Introduction: Altruism and Evolution. The question “Does Altruism Exist?” might seem like a silly topic for a book but the claim that it does not exist has a long history in philosophical, political, economic, and biological thought. Add to this that the word “altruism” did not exist until coined by the humanist philosopher Auguste Comte in 1851 and we have a question that takes into deep intellectual waters. In this book I use evolutionary theory as a navigational guide. The question of whether altruistic traits (defined in terms of action) can evolve has been controversial among evolutionary theorists in the past but has been largely resolved. This book offers a “post-resolution” account.

Chapter 1: Groups that Work. Two meanings of altruism need to be distinguished, which refer to: 1) how people act and; 2) the thoughts and feelings that cause people to act. These two meanings exist in a one-to-many relationship; any given action can be motivated by more than one set of thoughts and feelings and our preference for one set over another is based primarily on the actions that they produce. Altruism defined in terms of action is closely related to group-level functional organization, which requires members of groups to perform services for each other. We can therefore begin with the question “Do functionally organized groups exist?”, which is simpler to answer than “Does altruism exist?”. The answer is “yes” for both human and nonhuman species. At least some of the time, social groups are so functionally organized that they invite comparison to single organisms.

Chapter 2: How Altruism Evolves. The following premises are so basic that they are unlikely to be wrong: 1) Natural selection is based on relative fitness; 2) Traits that are “for the good of the group” seldom maximize relative fitness within groups; 3) A process of between-group selection is therefore required to explain the evolution of functionally organized groups. As E.O. Wilson and I put it in a 2009 article, Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary. In a multi-tier hierarchy of units (Multilevel Selection Theory), the general rule is adaptation at any given level requires a process of selection at that level and tends to be undermined by selection at lower levels. These statements are true not only for the highly self-sacrificial traits typically associated with altruism, but also for most of the coordination mechanisms required for groups to function as adaptive units. The balance between levels of selection is not static but can itself evolve. A major evolutionary transition—from groups of organisms to groups as organisms—takes place when mechanisms evolve that suppress disruptive forms of selection within groups, causing between-group selection to become the primary evolutionary force.

Chapter 3: Equivalence. The controversy over group selection was resolved, not because one side “won” but because all theories of social evolution (e.g., MLS theory, Inclusive Fitness Theory, Evolutionary Game Theory, and Selfish Gene Theory) were shown to rely upon the same three premises listed in Chapter 2. They offer different perspectives on the same causal processes, rather than invoking different causal processes. Arguing one against the others is like someone who knows only one language arguing that other languages are wrong. The concept of Equivalence—theoretical frameworks that deserve to coexist by virtue of offering different perspectives—should be part of the basic training of scientists, along with the concept of paradigms that replace each other and the process of hypothesis formation and testing that takes place within each paradigm and equivalent framework. The amount of time and effort saved avoiding pointless controversy would be colossal.

Chapter 4: From Nonhumans to Humans. Answering the question “Does Altruism Exist?” requires a consideration of humans per se in addition to the evolutionary forces that apply to all species. Our starting point is the concept of major evolutionary transitions described in Chapter 2. In most primate species, members of groups cooperate to a degree but are also each other’s main rivals. Our ancestors became evolution’s newest major transition through the ability to suppress disruptive self-serving behaviors within groups, so that between-group selection became the dominant evolutionary force. Teamwork is the signature adaptation of our species. Teamwork includes physical cooperation such as hunting, gathering, childcare, defense against predators, and offence and defense against other human groups. Teamwork also includes mental cooperation, including maintaining an inventory of symbols with shared meaning and transmitting large amounts of learned information across generations. Cultural evolution is a multi-level process, no less than genetic evolution, leading to the mega-societies of today. The concept of human society as like a single organism has a venerable history as a metaphor, but now it stands on a stronger scientific foundation than ever before.

Chapter 5: Psychological Altruism. The previous chapters were required to make sense of altruism defined in terms of action. The distinction between proximate and ultimate causation in evolutionary theory can make sense of altruism defined in terms of thoughts and feelings. Ultimate causation refers to the environmental forces that act upon heritable variation, winnowing certain traits from many other traits that could have existed. Proximate causation refers to the mechanistic basis of any given trait that evolves. Human thoughts and feelings are proximate mechanisms, resulting in actions that are winnowed by natural selection. Proximate and ultimate causation stand in a many-to-one relationship. Just as there are many ways to skin a cat, any given altruistic act can be caused by more than one set of thoughts and feelings. It is important to know the motives of a social partner to predict how he or she will behave in the future, but insofar as two sets of motives result in the same suite of behaviors over the long term, there is no reason to prefer one over the other, any more than we care much whether a person who owes us money pays by cash or check. Proximate mechanisms that cause people to behave altruistically, defined in terms of action, need not qualify as altruistic, defined in terms of motives. Part of taking cultural evolution seriously means that the same altruistic actions might have different psychological motivations in different cultures. The fate of any given psychological mechanism that leads to altruistic action depends critically on the environment, including the human-constructed environment.

