Key Terms

Core Ideas

Effective altruism: Effective altruism (EA) is the name of a growing social movement and an idea – that of using evidence and reason to find the most effective possible ways of doing good in the world. An effecitve altruist is someone who identifies with and acts according to the concept of effective altruism.

Cost-effectiveness: The cost-effecitveness of a charitable intervention refers to its marginal impact per dollar. For example, each marginal dollar donated to SCI pays for about 1.8 deworming treatments.

Impartiality: Impartiality is the valuing of all human lives equally, independent of location, age, gender, etc.

Cause-indifference: One is cause-indifferent if one differentiates between charities only based on how the charities contribute to good in the world. That is to say, one does not have a “pet cause.”

Prioritization: Causes can be categorized according to their scope (how much good or bad they do) and their tractability (how easy they are to improve).

Counterfactual reasoning: Counterfactual reasoning is a method of deciding between actions by looking at the expected outcome in each case. For instance, one might consider how some intervention performs compared to a control.

Leveraging donations: Sometimes, charitable donations can be leveraged to increase their effect. For example, instead of donating $1000 to charity, one might use the $1000 to hold a fundraiser event which results in the donation of more than $1000.


Consequentialism: Consequentialism is the view that moral claims only depend on consequences or states of the world. That is, a consequentialist believes that the extent to which an act is good or bad depends solely on the extent to which the states of the world it causes are good or bad. Most effective altruists are consequentialists. Moral philosopher and effective altruist Thomas Pogge is one notable exception; he ascribes to a deontological system of ethics (one in which people have duties to do or not do certain actions).

Utilitarianism: Utilitiarianism is a particular consequentialist moral theory, which states that an act is good or bad according to the extent to which it increases happiness and decreases suffering. Different variations of utilitarianism define happiness and suffereing in different ways; for instance, preference utilitarianism defines happiness (resp. suffering) as the fulfilment (resp. denial) of one’s desires or preferences, whether or not this leads to pleasure. Many EAs ascribe to some form of utilitarianism.

Population ethics: Population ethics asks questions about the relative importance of different sentient beings or groups of sentient beings. Its important questions include: What is the moral status of non-human animals? What is the moral status of not-yet-born humans? Is the total amount of humans with good experiences morally relevant, or does only their average happinness matter? Population ethics is a source of significant disagreement among effective altruists.

Rationalism: Rationalism is the view that reason and experience / evidence, rather than religious belief and emotional responses, should be the basis of one’s actions and opinions.

Moral realism: Moral realism is the claim that morality exists as more than just a human construct, in the same way that most people think of the external world existing independent of humans to perceive it. By contrast, moral non-realism is the claim that morality is just an idea that humans like to talk about.

Actions and term-requiring causes

Earning to give: Earning to give refers to the practice of choosing a career not for its direct impact but for its salary, and then donating a significant portion of this salary to effective charities. Earning to give can be more effecitve than direct work because money is flexible, because earning to give is irreplaceable (someone else will sometimes do the direct impact job if you don’t), and because it allows individuals to specialize in what they are best at. Many effective altruists earn to give.

Pledge (GWWC & TLYCS): Many effecitve altruists sign pledges to donate a significant portion of their incomes to charity. Members of Giving What We Can pledge at least 10% of their income to effective charities to relieve the suffering caused by extreme poverty. TLYCS has a similar pledge. A more general pledge is available at

X-Risk: An existential risk is a danger that is global in scope and terminal in intensity. That is, it threatens to “either annihilate Earth-originating intelligent life or permanently and drastically curtail its potential.” Examples include severe climate change, nuclear warfare, and unfriendly artificifial intelligence.

Meta-EA: A meta-EA charity is an organization which contributes indirectly by seeking to build the effective altruism movement or increase its efficiency. Examples include GiveWell, CEA, TLYCS, and MIRI.