Magic

Magic

Magic is a supernatural force discovered early in Poneren history. Magic and science are, in may ways, the antithesis of each other: while science is about studying and learning enough about a thing to be able to understand and change it, magic cannot work when it is observed too closely. The act of observing what is happening dampens the effect or even prevents it from occurring.
For magic to work, a sufficient understanding of the underlying systems of the world must be known for the magician to know what they want to change. However, as the magician cannot easily directly observe the change (but may observe it indirectly), it is difficult for magic to progress on its own. For true progress, scientific principles are generally employed.

Belief

At its core, then, magic is founded on "belief ". If there is enough expectation that something will happen, it will. The difficulties in this are that the "bigger" the change, the harder it is to believe. Or rather, people inherently believe that the world works in some way: say "the sun rises in the morning in the east". A lot of people believe that will happen, so to change it from happening, you might have to change a lot of people's minds. A "smaller" change, however, to get the same effect might be to believe that the earth's spin changes. If you were the only person that understood the earth's spin caused the sun to rise, then even though people believed the sun would rise in the east, without knowing why they wouldn't be able to stop your belief that the earth would rotate backward for a day.

Magic can do anything, but only if the magician believes it can

— A Treatise on the Limitations of Magic

This is why scientific principles are generally employed to progress magic -- by understanding the way the world works better, it's possible to find new ways of approaching problems. This is also why observation is an important component in magic -- it is very difficult to believe something that goes against our innate understanding of the universe.
It's also important to note that the belief that is seen may not actually be true, as long as the observer believes it is true. From the example of the sun rising in the east, people may believe it does that because the sun revolves around the world. However, the sun does not revolve around the world, nor does it need to, as the foundation of that belief is the direction the sun rises. Were the sun to revolve around the earth, it would go against other beliefs people have. It would cause the sun to be small and not produce enough light or warmth, or would cause gravity to work very differently.
Beliefs are tied together, so magic is not just about belief, but about believing in the right thing. And sometimes is about convincing others to also do so.
Magic that is seen while it occurs is difficult to believe, and easy to disbelieve. This means that seeing magic, even by the caster themselves, may dampen or nullify its effect. Seeing the effect of magic, however, does not do so. So magicians tend to work in secret when possible, and when not attempt to create magic whose root cause is disconnected from the effect they desire.

Source

The underlying source or reason for magic remains unknown.

Side Effects

All magic has side-effects.  These effects may not be required for magic to occur, but as it is widely believed to be a necessary outcome of magic, it always happens.
Side-effects supply a natural limitation to magical spells, requiring the magician to determine if the magic they desire is worth the potential and unknown effects (cost) of doing that magic.

Type

Metaphysical, Arcane