Chapter 5 of De mundo is markedly different from the preceding chapters examining technical details of astronomy, geography and meteorology. Chapter 5 takes an overall survey, presenting a view of the whole cosmos as a unified, well-ordered, magnificent and eternal whole – a true kosmos. Chapter 5 can be divided into three parts: the first introduces the Heraclitean principle of the harmony of opposites (396a33–b22), the second shows how this principle applies to the cosmos (396b23–397a5), and the third argues that the cosmos, built on this principle, is majestic and indestructible (397a5–b8). The detailed analysis of each part is accompanied with an attempt to position this text against the views of other Hellenistic philosophical schools, of the Epicureans and the Stoics as well as the Platonists. Having set forth the Aristotelian doctrine of the eternity of the cosmos, it was important for the author of De mundo to show that this does not undermine the beauty and teleological order of the world nor does it remove the need for God, thus setting the stage for Chapter 6.