For many medieval thinkers, Plato's thinking provided the necessary philosophical groundwork for belief in an afterlife. For the most part, the medieval theologian/philosophers welded Platonism to Christianity so firmly that criticism of the synthesis was nearly tantamount to heresy. This dogmatism was reflected clearly in Bonaventure (1221–1274), a Franciscan and Augustinian thinker who rejected the influx of Aristotelian ideas in his time because they seemed to deny the immortality of the soul.
In the same way, the wise man does not consider Fortune to be a goddess, as some men esteem her to be, for the wise man knows that nothing is done at random by a god. Nor does he consider that such randomness as may exist renders all events of life impossible to predict. Likewise, he does not believe that the gods give chance events to men so as to make them live happily. The wise man understands that while chance may lead to great good, it may also lead to great evil, and he therefore thinks it to be better to be unsuccessful when acting in accord with reason than to be successful by chance when acting as a fool.
Happiness is the greatest good, says Epicurus following Aristotle . And happiness, is the maximization of pleasure. Whether all pleasures are good sources, Epicurus distinguishes the dynamic pleasures (eating) and static pleasures (satiety), which are recommended by the pleasures Epicurus. Pleasure is a state of static equilibrium between the satisfaction of desire and the birth of new desires, frustrations and pain. Similarly, Epicurus distinguishes the physical pleasures of psychological pleasures. This relates to physical pleasures, which must be reduced to a minimum satisfaction. The future, and its corollary fear of the future is what keeps the soul to reach equilibrium at ataraxia.