Philosophy 152 - 8.3.3 Natural and Human Foundations for Moral Values

Different ethical frameworks rest on different foundations or justifications: some appeal to a nonhuman principle like nature; others appeal to shared human institutions like culture, tradition, society, or law; and still others appeal to the individual and their resources for moral reasoning. This section examines moral reasoning based on nature, society, politics, the self, or reason.

Nature and Natural Law

One approach to ethics appeals to nature or natural law to make claims about what is good or bad. An action, goal, or characteristic is good if it accords with nature or natural law and is bad if it violates it. Here, nature can refer to human nature or the observed features of the natural world.

According to the medieval philosopher Thomas Aquinas (1225–1274), there are four types of laws: eternal, natural, human, and divine. Eternal laws govern the universe, natural laws govern the natural world, and human laws govern human societies. Divine laws are supernatural and allow humans to reach salvation but cannot be known through human reason alone. Instead, they must be revealed by God (e.g., the Ten Commandments, Scriptures, and other divine revelations). Humans can use reason, however, to discover natural laws and create human laws. For Aquinas, human laws must align with natural law. Human laws that violate the laws of nature are “no longer a law but a perversion of law” (Aquinas [1485] 1948, 649). Aquinas’s argument contributes to classical natural law theory, which sees laws as upholding natural order. Because nature is not subjective, natural law theory sees values as objective.

Ethical Naturalism

As discussed earlier, some philosophers believe that an essential link between values and telos, or purpose, creates an objective moral reality. Ethical naturalism argues that performing good actions fulfills human nature, while performing evil actions distorts it. If this is the case, moral values and “what is good” are based on natural facts about the world, not individuals’ subjective feelings or beliefs. Ethical naturalism often relies on concepts of pleasure, desire, happiness, or flourishing to define what is naturally good or bad.

The 20th-century philosopher Philippa Foot (1920–2010) provides one of the most famous philosophical arguments for ethical naturalism. In Natural Goodness (2003), Foot argues that moral values like “goodness” are not about statements, as G. E. Moore suggested in Principia Ethica, or about mere emotions that individuals feel, but are instead about human flourishing. Just as bees have qualities that help them thrive and build strong colonies, so humans have virtues that help them to thrive in life and build flourishing communities. Foot’s description of flourishing is influenced by Aristotle, who based his concept of ethics on an examination of different virtues, which involve fulfilling one’s telos, or purpose. This approach to morality is called virtue ethics. In ethical naturalism and virtue ethics, discovering moral values requires understanding one’s nature, which must be based on an objective understanding of human life.


The chapter on normative moral theory explores virtue ethics in greater depth.

In Natural Goodness, Foot further argues that moral evaluations are similar to the types of evaluations that people make about other living things in the natural world. Moral goodness describes how one should live according to human nature. Just as you can know what is good for an animal by studying its nature, you can know what is good for humans by understanding their nature.

More importantly, Foot argues that part of understanding what an organism is involves knowing what is good for it based on its vital processes. For example, you know what is good for a duck based on knowledge of what a duck is. This knowledge would include an understanding of the duck’s nature and what helps it live a good life. A duck is an aquatic bird, so a habitat with water will be good for it. Along similar lines, you can know what is good for a human based on knowledge of human nature.

In this sense, she connects morality to biological flourishing, or achieving the goals of human life. For example, if the purpose of human life is to develop meaningful relationships and to actualize one’s potential, then morality is based on the virtues that allow someone to achieve these ends. For example, one could argue that humans, like other primates, have evolved to cooperate and care for others as a part of their survival, so actions that promote cooperation and care are good, and actions that harm others are bad.


Some ethical theories focus exclusively on certain human capacities, like reason. Reason is a methodical way of thinking that uses evidence and logic to draw conclusions. The use of reason as the grounds for morality became particularly important in Enlightenment philosophy because philosophers wanted to assert the validity of moral principles without relying on religious beliefs or God.

A printed engraving shows the head and shoulders of a person wearing a short powdered wig. The portrait appears in an oval frame atop a pedestal that reads Immanuel Kant.
Figure 8.5 Enlightenment philosopher Immanuel Kant argued that an action is moral if it can be universal. (credit: “Bildnis des Immanuel Kant” by Johann Friedrich Schleuen (senior)/Leipzig University Library, Public Domain)

The Enlightenment philosopher Immanuel Kant (1724–1804) argued that as rational agents, humans express general principles or maxims when they act. You always act for a reason—namely, a goal or end in mind. For Kant, an action or decision is moral if you can universalize it, which he formulates in the categorical imperative. Kant’s categorical imperative states: “Act only according to that maxim whereby you can, at the same time, will that it should become a universal law” (Kant [1785] 1998, 31). That means you know an action is moral if can be universal for everyone. The categorical imperative works best when we note that an action contradicts it. For example, lying cannot be moral because it is not universalizable. It is impossible for everyone to lie. Even the act of lying assumes that people usually tell the truth.


Other approaches to ethical theory argue that morality originates in the self. How do people know what is right or wrong? What motivates them to be good and care for others? Some argue that the conscience, an individual’s inner sense of right and wrong, forms the basis for ethics. But where does one get this inner sense? Some argue that it comes through intuition—cognition that seems completely self-evident and impossible to deny—while others assert that individuals develop it through education or reason.

Other approaches to ethics rely upon the individual’s psychology, moral sentiments, or feelings. Multiple moral theories emphasize compassion and empathy, the ability to suffer with and share others’ feelings. For the ancient Chinese philosopher Mencius (371–289 BCE), the feeling of compassion allows benevolent actions, which are the basis for ethics and well-being. Compassion and empathy might also be considered virtues that individuals cultivate. Virtue ethics bases its moral theory on virtues as personal characteristics that an individual can develop.

Feminist care ethics bases ethics on individuals’ feelings for the people who play a significant role in their lives. In her book Caring: A Feminine Approach to Ethics and Moral Education, the American philosopher Nel Noddings (b. 1929) argues that an “ethics built on caring” is “characteristically and essentially feminine” insofar as it arises out of women’s experiences, which are traditionally defined through caregiving roles (2013, 8).

An important debate within ethical theory is the importance of altruism, which is the selfless care for others’ well-being. Some moral philosophers argue that only altruistic actions are completely moral, while others assert that self-interest can motivate the moral treatment of others. It is this issue that the next section addresses.

Think Like a Philosopher

In the above section, you learned that there are many different possible sources for moral knowledge. Do you think there are objective sources of moral knowledge? Why or why not?

The content of this course has been taken from the free Philosophy textbook by Openstax