Chapter IV: The World of Four Dimensions Summary and Analysis

Time is a Fourth Dimension

The concept of a fourth dimension is difficult if not impossible for humans to understand. How can a four-dimensional object become part of our world? We are able to place a three-dimensional object into a two-dimensional plane by drawing a picture of it on a piece of paper. This process is is referred to as geometrical projection. By using geometrical projection, we can squeeze a four-dimensional object into our three-dimensional world without part of it sticking out. We can project a three-dimensional cube onto a plane and find that it assumes a form with two squares, one inside the other. The projection of a four-dimensional supercube would produce a form consisting of a cube within a cube connected by the vertices.

The plane projection...