This lack of utility is not due to any technical oversight. Rather, it arises from the attempt to extend Hamilton’s rule to every instance of natural selection. This impulse is understandable, given the intuitive appeal of Hamilton’s original formulation. However, the power of a theoretical framework is derived from its assumptions, thus a theory with no assumptions cannot predict or explain anything. As Wittgenstein argued in his Tractatus Logico-Philosophicus, any statement that is true in all situations contains no specific information about any particular situation.
There Is No Universal Design Principle
The concept of inclusive fitness arises when one attempts to explain the evolution of social behavior at the level of the individual. For example, inclusive fitness theory seeks to explain the existence of sterile ant workers in terms of the behaviors of the workers themselves. The proposed explanation is that workers maximize their inclusive fitness by helping the queen rather than producing their own offspring.
The claim that evolution maximizes inclusive fitness has been interpreted as a universal design principle for evolution. This claim is based on an argument by Hamilton that evolution maximizes the mean inclusive fitness of a population, and a separate argument by Alan Grafen that evolved organisms act as if to maximize their inclusive fitness. Both of these arguments depend on restrictive assumptions, including additivity of fitness effects. Because experiments have shown that fitness effects in real biological populations are nonadditive, these results cannot be expected to hold in general. Moreover, both theory and experiment have shown that frequency-dependent selection can lead to complex dynamic phenomena such as multiple and mixed equilibria, limit cycles, and chaotic attractors, ruling out the possibility of general maximands. Thus, evolution does not, in general, lead to the maximization of inclusive fitness or any other quantity.
Commonsense Approaches to Evolutionary Theory
Fortunately, no universal maximands or design principles are needed to understand the evolution of social behavior. Rather, we may rely on a straightforward genetic approach: Consider mutations that modify behavior. Under which conditions are these mutations favored (or disfavored) by natural selection? The target of selection is not the individual, but the allele or the genomic ensemble that affects behavior.
To investigate these questions theoretically, one needs modeling assumptions. These assumptions can be highly specific, applying only to particular biological situations, or broad, applying to a wide range of scenarios. Modeling frameworks that rely on general (yet precise) assumptions have recently emerged as a powerful tool for studying the evolution of populations structured spatially, by groups, and physiologically; the evolution of continuous traits; and inclusive fitness theory itself (in cases where fitness effects are additive and other requirements are satisfied). Although these frameworks can be used to obtain general results, none of them is universal or assumption-free. Instead, they draw upon their assumptions to make well-defined, testable predictions about the systems to which they apply.
Discussion
Inclusive fitness theory attempts to find a universal design principle for evolution that applies at the level of the individual. The result is an unobservable quantity that does not exist in general (if additivity is required) or has no predictive or explanatory value (if the regression method is used). If instead we take a genetic perspective and ask whether natural selection will favor or oppose alleles that modify social behavior, there is no need for inclusive fitness.
The dominance of inclusive fitness theory has held up progress in this area for many decades. It has consistently suppressed reasonable criticism and alternative approaches. In particular, the attempt to eschew the requirement of additivity using regression methods has led to logical obfuscation and false claims of universality. Reasonable inclusive fitness calculations that assume additivity represent an alternative method to account for fitness effects in some limited situations, but this method is never necessary and often needlessly complicated. There is no problem in evolutionary biology that requires an analysis based on inclusive fitness.
Having realized the limitations of inclusive fitness, sociobiology now has the possibility to move forward. We encourage the development of realistic models grounded in a firm understanding of natural history. With the aid of population genetics, evolutionary game theory, and new analytic procedures to be developed, a strong and resilient sociobiological theory can emerge.
Acknowledgments
I am grateful to John Taylor (Ike) Williams for his unwavering support and advice, to Robert Weil for his editorial guidance on this as on my earlier books published by W. W. Norton, and to Kathleen M. Horton for her invaluable assistance in research, editorial work, and manuscript preparation.
Chapter 2, “Solving the Riddle of the Human Species,” is a modification of the author’s “The Riddle of the Human Species,” in The New York Times Opinionator, February 24, 2013. Chapter 3, “Evolution and Our Inner Conflict” was modified from an article of that name by the author, in The New York Times Opinionator, June 24, 2012. Chapter 11, “The Collapse of Biodiversity,” is a modified version of “Beware the Age of Loneliness,” in The World in 2014, The Economist, November 2013, p. 143.
