A dimension can be thought of as a degree of freedom. That is, a direction in which movement is possible. In a place with no dimension, everything exists as a point, with no possibility of motion in any direction. This mathematical abstraction is reminiscent of the physicist's conception of the state of the universe before the Big Bang.

In one dimension, motion is possible along a line either forwards or backwards. It is a state of duality, where the only aspirations available are to be closer or further. From this perspective, anything blocking the way is impassible and forms the boundary of the universe. This state can be illustrated by imagining the choices available to a trapeze artist suspended on a wire above the Grand Canyon.

In the second dimension, motion is only possible in a plane, much like driving a car in a vast parkinglot. Every object, regardless of whether it is a circle, square or a wavy line appears as a straight line from within a plane, since there is no notion of height, only of breadth. To see this, put your eyes level to a tabletop and look at the side of a coin, a paperclip, a CD, a knife. This perspective is playfully explored in FlatLand, a parabel written by Edwin Abbott in 1884 about a two dimensional being that is exposed to the third dimension.

"When my Grandson entered the room I carefully secured the door. Then, sitting down by his side and taking our mathematical tablets,—or, as you would call them, Lines—I told him we would resume the lesson of yesterday. I taught him once more how a Point by motion in One Dimension produces a Line, and how a straight Line in Two Dimensions produces a Square. After this, forcing a laugh, I said, 'And now, you scamp, you wanted to make believe that a Square may in the same way by motion "Upward, not Northward" produce another figure, a sort of extra square in Three Dimensions. Say that again, you young rascal.'"—Edwin Abbot, FlatLand

To reach the fourth dimension, we must make a similar leap: imagine extending a cube in a direction that is neither north, south, east west, up nor down, but is at the same time kindred to these directions. The object created by such motion, illustrated above, is called a hypercube.

Another way to approach a four-dimensional perspective is to consider how we can look right into inhabitants of Flatland and see all their pieces at once, inside and out. Then, imagine how your body would look to a four-dimensional being: visible inside and out, clothing, skin and organs all at once. Now consider that this object, your whole body, is just a part of the surface of a four dimensional object.

Our experience of time is often considered to be evidence of the fourth dimension. Perhaps the future is a "direction" we could move a cube in to get a hypercube. To see it, however, we would have to be able to view all of time at once.

A provocative work on considerations of the fourth dimension, Tertium Organum was written in the 1920's by a Russian mathematician and mystic, P.D. Ouspensky. Explored is the idea that we experience the fourth-dimension all the time imperfectly with our limited organs of perception as love, art, beauty and so forth.

"If we touch the surface of the table with our five fingertips of one hand, there will be then on the surface of the table only five circles, and on this surface it is impossible to have any idea either of the hand or of the man to whom the hand belongs. There will be five separate circles on the table's surface. How from these is it possible to picture a man, with all the richness of his physical and psychological life? It is impossible. Our relation to the four-dimensional world may be exactly the same as the relationship between that consciousness which sees the five circles on the table and the man. We see only 'fingertips'; that is why the fourth dimension is incomprehensible for us."—P.D. Ouspensky, Tertium Organum

The idea that many apparent individuals are infact "fingers" of a greater being can be found actualized right here in the third-dimension in plants that have an extensive, but hidden root system, such as aspens and mushrooms. To consider if there is a four-dimensional entity of whom you are but an organ or hair or finger may seem foreign and unknowable, but for some it is just the beginning of a larger conception of being itself.

"It is necessary to go farther, and to recognize a very wide extension of the idea of Higher Space, which is by no means exhausted when we have reached the conception of Space of Four Dimensions... When we have recognized the existence of Space of Four Dimensions there is no greater strain called for in the recognition of the existence of Space of Five Dimensions, and so on up to Space of an infinite number of Dimensions.

"...And though it is impossible even to begin to imagine what the appearance of a material object in our Space may be to an observer in a much Higher Space, still it is evident that to him is presented a still more infinitely perfect view of its constituents than to an observer in any Lower region of Space. While to an eye in the Highest Space of all, an infinitely perfect revealing of the most hidden and secret things is of necessity presented.

"This emphasizes very strongly what has been said about the Omniscience of God. For he, dwelling in the Highest Space of all, not only has this perfect view of all the constituents of our being, but also is most infinitely near to every point and particle of our whole constitution. So that in the most strictly physical sense it is true that in Him we live and move and have our being."—Arthur Willink, The World of the Unseen (1893)