1. Deontology—branch of ethics which is duty-based. A person who adapts a deontological approach to ethics follows certain laws and makes ethical decisions by adhering to those laws. One judges moral action not by the consequence of the act, but by the act itself.

Associated Philosophers:

• Immanuel Kant—18th century German most famous for his four formulations of the Categorical Imperative. One basic idea from his categorical imperative is that one should abide by a rule only if she could will in good faith that everyone else should follow that rule.

• Christine Korsgaard—21st century neo-Kantian who is most famous for the work Sources of Normativity.

2. Virtue Theory—branch of ethics which defines the ethical by looking at the acts of moral exemplars. A virtue theorist studies the character of individuals along with their im/moral acts. They judge the morality of a person’s act not by just looking at the consequences that resulted from the act, or whether the act fell under a universal law, but look at the intentions of the individual.

Associated Philosophers:

• Aristotle—ancient Greek philosopher who stressed the idea that an individual can achieve eudemonia (happiness, flourishing), phronesis (practical wisdom), and arête (good character) by internalizing the teachings of wise mentors and learning from experience.

• Linda Zagzebski—21st century American virtue theorist who asserts in Divine Motivation Theory that one can identify the good through looking at moral exemplars’ acts. For instance, one may not be able to tell the chemical composition of water, but she can describe its features by feeling it or tasting it. Likewise, a person may not be able to define the ethical, but through observing moral exemplars like Jesus and Gandhi, she can describe aspects of the good.

3. Consequentialism—branch of ethics which bases the ethical upon the beneficial outcomes of an act.

Associated Philosophers:

• Jeremy Bentham—late 18th century Brit who founded utilitarianism and created the happiness principle—the notion that one should give the greatest happiness to greatest number of people.

• John Stuart Mill—19th century British utilitarian who differed from Bentham in that he suggested that there were higher forms of happiness; not all types of happiness are equal. He proclaimed that the greatest happiness comes from intellectual and moral endeavors. His picture is to the right.

• Soren Kierkegaard—19th century Danish philosopher who introduced the idea that within religion and love (issues having to do with moral decision-making) one must take a leap of faith (“teleological suspension of ethics”). No amount of reasoning or experience could ever justify any person to hold a certain belief or romantic affection. For instance, he declared that when God asks Abraham in the book of Genesis to sacrifice his son Issac, Abraham’s decision of faith was beyond logical thinking.

• Friedrich Nietzsche—19th century German who asked the question, “What is the value of moral values?” He argued that there were two lines of morality: master and slave. Master morality, he believed, came from the more physically powerful peoples. These masters, due to their power, asserted that the good came from strength, courage, and noble action. On the other hand, slave-morality originated from the weaker classes. These people particularly valued humility and charity due to their impoverished state.

• Jean-Paul Sartre—20th century French existentialist who asserted that existence precedes essence; or in other words, that a person’s physical existence leads them to determine their essence. People are “condemned to freedom” because they are not born with any pre-existing values; they create them. Sartre also coined the term “bad faith” which he described as the act of denying one’s freedom although the individual partly knows she possesses this freedom. 

• Albert Camus—20th century Frenchman who philosophized about how people deal with the “absurd.” Camus asserted that people know that they will die, which makes them feel life is more precious. Yet, in knowing that one will die and his life work will have no effect upon him, he feels meaninglessness. This paradox is the absurd. 

• Alasdair MacIntyre—21st century American who argues that all moral philosophy after Aristotle is illogical (with the exception of Nietzsche) and has forgotten essential Aristotelian principles. He then goes on to argue that the only way moral theory in the twenty-first century can be rejuvenated (or amended) is to incorporate Aristotelian ethical philosophy.

• David Hume—18th century Scot who asserted that emotion facilitates a person’s ethical decision-making. In addition, he posited the problem of induction and the is-out problem. The problem of induction is that people base conclusions by inductive reasoning through looking at natural trends in nature, and then asserting outcomes by those trends. Yet, the trouble with such inductive thinking is that natural trends may not happen as they have in the future. As for the is-ought problem, he asserted that people often make support ought claims through is-statements. His portrait is to the right.