The Descent of Man | Study Guide

Charles Darwin

Download a PDF to print or study offline.

Study Guide
Cite This Study Guide

How to Cite This Study Guide

quotation mark graphic


Course Hero. "The Descent of Man Study Guide." Course Hero. 4 Jan. 2019. Web. 23 June 2021. <>.

In text

(Course Hero)



Course Hero. (2019, January 4). The Descent of Man Study Guide. In Course Hero. Retrieved June 23, 2021, from

In text

(Course Hero, 2019)



Course Hero. "The Descent of Man Study Guide." January 4, 2019. Accessed June 23, 2021.


Course Hero, "The Descent of Man Study Guide," January 4, 2019, accessed June 23, 2021,

The Descent of Man | Chapter 4 : Comparison of the Mental Powers of Man and the Lower Animals, continued | Summary



In this chapter Darwin continues the examination of the mental powers of humans and lower animals begun in Chapter 3, though here he focuses more on the moral sense and the importance of sociability and community in humans and animals. He believes that humankind's moral sense and conscience are most important. The idea of ought sums up the moral inclination in humankind, and notions of duty and sacrifice are defined by what communities and individuals believe should be done or how members should act. According to Darwin, any animal with a certain level of intellectual capacity will acquire a moral sense by the development of sympathy for others. Past actions can be recalled in the brain and can evoke specific emotions. With the use of language members of the community create agreed-upon ideas about behavior (Darwin's ought). Darwin states that no animal, no matter how advanced, would have the same moral sense as humankind, though animals do have understood ideas about right and wrong.

Both humans and animals are social by nature and perform many services for one another, such as warning of danger, sharing food, hunting in packs, defending, cleaning, and caring for each other. It's unclear to Darwin the extent that lower animals have feelings for others in their group: some will expel (or even kill) wounded members, and others will protect the wounded in the group. Darwin believes animals do possess sympathy, and he cites as evidence a crow that helped to feed a blind pelican and a baboon that protected a fellow member from human punishment. He also notes that animals do exhibit love (for one another and for their masters in domestic cases), and the fact that they socialize suggests they get some sense of pleasure or satisfaction from it. For humans and animals, Darwin suggests, social instincts are developed in the young by remaining with their parents for a certain amount of time. Even the lowest of animals, such as starfish, spiders, and earwigs, exhibit some kind of parental affection toward their young. While Darwin says it's impossible to say that social instincts are a result of natural selection, he does suggest that characteristics such as courage may be connected to natural selection.

Humans are a social animal that dislikes solitude, beginning with the family unit and extending to immediate communities and beyond. Social instincts are influenced by community and have varying degrees of importance. For example, a group will fight to protect one of its members but may be indifferent to the plight of a member of another group. Similarly, mothers will risk danger for their children but not for a stranger's child. Darwin points out that the social instinct can reach beyond the immediate group—why would a stranger jump into a lake to save another stranger if not for the strength of the social instinct? This leads Darwin into a discussion of why a human regrets, which he says is a result of the ought (or should) instinct in a community. Humans are concerned about what others think of them—a result of sympathy—and may regret some action because they want approval from the community. Humans will resolve to act differently in the future to avoid the regret (or shame), and this is where Darwin suggests conscience comes into play. Darwin does not answer his own question as to whether animals can feel regret, though he does cite clear instances where dogs appear to show shame for unacceptable behavior.

Social virtues can vary between communities and at different times. Darwin asserts that no tribe or society could survive if murder, robbery, and treachery were common and allowed. But actions such as scalping enemies among North American Indians and the honorable act of committing suicide in some societies are acceptable. Slavery, he notes, was beneficial for some in ancient times but is viewed as a crime only as recently as the 18th century. A standard of morality, according to Darwin, is based on the general good or welfare of the community, and the "law of honor" is the socially agreed-upon guide of conduct (breaking that law results in shame).

Darwin closes this chapter with a brief summary of the most significant points from both Chapters 3 and 4:

  • The difference between the lowest man and the highest animal is immense.
  • The difference between humans and the highest animals is great but measured by degrees.
  • Humans and animals both possess senses, intuition, love, memory, and reason.
  • Language is the most important differentiation between human and animal.
  • A moral sense distinguishes humans from animals; the Golden Rule (do to others as you would have others do to you) is the foundation of that morality.


Darwin examines the nonphysiological similarities and differences between humans and animals to further illuminate his theory of evolution and natural selection. In Chapter 3 he discussed the mental faculties of the two; in this chapter he's focused on the social and moral characteristics.

By presenting similarities in action and social organization, Darwin attempts to show how the structural connections between humans and mammals are reflected in their behavior, implying that related physical development has a connection to how mammals act. While he makes it clear that intellect and language abilities are what set humans far above most animals, the moral sense (or conscience) of humans remains connected by degrees to lesser animals. The importance of sympathy in understanding others is key to Darwin's analysis because it aids in the creation of community, which both humans and animals engage in. According to Darwin, sympathy and community produce a moral standard that society lives by—a concept that his readers can understand no matter how skeptical they are of his natural selection theory. The fact that animals, who share an early progenitor form with humans, exhibit similar—though not as advanced—emotions such as sympathy helps to support Darwin's theory of comparable evolution.

Cite This Study Guide

information icon Have study documents to share about The Descent of Man? Upload them to earn free Course Hero access!