The European Medieval world was hierarchical in structure: conceptually, the world was a combination of Aristotelian physics and Christian ideas in a Ptolemaic universe.

According to Aristotle the world was composed of a hierarchy of four elements: air, fire, water and earth. Each element sought to fulfill its nature, that is, its natural place in the hierarchy. (This is Aristotle's 'Final Cause': as the acorn is the cause of the oak tree).

Earth seeks to be on the surface of, or inside of, the planet (what we call gravity).

Water seeks to flow on top of the earth.

Fire seeks to rise up.

Air floats at the top of the hierarchy.

Also in accord with Aristotle, the planet earth was flat.

So, the flat earth was the center or bottom of the hierarchy. Next in the hierarchy came water, then fire and then air. Above the air, the hierarchy was called the firmament. This was where the heavenly bodies, all the stars and planets that could be seen, were fixed in place (what we today call space). Then in the hierarchy came heaven, where the angels and ultimately, God, dwelled:

Medieval Hierarchy

God
Angels
Heavens
Air
Fire
Water
Earth
Humans
Animals
Plants
Minerals

At this time, circles were considered to be the perfect form and circular motion was considered to be perfect movement. Thus, the orbits of the planets and stars were thought to be circular.

However, there was a problem. When observed closely over time, the stars and planets did not appear to move in perfect circles.

Over the years, as more and more anomalies were observed (differences from what would be perfect circular motion), astronomers devised a method of explaining where the stars would appear that accounted for the facts (observations) and maintained the principle of perfect circular motion. This method relied on what were called epicycles. The idea was that a particular star would travel (rotate, really, as in a planetarium) in small circles along the path of a larger circle.

In this way, the fluctuation of a star (that is, when it would stray from the perfect circular path) was explained by a smaller circle rotating around the larger circular path. Whenever a star did something that did not fit a perfect circular path, a new epicycle would be added to explain the observed location of the star.

The idea was to maintain the Medieval Catholic Church view of the world and observed facts would have to be made to fit into this explanation (which had to be correct). [This is an example of an absolute - God's word - changing the interpretation of the facts]

It was important to the Medieval Catholic Church that the heavens were believed to be perfect. That was because the heavens were where God and His Angels dwelled. God and His Angels were perfect, so their home, logically, would be perfect as well. The earth itself was imperfect and was inhabited by imperfect creatures (human beings). Only in the heavens was perfection to be found. The planets were thought to be perfectly circular and the surfaces of the planets were thought to be perfectly smooth.

Thus, the philosophers of the Medieval Catholic Church built upon the foundation of Aristotelian and Ptolemaic thought to develop a worldview that explained everything in accordance with the top down, hierarchical structure of Medieval Catholicism.

In Medieval Europe, the social, economic and political systems were hierarchical.

In Medieval society, everyone had their place in the world; everyone knew what they were expected to do; everyone knew their job, role, position, and responsibilities. Everyone's place in society was based on their family's status, wealth and power. There were nobles and commoners and whether you were one or the other depended on your heritage (bloodline). Skills were passed on from one generation to the next, so that if your father were a blacksmith, you would likely be a smith as well, as your family name was likely Smith.

Historians have named the economic system 'manorial': people lived on large estates (called manors by historians) owned by a nobleman (a member of the nobility by birth; a knight). The common people were either free or were serfs (who belonged to the land and were subject to the landowner/lord). The manor was relatively self-sufficient. There were fields for farming, a mill, a smith, and walls surrounding the manor for protection. The people provided manual labor and skills to produce the food, clothing and other necessities of life. The lord taxed the people, taking a share of their crops for use of the land, the water, the game (wild animals), and any other possessions belonging to the manor.

Land and titles (wealth) were passed on from one generation to the next through the oldest male child. This system is called primogeniture. The second son (and any other younger sons), who would not inherit the title, land and wealth of the father, would go into Medieval Catholic Church service. This was not an act of charity. The younger sons would serve the interests of the family or clan from within the Medieval Catholic Church by gathering information, making decisions and suggesting policies and actions that would be of benefit. Noble women would marry those chosen for them, usually for such practical ends as uniting smaller parcels of land to form a larger estate for future generations. Over many generations, large landholdings indeed were accumulated in this manner.

The political system employed to exercise power in this setting has been called feudalism by historians. The lord of the manor was in charge of (responsible for) justice (making the law, enforcing the law) and protection (from thieves, robbers, villains and other lords and nobles). The lord of the manor, usually a knight (a soldier) often received his title from another nobleman, to whom he owed allegiance (fealty). This required that the knight comply when the nobleman needed the knight's assistance to fight another nobleman. Frequently, the knight would have to pay the nobleman an annual tax (either in bullion or in kind) as well. After many years, a complex, patchwork system of allegiances existed.