Good is an adjective that means pleasing, favorable, or acceptable: “a good article”; a “good job”; a “good book”. It is also a noun that means an advantageous result or effect: a good deal; a good time; a good meal. It is a common form of adverb after verbs like go, feel, sound, look, and do: “I had a very good time”; “he did well on the test”. In some contexts, it can be used as a predicate adjective: “She is a good seamstress”.

It is also a word that means morally positive or upstanding: a good person; “a good citizen”.

Whether something is good for oneself is the underlying question in most ethical discussions. It is thus natural that many philosophers have been keen to develop theories about the good for a person or group of people. The interest in this question gained momentum in the wake of G. E. Moore’s publication of Principia Ethica in 1903; with it, the study of ethics took a turn toward conceptual analysis.

Many philosophical approaches have been developed in response to Moore’s challenges. Some, such as Franz Brentano, sought to present analyses of the good that were halfway between Moore’s naturalism and his rejection of it. Others, such as Peter Geach and J. L. Austin, were critical of Moore’s attempts to make the good into a metaphysical entity.

Another issue with the idea of a good for a person is that it can be difficult to determine what exactly is good for someone. For example, some activities that are good for a person can appear bad for another person, or vice versa. This is a challenge to the idea of an objective moral standard and makes it hard to determine whether or not a given action is, on balance, a good thing to do.

For this reason, some people have opted to define the concept of a good in terms of its utilitarian value. The advantage of doing this is that it removes the need to attempt to articulate an abstract standard for what the good is and makes the concept more readily identifiable in concrete, human terms.

The concept of a good has also been extended to include a number of environmental and other “common-pool” resources. The global atmosphere, a large ocean, and countless other natural resources are examples of goods that, in the case of the global atmosphere at least, are both easy to subtract from and hard to exclude from society as a whole. This sort of good is sometimes called an anti-rivalrous good. By contrast, some of the goods that are consumed as a result of private ownership (e.g., goods that are sold in a shop) are often referred to as rivalrous good. The distinction between these two types of goods is important for understanding the economics of resource consumption and allocation. A more general version of the anti-rivalrous good is called a non-rivalrous good, which includes both private and public goods.