The idea of purgatory, not as a place definitely located like Dante's Mount of Purgatory, but rather as a period of punishment and probation, is expressed in these lines from _The Parlement of Foules_ (78-84): "'But brekers of the lawe, soth to seyne, And lecherous folk, after that they be dede, Shul alwey whirle aboute therthe in peyne, Til many a world be passed, out of drede, And than, for-yeven alle hir wikked dede, Than shul they come unto that blisful place, To which to comen god thee sende his grace!'" Chaucer uses the idea of paradise for poetical purposes quite as often as that of purgatory. He expresses the highest degree of earthly beauty or joy by comparing it with paradise. Criseyde's face is said to be like the image of paradise.[32] Again, in extolling the married life, the poet says that its virtues are such "'That in this world it is a paradys.'"[33] And later in the same tale, woman is spoken of as "mannes help and his confort, His paradys terrestre and his disport."[34] When Aeneas reaches Carthage he "is come to Paradys Out of the swolow of helle, and thus in Ioye Remembreth him of his estat in Troye."[35] Chaucer mentions paradise several times in its literal sense as the abode of Adam and Eve before their fall. In the _Monkes Tale_ we are told that Adam held sway over all paradise excepting one tree.[36] Again, the pardoner speaks of the expulsion of Adam and Eve from paradise: "Adam our fader, and his wyf also, Fro Paradys to labour and to wo Were driven for that vyce, it is no drede; For whyl that Adam fasted, as I rede, He was in Paradys; and whan that he Eet of the fruyt defended on the tree, Anon he was out-cast to we and peyne."[37] 5. _The Four Elements._ The idea of four elements[38] has its origin in the attempts of the early Greek cosmologists to discover the ultimate principle of reality in the universe. Thales reached the conclusion that this principle was water, Anaximines, that it was air, and Heracleitus, fire, while Parmenides supposed two elements, fire or light, subtle and rarefied, and earth or night, dense and heavy. Empedocles of Agrigentum (about 450 B. C.) assumed as primary elements all four--fire, air, water, and earth--of which each of his predecessors had assumed only one or two. To explain the manifold phenomena of nature he supposed them to be produced by combinations of the elements in different proportions through the attractive and repulsive forces of 'love' and 'discord.' This arbitrary assumption of four elements, first made by Empedocles, persisted in the popular imagination throughout the Middle Ages and is, like other cosmological ideas of antiquity, sometimes reflected in the poetry of the time.