4. The Fourth Dimension – A Line
Okay. The first three dimensions can be described with these words: “length, width, and depth”. What word can we assign to the fourth dimension? One answer would be, “duration”. If we think of ourselves as we were one minute ago, and then imagine ourselves as we are at this moment, the line we could draw from the “one-minute-ago version” to the “right now” version would be a line in the fourth dimension. If you were to see your body in the fourth dimension, you would be like a long undulating snake, with your embryonic self at one end and your deceased self at the other. But because we live from moment to moment in the third dimension, we are like our second dimensional Flatlanders. Just like that Flatlander who could only see two-dimensional cross-sections of objects from the dimension above, we as three-dimensional creatures can only see three-dimensional cross-sections of our fourth-dimensional self.