Summum bonum is a Latin expression meaning "the highest good", which was introduced by the Roman philosopher Cicero, to correspond to the Idea of the Good in ancient Greek philosophy. The summum bonum is generally thought of as being an end in itself, and at the same time containing all other goods.
The term was used in medieval philosophy. In the Thomist synthesis of Aristotelianism and Christianity, the highest good is usually defined as the life of the righteous and/or the life led in communion with God and according to God's precepts. In Kantianism, it was used to describe the ultimate importance, the singular and overriding end which human beings ought to pursue.
Plato's The Republic argued that, "In the world of knowledge the idea of good appears last of all, and is seen...to be the universal author of all things beautiful and right".Silent contemplation was the route to appreciation of the Idea of the Good.
Aristotle in his Nicomachean Ethics accepted that the target of human activity, "Must be the 'Good', that is, the supreme good.", but challenged Plato's Idea of the Good with the pragmatic question: "Will one who has had a vision of the Idea itself become thereby a better doctor or general?". However, arguably at least, Aristotle's concept of the unmoved mover owed much to Plato's Idea of the Good.
Philo of Alexandria conflated the Old Testament God with the unmoved mover and the Idea of the Good.Plotinus, the neoplatonic philosopher, built on Plato's Good for his concept of the supreme One, while Plutarch drew on Zoroastrianism to develop his eternal principle of good.
Augustine of Hippo in his early writings offered the summum bonum as the highest human goal, but was later to identify it as a feature of the Christian God in De natura boni (On the Nature of Good, c. 399). Augustine denies the positive existence of absolute evil, describing a world with God as the supreme good at the center, and defining different grades of evil as different stages of remoteness from that center.
The summum bonum has continued to be a focus of attention in Western philosophy, secular and religious. Hegel replaced Plato's dialectical ascent to the Good by his own dialectical ascent to the Real.
G. E. Moore placed the highest good in personal relations and the contemplation of beauty - even if not all his followers in the Bloomsbury Group may have appreciated what Clive Bell called his "all-important distinction between 'Good on the whole' and 'Good as a whole'".
Lacan considered that "the sovereign good, if this confusing term must be retained, can be found again only at the level of the law", i.e. the symbolic order, offsetting Kant with De Sade to undercut nobler but one-dimensional notions of the Good. Earlier he had regretted the way the psychoanalyst must know, "Not only doesn't he have that Sovereign Good that is asked of him, but he also knows there isn't any".
Judgments on the highest good have generally fallen into four categories: