Theories...

Ok, I have developed a theory. And, I'm really convinced that this is how it is... I'm proposing that the Wizarding World as described in the Harry Potter series is in fact the 4th dimension. It all adds up, what with floo powder(1) and platform 9 3/4(2) for inter-dimensional transportation. Their "magic" is possibly just their fourth dimensional abilities in layman's terms. Invisibility, levitation, walking through walls as examples.

Of course, being of a higher dimension, they can easily access our world and understand it how different it is from ours and how we "muggles"(3) (or three dimensional beings) are restricted in our world. Such as in Abbot's book entitled Flatland when a two dimensional Mr. Square is plucked from his two dimensional world by Lord Sphere of Spaceland. He is concluded insane and thrown in jail. If a person from our three dimensional world disclosed what they had seen in the Wizarding world of four dimensions, they would also be known as insane. Also, just as how our three dimensional world has more complex figures than Mr. Square's two dimensional world, the four dimensional world of Wizarding has more complex figures that can combine two or more familiar forms and even change between them, like the Animagi(4) and Metamorphmagi(5).

As stated in the books, it is a law to not use "magic" in front of muggles and only after a certain age may magic be used away from school. this, to me, sounds like  it could be perfectly explained by their four dimensions. Muggles would never be able to understand why these "wizards" were able to do things like levitate and go invisible without detailed explanations. Even the ghosts that are in the wizarding world have been speculated as being part of the fourth dimension. The Marauder's Map(6) and moving pictures also take us to a place of obvious higher dimension.


Of course, with our only look into this theory being JK Rowlings' books and speculation on them, we are quite limited, but if these are expanded upon intellectually, they are a viable opinion on what the fourth dimension actually could be.

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1. Floo powder is a glittery, silver powder used by witches and wizards to travel through the Floo Network. The Network connects most wizarding households and buildings. This powder was invented in the 13th century by Ignatia Wildsmith.
2. Platforn 9 and 3/4 is the platform from which the Hogwarts Express may be boarded on September the 1st.
3. Muggles are people who are born into non-magical families and are incapable of magic.
4. Animagi are witches or wizards who can morph themselves into a specific animal at will. It is a learned, rather than hereditary, skill, unlike those of a Metamorphmagus.
5. Metamorphmagi are witches or wizards with the ability to change his or her physical appearance at will, rather than requiring a potion or a spelllike the rest of the wizarding population. They are extremely rare
6. The Marauder's Map is a magical document that reveals all of Hogwarts School of Witchcraft and wizardry. Not only does it show every classroom, every hallway, every corner of the castle, but it also shows every inch of the grounds, as well as all the secret passages that are hidden within its walls.

**All definitions  provided by Harry Potter Wiki**