Index
Page numbers listed correspond to the print edition of this book. You can use your device’s search function to locate particular terms in the text.
Absolute Paradox (Kierkegaard), 157–58
academia, Harvard, 40–41
Age of Loneliness (Eremocene), 123
alien life, 45, 53–55, 102–4, 106
Allen, Benjamin, 74, 189–202
allomones, 81–82
anole lizards, 138
Antarctica, life, 104
Anthropocene, 123
anthropocentricity, 42–43
ants, 65, 83, 86–88, 95–97, 166
arachnophobia, 139–40
archaeans, 47, 104, 108, 111
artificial life, 58
australopiths, 175
Bacon, Francis, 38, 133, 136
bacteria, communication, 89 see also microbes
BAM (Brain Activity Map), 163–64
biodiversity, 46–50, 123–32
biosphere, 46–50
bird song, 81
BNR (biology, nanotechnology, robotics), 58
brain, human,see mind
Bruller, Jean, 135
campsites, 21–22
Carlson, Anton J., 153
causation, proximate versus ultimate, 15
chimpanzees, 175
Churchland, Patricia, 161
confliction, moral, 27–34
confabulation, 167–68
conquest of galaxy, 119–22
conscience, origin, 27–34, 179–80
consciousness, 159–70
consilience (unity of knowledge), 35–75
continuum, concept, examples, 44–52, 167, 186
cooperation, origin, 21–22, 29–31
Copernicus, 46
Creationism, 183–85
creation stories, 12, 18, 151–58, 181–85
creative arts, 17, 22, 35–75, 79, 186
culture, origin, 37–75, 80, 100, 105, 141–46
Darwin, Charles, 29, 162–63, 178, 183
Dawkins, Richard, 70, 73
Deinococcus, 104–5
Dennett, Daniel, 161
driver ants, 92–94
driving forces of evolution, 23–24, 61–75, 189–202
dysfunction, innate human property, 176–80
ecosystems, 105, 120, 124–26, 144
Edelman, Gerald, 159
emergent evolution, 165
emotion, 167 see also mind; phobias
Enceladus, 105–6
Enlightenment, 37–40, 51–52
Eremozoic Era, 123
E.T., 104–22
eugenics, 58–59
Europa (moon of Jupiter), 106
eusociality, 18–20, 61–75
in humans, 20–21, 61–7
5, 189–202
evil, 27, 179
evolution, driving forces, 23–24, 61–75, 189–202
existential conservatism, 60
exoplanets, 44–46, 102–9
extinction, 127–32
extraterrestrial life, 102–22
extremist, religion, 154–55
extremophiles, 104–6, 109
faith, religious, 151–58
fishes, electric, 49–50
forces, evolution, 23–24, 61–75, 189–202
Founding Fathers, U.S., 155–56
free will, 159–70
Galileo, 46
gene-culture coevolution, 56
God, 31, 33–34, 148–50
gods, Greek, 43
gossip, 142
habitat, selection, 143–46
Haldane, J. B. S., 66–69
Hamilton, William D., 67–70, 189–202
Hamilton inequality, 67–70, 189–202
Harvard University, faculty, 40–41
hearing, 48
history of life, 56 see also human prehistory
Hofstadter, Douglas, 166
honeybees, 100
human evolution, 17–26, 43, 58–59, 111
Human Genome Project, 163
humanities, definition, 17, 35–75, 174
humanity, as dysfunctional species, 176–79
human nature, 136–37, 143–46
human prehistory, 17–26, 74–75, 80, 89–90, 111, 175–76
Human Relation Area Files, 143
IF theory (inclusive fitness theory),see forces, evolution
inclusive fitness,see forces, evolution
instinct, 29–31, 100–101, 135–46
human, 139–46
Kepler space telescope, 106
keystone species, 126
Kierkegaard, Søren, 157
kin selection,see forces, evolution
kitten, instinctive play, 43–44
leafcutters, ants, 97–99
Lewis, C. S., 157
Madison, James, 156
mathematics, 142
meaning of “meaning,” 12–16
memory, origin, role, 22–23
microbes, 102–9
microorganisms, 102–9
mind, 24, 159–70
see also creative arts; culture, origin; Enlightenment; human nature; instinct; pheromones; phobias; senses, human; social intelligence
mole rats, 32, 111
monkeys, 42–43, 114, 175
moral reasoning, 40
Mormonism, 156
moths, pheromones, 48, 84
music, antiquity, 147–48
