In a moment I knew what had happened. I had slept, and my fire had gone out, and the cold bitterness of death… — H.G. Wells

We are always getting away from the present moment. Our mental existences, which are immaterial and have no dimensions, are passing along the Time Dimension with a uniform velocity from the cradle to the grave. Just as we should travel down if we began our existence fifty miles above the earth's surface.

Very simple was my explanation, and plausible enough—as most wrong theories are!

Well, I do not mind telling you I have been at work upon this geometry of Four Dimensions for some time. Some of my results are curious. For instance, here is a portrait of a man at eight years old, another at fifteen, another at seventeen, another at twenty-three, and so on. All these are evidently sections, as it were, Three-Dimensional representations of his Four-Dimensioned being, which is a fixed and unalterable thing.