The cosmological revolution of the seventeenth century saw the establishment of physics and astronomy as autonomous spheres. The Ptolemaic universe was a hierarchy of dignity – sun and stars above, lowly earth at the bottom – supported by a hierarchy of disciplines that set theology and metaphysics at the apex of intellectual life. The advancing belief in heliocentrism that undid the first was paralleled by challenges to the second, starting with the humanist celebration of rhetoric and moral philosophy and carried further by Copernicus’s exaltation of astronomy, hitherto assigned the lowly place of a mere computational aid, as a source of truth. The authority of the Church was often restricted by political and cultural divisions, so that many heretical ideas could not be stamped out, and Galileo long found support from Jesuits and even the pope. As he lost it, he sought backing in a wider audience, publishing his writings in Italian rather than Latin, and in a popular style. Newton and his followers would similarly seek to substitute horizontal connections for the vertical ones around which intellectual life had long been organized, demonstrating elements of their theories to popular audiences and explicitly describing the kind of science they favored as “public.”

On a cultural level, the Italian Renaissance lifted Europe into a new era of humanism that glorified humanity and shifted attention to the present needs and desires of people. Erasmus translated this humanistic attitude into scholarly pursuits that revealed the frailties and needs of the human authors of Scripture. All of these forces eroded the authority of the Church, leading to dramatic confrontation, both from inside and outside the Church. The Protestant Reformation took advantage of the rift between Christian monarchs and the papacy, successfully fragmenting the unity of Western Christendom. However, it was Copernicus who used the strategy and tools of reasoned arguments to arrive at his heliocentric theory of planetary motion. This bold assertion successfully demonstrated a truth arrived at through reason that differed from the conclusion supported by the authority of the Church. As a result, reason triumphed over faith, and the age of science began. While psychology remained obscured within philosophy and religion during this time, the enduring questions still perplexed scholars and were about to be addressed directly over two centuries of philosophical inquiries prior to psychology’s formal definition as a distinct science.

The last part of Chapter 2 and the first part of Chapter 3 of De mundo (392a31–393a8) describe the cosmic layers further below the sphere of the moon, leading down to the very centre of the universe. This section provides a brief overview of the sublunary layers of the four elements (fire, air, water and earth), some of which will be discussed in more detail later in the text. The two main theses that constitute the reasoning behind this section are (i) continuity throughout the entire cosmos and (ii) the great variety of phenomena and processes within the sublunary domain. The layers are organised from the most active one at the top down to the most passive one at the centre of the universe. The continuity among the layers is demonstrated on each and every level. There is, however, no suggestion that each lower, less active substance gains all its characteristics from the more active substance above. For our author’s purpose it is sufficient to demonstrate that there is some relation, some communication among the layers which can later be used by the divine dunamis permeating the entire cosmos. The final part of the present section concerns the claim that the continents are large islands surrounded by an ocean.