Throughout the history of philosophy there have been many different conceptions of good. Some, like the eighteenth-century British philosophers Adam Smith and David Hume, tend to identify the good in terms of personal preferences and desires. Others, such as nineteenth-century Social Darwinists like Herbert Spencer and early twentieth-century British moral theorists like W. D. Ross, emphasize the value of good in an evolutionary context and, to some extent, equate it with one’s fitness.

Generally, these accounts are distinguished according to whether they treat the good as something constituted by our preferences or our desires or as an objective feature of the universe. The first of these is often the more orthodox view, as is evident in the work of Plato (c. 428-348 or 347 b.c.e.) and in the metaphysical writings of Thomas Aquinas.

In a more radical development, the existentialist trend has stressed man’s spontaneous decision as the free creation of the good. This is, however, inherently contradictory and the negation of the good in its own terms.

The concept of the good is also used by philosophers to distinguish between a person’s preferences and his or her actual values. This can be a significant distinction, especially in the area of economics.

A second major difference is that some philosophers see the good as a means of something else, such as a beautiful sunset, while others believe that it is a natural end in and of itself. This is often referred to as “intrinsic” versus “extrinsic” good, and can be difficult to reconcile in practice.

Finally, the idea of the good can be found in various forms of philosophical contract theory. For example, John Rawls’s A Theory of Justice (1971) is a prominent work that stresses the role of principles in establishing norms for justice. These principles may, as in the early modern morality of contract theorists, impose constraints on a person’s actions.

These principles may be conceived as independent and absolute, as in Kant’s Critique of Pure Reason, or they might be conceived as able to override purely utilitarian considerations. This can be a critical distinction, as it is often difficult to reconcile the views of utilitarian and deontological philosophers.

Another important distinction in the understanding of good is that some philosophers emphasize that the good is a conscious, rationally determined goal for a person, while others stress the importance of human free will as the primary motivation for moral decisions. This distinction, sometimes referred to as the “Golden Mean,” has been influential in articulating both ethical theories and moral judgments.

For example, the Golden Mean, a central feature of Aristotle’s philosophy of right reason, holds that “right action” is “in accordance with the nature of the person,” as opposed to simply following his “good sense.” St. Thomas, in his doctrine of the Christian life, likewise emphasizes that moral goodness is based on the person’s nature, and the provident Creator guides His creatures toward this good by means befitting their nature.