A traditional synopsis of the Theogony might go as follows. The gods Khaos, Gaia, and Eros "come to be". Then Khaos gives birth to Nyx and Erebos, who in turn give birth to Hemera and Aether. Gaia gives birth to Ouranos and Pontus. Ouranos and Gaia beget the twelve titans, as well as the Cyclopes and the Hundred-Handed Giants. Ouranos entraps the latter two within Gaia. Gaia is enraged, and has Khronos, the youngest Titan, castrate his father (thereby separating earth from sky, after which he becomes master of the world. The Titans have their own children. To forestall a prophecy of his overthrow from coming true, Khronos devours each of his children, except Zeus, who Khronos's sister-wife saves by feeding her husband a rock in swaddling clothes. When Zeus comes to maturity, he forces Khronos to vomit out his siblings. Zeus and his siblings then go to war with the Titans. With the aid of the Cyclopes and Hundred-handers, Zeus overthrows the Titans and entraps them in the underworld realm of Tartarus. Zeus later has a final duel with Typhoes.
In Hesiod's Theogony, as in much creation mythology, inanimate objects (like earth), forces (like love), and phenomena (like night) are presented to a large degree as acting beings: they are anthropomorphized. Thus, the story Hesiod tells might seem to be dismissed as a superhuman soap opera: an interpersonal saga, in which the characters happen to have outlandish powers. However, the Theogony can also be viewed in a vastly different way.
The great philosopher Aristotle, who wrote some 400 years after Hesiod wrote his Theogony, made a sharp distinction between two classes of thinkers: theologi and physici. Thetheologi impute the causes of phenomena to personal, mysterious gods, the knowledge of whom is only accessible through divine revelation. In stark contrast, the physici look to impersonal, discernible forces which can only be detected through careful observation and reasoning. The ranks of the theologi were supposed to be filled with poets, priests and prophets. The ranks of physici were populated by proper philosophers. However Aristotle made a possible exception for Hesiod. He surmised that the great poet showed his truephysicoi colors in his cosmological formulations.
When Greek myths are translated into English, the names of the gods are left in a transliterated version of the original Greek. Thus it can be easy to miss the fact that many (if not all) of Hesiod's gods in the Theogony are anthropomorphized representations of observable objects, forces, and phenomena. For example, Gaia is not simply the name of "the goddess of the Earth". "Gaia" literally means "earth" in Greek (it is the origin of our "geo-" prefixes in our words "geology" and "geography"), and Gaia was thought of as the earth itself. Thus, if you ignore the proper noun treatment Hesiod gives to his objects, forces, and phenomena, what at first might seem like a fairy tale of love and strife between gods begetting children and blood will seem more like an impersonal account of attraction and repulsion between natural objects begetting generation and dissolution.
So, a "naturalistic" telling of the Theogony might be as follows. First there was invisible air (Khaos). Then earth (Gaia) and attractive/generative force (Eros) came to be. Then out of air came a dark gas (Erebos) charged with its own motive energy (Nyx). Out of that came a bright gas (Aether) charged with its own motive energy (Hemera). A starry firmament (Ouranos) springs up out of the Earth, as well as salt water (Pontus). The firmament holds the earth down, and matter from the former is compelled by the attractive force to come down upon the latter. This process generates twelve entities, including: time (Khronos) and its motive force (Rhea), fresh water (Okeanos) and its motive force (Tethys), inquiry (Koios), intelligence (Phoebe), mortality (Iapteus), natural order (Themis), memory (Mnesomyne), and sight (Theia). The same process later generated storms (Cyclopes being the lightning and thunder and Hecatonshires being the winds), which became entrapped within the earth. Time itself brought a halt to this process. The twelve entities, as well as the motive energy of the dark gas (Nyx) then engendered further entities. Some were abstract forms which would later be actualized in human affairs, such as strife, rumor, etc. Some were material beings such as rivers and mountains.
Taken thus, Hesiod's Theogony exemplifies many important strands in the history of thought regarding "natural history". In the Theogony, there is no one special creator, and no single instance of creation. Instead there is a gradual process of generation and change.
Of course for all his systematic and rational presentation, Hesiod still had his "Time" entity literally castrate his "Sky" entity with a flint sickle. His audience expected the interpersonal saga of epic poetry, and this necessitated that his cosmic powers have distinctly human characteristics.
Next in this series: History in the Theogony.