rational and informed) must follow in all morally similar situations. You may follow only the rules that everyone (who is capable, rational and informed) may follow in all morally similar situations. 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 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 you force a sentient being to do or undergo something that the being does not want in order to reach an end that the sentient being does not share, and 2) if the body of that sentient being is necessary as a means for that end, then you violate the basic right. 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 (animals who need meat in order to survive) 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.