Chapter 6: Altruism and Religion. The secular utility of religion, as Emile Durkheim put it, has been debated ever since religion became the subject of scholarly debate, but the study of religion from an evolutionary perspective has established its secular utility better than ever before. In other words, most enduring religions do an impressive job fostering altruism, defined in terms of action, among members of religious communities. Surprisingly, however, altruism defined in terms of thoughts and feelings is foreign to the imagination of most religions. Instead, religious narratives tend to portray normative behaviors as good for everyone and deviant behaviors as bad for everyone. This portrayal is more motivating and leads to more decisive action than puzzling what to do when a behavior is good for self and bad for others or good for others or bad for self. This begins to explain why the word altruism didn’t exist until it was coined by the humanist philosopher Auguste Comte in 1851, as a way to portray his “Religion of Humanity” as morally superior to the Christian doctrine of original sin and salvation through Christ.

Chapter 7: Altruism and Economics. The concept of the invisible hand in economics, which posits that a society can function well without anyone having the welfare of the society in mind, poses one of the strongest challenges to the question of whether altruism does or should exist (e.g, whether it should be replaced by a price system that relies on self-interest and does a better job of organizing large-scale society). The idea that the unregulated pursuit of self-interest robustly benefits the common good is absurd from a multilevel evolutionary perspective. Nevertheless, nature offers outstanding examples of the invisible hand in the form of societies that function well because they are units of selection (e.g., multicellular organisms or social insect colonies) without their members having the welfare of the society in mind (e.g, cells and social insects, which don’t even have minds in the human sense of the word). When applied to human societies, this view of the invisible hand leads to the robust conclusion that policies must be formulated with the welfare of the society in mind, even if the proximate mechanisms that are selected do not require having the welfare of society in mind.

Chapter 8: Altruism in Everyday Life. The broad conception of altruism mapped out in this book can also be called “prosociality”—any attitude, behavior, or institution oriented toward the welfare of others and society as a whole. Abstract arguments about the invisible hand in economics can be brought down to earth by considering individual differences in prosociality in real-world environments such as city neighborhoods, schools, and workplaces. Converging lines of evidence suggest that prosociality is a master variable for human welfare. Being surrounded by highly prosocial people results in multiple assets. Being surrounded by people who are low in prosociality results in multiple deficits. Highly prosocial people are vulnerable to exploitation by people low in prosociality, however, and most people are conditional in their expression of prosociality. In other words, the basic dynamic of multilevel selection plays itself out in everyday life, with the conditional expression of behaviors occupying a role that is roughly analogous to genetic evolution. Hence, the same social environments that would result in the genetic evolution of prosociality also result in the expression of prosociality among behaviorally flexible people. Knowing this is profoundly useful for public policy formulation.

Chapter 9: Pathological Altruism. It is common to think that selfishness comes in good and bad forms but that only good can come from altruism. As soon as we begin thinking about altruism as a social strategy that can evolve under some circumstances but not others, then it becomes obvious that altruism, too, can have pathological consequences. Counseling someone to be altruistic when they live in a social environment that does not favor altruism is like declawing an alley cat. It is the alley (i.e., the social environment) that needs to be changed. Altruistic thoughts and feelings can result in pathological outcomes when evaluated in terms of actions, such as negative codependency. Then we have the basic dynamic of multilevel selection, which causes altruism expressed within lower-level units to become disruptive for higher-level units (e.g., terrorism). These pathologies remind us that altruism is worth wanting only to the extent that it leads to prosocial outcomes at a planetary scale.

Chapter 10: Planetary Altruism. Altruism exists—in the form of traits that evolve by virtue of benefitting whole groups, as a criterion that people use to select their behaviors and public policies, and as a broad family of thoughts and feelings that cause people to agree with a statement such as “I think it is important to help other people.” Yet, this book has been critical of some ways that altruism is traditionally studied. Philosophical discussions and psychological research often place too much emphasis on defining altruism in terms of proximate mechanisms (thoughts and feelings) when a more fully rounded approach is needed that includes proximate causation, ultimate causation, and their many-to-one relationship. Philosophers rely excessively on their own intuition, as if what they regard as altruistic is likely to be culturally universal, whereas cultural variation in proximate mechanisms is expected from an evolutionary perspective. The more fully rounded conception of altruism outlined in this book is needed to solve the problems of modern existence, which require functional organization at the planetary scale. Key insights are that the design principles required for group-level functional organization are scale-independent and that policies that benefit the planet must be selected with the welfare of the planet in mind. In our role as policy selectors, we must become planetary altruists.