In its most general context of the study of morality, ethics, religion and philosophy, the good often refers to and denotes that conduct which is to be preferred and prescribed by society and its social constituents as beneficial and useful to the social needs of society and its preferred conventions. The specific meaning and etiology of the meaning and use of the 'good' and its associated translations among ancient and contemporary languages has varied substantially in its inflected meaning depending of circumstances of place, history, religious context and philosophical context.
In religion, ethics, and philosophy, "good and evil" is a very common dichotomy. In cultures with Manichaean and Abrahamic religious influence, evil is usually perceived as the antagonistic opposite of good. Good is that which should prevail and evil should be defeated. In cultures with Buddhist spiritual influence, this antagonistic duality itself must be overcome through achieving Śūnyatā, or emptiness. This is the recognition of good and evil not being unrelated, but two parts of a greater whole; unity, oneness, a Monism.
A significant enlightenment context for studying the 'good' has been its significance in the study of "the good, the true and the beautiful" as found in Immanuel Kant and other Enlightenment and Renaissance philosophers and religious thinkers. These discussions were undertaken by Kant particularly in the context of his second Critique of Practical Reason within his Three Critiques.
Every language has a word expressing good in the sense of "having the right or desirable quality" (ἀρετή) and bad in the sense "undesirable". A sense of moral judgment and a distinction "right and wrong, good and bad" are cultural universals.
Although the history of the origin of the use of the concept and meaning of 'good' are diverse, the notable discussions of Plato and Aristotle on this subject have been of significant historical effect. The first references that are seen in Plato's The Republic to the Form of the Good are within the conversation between Glaucon and Socrates (454 c–d). When trying to answer such difficult questions pertaining to the definition of justice, Plato identifies that we should not “introduce every form of difference and sameness in nature” instead we must focus on "the one form of sameness and difference that was relevant to the particular ways of life themselves” which is the form of the Good. This form is the basis for understanding all other forms, it is what allows us to understand everything else. Through the conversation between Socrates and Glaucon (508 a–c) Plato analogizes the form of the Good with the sun as it is what allows us to see things. Here, Plato describes how the sun allows for sight. But he makes a very important distinction, “sun is not sight” but it is “the cause of sight itself.” As the sun is in the visible realm, the form of Good is in the intelligible realm. It is “what gives truth to the things known and the power to know to the knower”. It is not only the “cause of knowledge and truth, it is also an object of knowledge”.