In our discussion of happiness, we have not covered two important issues:

  1. 1.

    On human happiness, we have not discussed the number of (human) individuals enjoying happiness or suffering negative happiness.

  2. 2.

    We also have not discussed happiness beyond humanity, particularly the issues of animal welfare/suffering.

The first problem is discussed in Appendix E. Here, we consider the second problem.

When we lived in Hong Kong over 1997, we shopped in the Shatin and Taipu wet markets often. We saw fish sellers cutting their life eels alive in halves, letting them wriggling in pain. I guess this is partly to attract attention and partly to show that their fish are very fresh. I argued with them, saying that the eels would be very painful. No one challenge me on this. But one seller replied, ‘If I cannot sell my fish, I will also be painful.’ It may be true that if only one seller cannot use this method while others could, he may sell less fish. However, if this cruel practice is prohibited by law, all fish sellers will still be able to sell their fish. Thus, such practices that inflict huge suffering on animals with no or negligible benefits to humans, should definitely be prohibited with strong sanctions against violators. I wrote on this and also emailed several relevant government offices in Hong Kong. Thus, I was happy to learn that the Hong Kong authority recently issued guidelines for the humane killing of fish for discussion. I hope that some good guidelines will soon be put into practice.

Though there is no such terrible cutting of life eels in halves in the West that I know of, the practice of wiping horses in racing is also something that should be banned. If all riders cannot wipe their horses, fair competition can still be carried on.

Why should we be concerned with animal welfare? As happiness is of intrinsic value and the rational ultimate objective (Chap. 5), the increase in our morality is ultimately reflected in our concern with the happiness of others. The degree of our morality is mainly measured by how much we are willing to sacrifice our own happiness to increase the happiness of others. The extent or scope of our morality is mainly defined by the set of these ‘others’ whom we are concerned with.

In ancient times, apart from oneself and family members, most people perhaps were mainly concerned with the bosses and the king/queen. After such movements like the glorious revolution in 1688, democracy gradually replaced imperial authority; the scope of moral concern increased to all nationals, and then to all human beings. This should increase further to all those with affective sentient feelings. This is likely to be a subset of all animal species. Ignoring the possible existence of gods, ghosts, and the like, there is no need to expand beyond this set, as plants and viruses are likely not affective sentients. Some biologists extend the concern to all living things inclusive of plants. This is excessive as life itself does not have intrinsic value. Thus, plants have only instrumental values by contributing to the happiness of animals with affective feelings.

Obviously, a Chinese individual will think that the morality of an English person who is only concerned with all individuals in England is lower than that of an English person who is not only concerned with all individuals in England, but also all individuals in the world, including the Chinese. Similarly, the morality of a person who is only concerned with all human individuals is lower than that of a person who is concerned not only with all human individuals, but also all animals with affective feelings. For an individual English/Chinese person, he may think that, with the same time and/or costs, it is more important to help one’s country folks than foreigners. However, if we could help many persons in other countries with little costs, we should not preclude this option. Similarly, some persons may think that it is more important to be concerned with human welfare. However, if we could reduce animal suffering a lot at little costs on humans, we should also not preclude this option. Thus, we should not only be concerned with the welfare of other fellow human beings, but also with animal welfare.

Using the highest standard of morality, it may be argued that, all affective sentients, human or animal, should be equal; one welfare unit of any affective sentient, in itself (not ruling out the appropriate consideration of indirect effects on others and in the future) should have the same weight. While moral-philosophically valid, this highest level of morality is difficult to achieve in practice. However, we should at least have some degree of concern for animal welfare, avoiding unnecessarily inflicting suffering on animals at the very least.

Personally, I was very concerned with animal welfare long time ago. In 1995, I published a paper in an A* journal called Biology and Philosophy, proposing a field of study called ‘welfare biology’. Two decades later, a scholar interested in animal welfare, Max Carpendale, interviewed me on the motivation and background of writing that paper. After seeing the interview on Carpendale’s website, the editor of an academic journal, Relations: Beyond Anthrocentrism, published the interview in a 2015 issue of the journal (Carpendale 2015). In 2018, 80,000 hours also interviewed me on this and other issues. This paper on welfare biology seems to have attracted more attention than most of my papers in economics.

