Beatific vision

In Roman Catholic theology, the beatific vision is the eternal and direct perception of God enjoyed by those who are in Heaven, imparting supreme happiness or blessedness.While humans' understanding of God while alive is indirect (mediated), the beatific vision is direct (immediate).
Thomas Aquinas defined the beatific vision as the ultimate end of human existence after physical death.Aquinas's formulation of beholding God in Heaven parallels Plato's description of one beholding the Good in the world of knowledge.

The beatific vision was featured in a controversy when Pope John XXII denied that the saved experienced it before Judgment Day.

Roman Catholic tradition

Saint Cyprian wrote of the saved seeing God in the Kingdom of Heaven.

"How great will your glory and happiness be, to be allowed to see God, to be honored with sharing the joy of salvation and eternal light with Christ your Lord and God... to delight in the joy of immortality in the Kingdom of Heaven with the righteous and God's friends" ~ St. Cyprian

More specifically, Catholic Encyclopedia defines the beatific vision:

The immediate knowledge of God which the angelic spirits and the souls of the just enjoy in Heaven. It is called "vision" to distinguish it from the mediate knowledge of God which the human mind may attain in the present life. And since in beholding God face to face the created intelligence finds perfect happiness, the vision is termed "beatific".

In Catholic theology, the intercession of saints is valid because those who have died in the faith are with God in Heaven and enjoy the Beatific Vision, i.e., unmediated access to God's presence.

Platonism

In the philosophy of Plato, the beatific vision is the vision of the
Good. In Plato's Allegory of the cave, which appears in the Republic Book 7 (514a - 520a), he writes (speaking, as he consistently does through all but one of his extant works, through the character of Socrates):

"My opinion is that in the world of knowledge the idea of good (the Good) appears last of all, and is seen only with an effort; and, when seen, is also inferred to be the universal author of all things beautiful and right, parent of light and of the lord of light in this visible world, and the immediate source of reason and truth in the intellectual." (517b,c)

Thus, for Plato, the Good appears to correspond to God in Christian theology.
St. Augustine expressed views similar to Plato's on this subject, and was familiar with Plato's ideas, either directly or via the writings of
neoplatonists.

History of the beatific vision

In the 13th-Century, the philosopher-theologian Thomas Aquinas described the ultimate end of a human life as consisting in the intellectual Beatific Vision of God's essence after death. [http://www.newadvent.org/summa/200308.htm see "Summa Theologiae"]

According to Aquinas, the Beatific Vision surpasses both faith and reason. Rational knowledge does not fully satisfy humankind's innate desire to know God, since reason is primarily concerned with sensible objects, and thus can only infer its conclusions about God indirectly. [http://www.newadvent.org/summa/101212.htm "Summa Theologiae"]

The theological virtue of faith, too, is incomplete, since Aquinas thinks that it always implies some imperfection in the understanding. The believer does not wish to remain merely on the level of faith, but to understand what is believed. [http://www2.nd.edu/Departments//Maritain/etext/gc3_40.htm "Summa Contra Gentiles"]

Thus only the fullness of the Beatific Vision satisfies this fundamental desire of the human soul to know God. Quoting St Paul, Aquinas notes "We see now in a glass darkly, but then face to face" (i Cor. 13:12). The Beatific Vision is the final reward for those saints elect by God to partake in and "enjoy the same happiness wherewith God is happy, seeing Him in the way which He sees Himself" in the next life. [http://www2.nd.edu/Departments//Maritain/etext/gc3_51.htm "Summa Contra Gentiles"]

Pope John XXII (1316 - 1334) caused a controversy involving the Beatific Vision.He said, not as Pope but as a private theologian, that the saved do not attain the Beatific Vision until Judgment Day. The general understanding at the time was that the saved attained Heaven after being purified and before Judgment Day. He never proclaimed his belief as doctrine (see ex cathedra). The Sacred College of Cardinals held a consistory on the problem in January 1334, and Pope John backed away from his novel views to the more standard understanding.His successor, Pope Benedict XII, declared it doctrine that the saved attain Heaven before Judgment Day.