natural selection, 13–14, 18–19, 28–29
nematodes (roundworms), 105, 125
neuroscience of religion, 148
Nietzsche, Friedrich, 12
Nowak, Martin A., 72–75, 189–202
pangenesis (microbial space travel), 108–9
Paul (prophet), 11
pheromones, 79–91
phobias, 139–42
picozoans, 47, 48, 104, 111
Pius XII, Pope, 153
plants, communication, 88–89
Pledge of Allegiance, U.S., 156
poetry, origin, nature, 41–43
pollinators, social, 100
prehistory, human, 32–34
proximate causation, 15
qualia, 161
racism, 31
religion, 31, 40, 147–58
robots, 33, 58–59, 106, 118, 121
Romney, Mitt, 156
Sagan, Carl, 27
Satan, 33, 183
science, qualities, relation to humanities, 17–18, 44–75
selection forces, evolution, 23–24, 61–75, 189–202
selection, group, 23–24, 29–30
selection, multilevel, 23–24
selection, natural, 14, 18–19, 28–29
selection, volitional, 14
Seneca the Younger, 153
senses, human, 48–50
sin, 30–34, 175–76
SLIMES (deep biosphere), 105
smell, 49, 79–91
snakes:
olfaction, 85
phobia, 141
social intelligence, 22, 23, 30, 32, 43, 75, 116
social networks, 30
soul,see mind; religion
sound, communication, 81
spiders, 93, 105, 116, 125, 139–41
spirituality, 148–55
stickleback (fish), 137–38
storytelling, 167–68
success, of ants and termites, 99
superorganisms, 92, 165–66
Tarnita, Corina, 72–74
taste, 49–75, 79–91
taxonomy, 125–26
Teresa of Ávila, Saint, 147
termite societies, 166
theology, 148–49
tolerable parasite load, human, 180
tribalism, 150–54
turtles, instinct, 138–39
ultimate causation, 15
unification, science and humanities, 12, 35–75
Vercors (Jean Bruller), 135
virtue, 30–34
viruses, 47, 104, 108, 111
vision, 48–49
volitional selection, 14, 59 see also other forms under selection
Vostok, Lake, 106
war, 154–55
warning coloration, 81–82
Washington, George, 156
About the Author
EDWARD OSBORNE WILSON is generally recognized as one of the several leading biologists in the world. He is acknowledged as the creator of two scientific disciplines (island biogeography and sociobiology), three unifying concepts for science and the humanities jointly (biophilia, biodiversity studies, and consilience), and one major technological advance in the study of global biodiversity (the Encyclopedia of Life). Among more than one hundred awards he has received worldwide are the U.S. National Medal of Science, the Crafoord Prize (equivalent of the Nobel, for ecology) of the Royal Swedish Academy of Sciences, the International Prize of Biology of Japan; and in letters, two Pulitzer Prizes in nonfiction, the Nonino and Serono Prizes of Italy, and the COSMOS prize of Japan. He is currently Honorary Curator in Entomology and University Research Professor Emeritus, Harvard University.
ALSO BY EDWARD O. WILSON
A Window on Eternity: Gorongosa National Park, Mozambique (2014)
Letters to a Young Scientist (2013)
Why We Are Here: Mobile and the Spirit of a Southern City,
with Alex Harris (2012)
The Social Conquest of Earth (2012)
Kingdom of Ants: José Celestino Mutis and the Dawn of Natural History in the New World, with José M. Gómez Durán (2011)
The Leafcutter Ants: Civilization by Instinct, with Bert Hölldobler (2011)
Anthill: A Novel (2010)
The Superorganism: The Beauty, Elegance and Strangeness of Insect Societies,
with Bert Hölldobler (2009)
The Creation: An Appeal to Save Life on Earth (2006)
Nature Revealed: Selected Writings, 1949–2006 (2006)
From So Simple a Beginning: The Four Great Books of Darwin,
edited with introductions (2005)
Pheidole in the New World: A Dominant, Hyperdiverse Ant Genus (2003)
The Meaning of Human Existence Page 13