There are three basic questions in economics: What (to produce)? How? For whom? In my 1995 paper, I also raised three basic questions for welfare biology: Which (species are capable of welfare)? Whether (their welfare is positive or negative)? How (to increase their welfare)? Next, I used Darwinian theory of evolution and some basic economizing principle to help answer these basic questions, reaching some conclusions (but far from complete).

First, it may be argued that species without flexibility in their behavior have no affective feelings and hence are not capable of welfare or suffering. The generation of affective feelings requires energy costs. Thus, these feelings must contribute to the survival and reproduction fitness of the individual to avoid elimination from natural selection. However, the feelings of pleasure and pain themselves do not contribute to fitness. For example, when you see a tiger and feel terrified, this feeling alone does not help you to survive. This feeling must affect your activities, like running away or hide somewhere, to increase your chance for survival. Similarly, you feel nice seeing a beautiful lady; this nice feeling itself does not increase your fitness. It has to prompt you to mate with the lady to pass on your genes. If feelings of pleasure and pain do not increase your fitness but are costly, they will be selected against and hence cannot survive. They must affect your choices. For example, when seeing an animal, whether you should catch and eat it, or run away to prevent being eaten by it: the so-called ‘fight or flight’ decision is an important choice. The ability to make such flexible choices depending on the conditions of the situation (like the size of the animal, whether you have some weapon, etc.) which you may size up and decide on the spot, is important for your survival.

Some behavioral patterns of animals are completely fixed by genetic programs in advance. For example, a frog is born with the ability to jump around, swallowing small flying objects, as this help it to eat many insects and helps it to survive. However, if you put a frog in a confinement with many insects that do not fly, the frog will not be able to eat them and will starve to death. For another example, when we touch some very hot thing, our arm will withdraw itself to avoid being burnt. This reaction is automatic without thinking and is controlled by our spinal cord. If all the activities of a species consist only of such pre-programmed fixed patterns, it does not need to make flexible choices and hence it does not need affective feelings. Hence, natural selection will ensure that species not capable of any flexible choice will also not be capable of suffering and welfare. This helps us to answer the first basic question in welfare biology: Which species are capable of welfare? Only flexible species are. If we can establish that certain species completely lack flexibility, we may rule them out and not be concerned with causing any suffering on them. Though flexibility or not is still not easy to establish, the existence of affective feelings is even more subjective and difficult to establish. Hence, this first proposition in welfare biology is helpful.

Only flexible species are capable of welfare; however, this does not necessarily mean that we may rule out many species. The recently developed affective neuroscience shows that all mammals, and likely most if not all vertebrates, have affective feelings. In fact, ‘hedonic brain mechanisms are largely shared between humans and other mammals’ (Berridge and Kringelbach 2011, Abstract). Moreover, a paper in Science (Fossat et al. 2014) shows that even crayfish, which is not a vertebrate, has worries. When confined to a space with no escape, a crayfish secretes a chemical in its brain, a chemical we know that we will secrete in our brain only when we are worried. This strongly suggests, if not proves, that even crayfish is capable of worries. Also, arguably, worry is a higher form of unhappiness than just bodily pain. Thus, many species are capable of enjoyment and suffering.

The second basic question in welfare biology is: Whether the (net) welfare of animals are positive or negative? While not conclusive, my 1995 paper suggests that the answer is likely to be negative. This is based on the following two points. The first is based on the fact that, in most species, the number of offspring a mature female typically has over the lifespan is in hundreds, thousands, or more. In equilibrium and on average, only two of these many individual members will survive to adulthood and have successfully pass on their own offspring. The overwhelming majority of the others have a life of running away from predators in fear and finally got eaten or starve to death. Some of them may manage to survive until adulthood and be able to compete to mate. However, apart from the two lucky ones, the majority again fail to mate. It is difficult to imagine that a life like this will have more pleasures than pains. As there are many more unsuccessful than successful (in eventual mating and passing on the genes) individuals, overall negative welfare is likely. The second ground for this negative welfare conclusion is based on some economic-evolutionary theorizing. While my original 1995 paper suggests likely negative welfare from this ground, the issue is still being debated (Groff and Ng 2019).

According to happiness surveys, people in most countries are on average happy. We are also an animal species; how come our welfare is not negative? Happiness surveys are recent. If surveys were taken when we were still struggling on the life-and-death line, with most children starving to death or eaten by animals, our welfare would also likely be negative.

The third basic question in welfare biology is: How to increase animal welfare? Answers to this question could be very wide-ranging. However, to focus on some easy measures without too high costs, apart from banning pointless infliction of suffering on animals like the cutting of life eels in halves as mentioned above, an obvious area springing to mind is reducing suffering of animals we farm for food. We farm chicken, ducks, pigs, lambs, cows, etc. and eat their meat. If they suffer negative welfare in such a life, we are committing a double crime: make them suffer and then kill them for food.Footnote 1 On the other hand, if we could improve the living conditions of our farmed animals such as to increase their net welfare from negative to be positive, eating farmed animals is not morally bad. If we do not eat them, they would not have a chance of living at all. Then, there is no reason to be a vegetarian on moral grounds. The health ground for being a vegetarian or even a vegan is of dubious validity, as in our long history of evolution, we ate animals. The case for reducetarian (reducing instead of stopping eating animal products) is more supportable; see https://www.reducetarian.org/.

A simple way to reduce the suffering of our farmed animals is to increase their cage sizes, especially for the factory farming of chicken. The objection to this by producers that it would increase their costs and reduce their profits is based on incorrect economics. Chicken farming is largely under condition of free competition. Thus, in the long run, producers only earn normal profits. The institution of a drastic increase in cage sizes may lead initially to substantial increases in costs. However, in the long run, the increases in costs will be reflected in higher prices of chicken meat and eggs. The producers will still be earning normal profits. However, consumers will have to pay higher prices. Many of them would be glad to pay higher prices if the suffering of animals could be reduced substantially. For the majority of consumers who tend to over-consume meat, it is likely that higher prices will make them better off, just like a tax on cigarettes makes smokers better off (Gruber & Mullainathan 2005). For others, they still should pay higher prices, just like polluters should pay for the harm of pollution. (For animal suffering reduction, see also Ng 2016, 2019b.)

It may be thought that while the rich could pay for the higher prices easily, the poor will be harmed significantly. The issue of rich-poor or inequality is important but should be addressed separately. A person is rich or poor depending on her total purchasing power, not on the amount of chicken she consumes. Thus, we should pursue equality at the general equality policy focusing on total purchasing power. On specific measures including animal welfare or factory farming, we should follow the principle of efficiency supremacy. In this way, we can achieve the highest degree of equality at the same efficiency costs (Ng 2019a, Chap. 5).

For wild animals, we know even less. If my answer to the second basic question is correct, their net welfare is negative. However, it is more difficult to reduce their suffering (than that of our farmed animals). Some animal welfarists believe that we should at least not encroach upon their territories, reducing their living space. However, if their net welfare is negative, then while the contraction if their territories may involve transitory increases in suffering, in the long run, with lower number of individuals, their total suffering will also decrease. This is not clearly worse. In any case, I believe that, in the very long run, we have a duty to help increase the net welfare of even wild animals, hopefully to a positive level at least. Though not immediately feasible, we should try at least after significant advances economically, scientifically, technologically, and morally. Before this is feasible, we should try to prohibit pointless cruelty and reduce at least the suffering of our farmed animals as suggested above. Also, while we may have reasonable guidelines in experiments involving animals, we should not be too strict on this, as this would slow down scientific and technological advances upon which the salvation of animals will ultimately rely on.