Arthur C. Clarke says it perfectly;
Magic is just science that we don't understand yet.
This is a theme that flows throughout the series but is not as we understand it to be. The humans see magic as just that, but the Orkarian's know and use magic all the time. It doesn't exist as something that requires a wand or other object necessarily, but it is the ability to wield and manipulate the very atoms of the world.
There are four elements, earth, fire, water, and air and it is from these that the relevant atoms are controlled by the individual. After humans crash land on the planet, they are met by the welcoming and very science-focused Orkarian people who introduce them to the elements.
After over a thousand years, the humans don't understand this and have come from a planet that already has religion, they name these elements (which are considered blasphemous) as gods.
Creating a structure that looks like this:
Earth - Diva Ad Nu (name of god) - Vanadium (atom) - Green (colour representation) - Burial
Fire - Arc Don (name of god) - Carbon (atom) - Black (colour representation) - Cremation
Aer - Exenogy (name of god) - Oxygen (atom) - White (colour representation) - Exploding Lantern
Water - Dyer Gon (name of god) - Hydrogen (atom) - Blue (colour representation) - Sea Burial
So whilst the Orkarian people try their hardest to teach the humans how to utilize these, the humans become gorged on power and wage war against the peaceful Orkarian natives, sending the world into a crisis for the first time in two eras. The Orkarian people withdrew from the island, which the humans named Erde, after their homeworld, only to be observed from afar by the natives, and kept on the island by dangerous storms which prevent them from sailing. Contained on the island, the humans create an order of monks which is to retain all knowledge of the gods and their true power but are forbidden to share. Over time, knowledge from books became a myth as they were confiscated by those in power to stop the pursuit of power.
As such, we reach the present day, where Rey is only just beginning to learn about the true history of the humans...however, what she does learn is a single drop and to fully understand what happened to her people, she must find the Sage, for only they have the knowledge she seeks. But, the Sage is unknown and lost in time, like all that came before.