I am intrigued by the notion that there is a limit to what we as humans can perceive about the universe.

Consider our dimensional space. The first dimension can be thought of as a line with no other features. The second dimension is perpendicular to the first and it also can be described as a single line, but by combining the first and second dimensions we get a plane, any point on which can be described with 2 numbers (x,y). By adding a third dimension at right angles to the first two, and combining all three, we get a cube-shaped space, in which the location of any point can be described with three numbers (x,y,z). We conceive of the universe as having three spatial dimensions and one time dimension. We can feel in three dimensions, but we only see in two dimensions and our brain deduces the third dimension visually by using other clues such as relative size, motion, juxtaposition of three dimensional objects etc. If we could actually see in three dimensions we would be able to see around and through objects, just as we can feel around and through objects.

Suppose the universe is actually four dimensional but we are only living in, or at least only aware of, three of those dimensions. There is no mathematical reason why there cannot be a fourth spatial dimension and the location of any point within that space would be defined as (x,y,z,a). We at present have no way to see or feel along that fourth dimension. To understand the idea, imagine we lived in a two-dimensional space – a plane. The plane is the limit of our perception, up down and sideways, but not depth. Now imagine a small three-dimensional object astride our plane of existence and perception. We can see one slice of the object. If it moves along the third dimension, we will see new slices of the object until it no longer crosses our plane of existence and disappears from view. It might remain quite close to us but just off our two-dimensional plane and we would never know it was there.

Now let’s suppose we actually live in a three-dimensional space (as opposed to a two-dimensional plane) but that a fourth dimension exists. Now imagine a small four-dimensional object crosses our cube-shaped space of perception and existence. We can perceive only the three-dimensional part of the four-dimensional object. If it moves along the fourth dimension, we will see new three-dimensional parts of the object until it no longer crosses our cube-shaped space of existence and disappears from view. It might remain quite close to us but just off our three-dimensional cube-shaped space and we would never know it was there. Now we can also play tricks if we knew there was a two-dimensional organism. We could choose to wink in and out of the perception of that two-dimensional organism just by shifting position along the third dimension (the depth dimension) perpendicular to the plane until none of our three-dimensional parts cross the plane.

Let’s further suppose that our universe really does have four spatial dimensions. What if two independent origins of life began on our earth – one a three-dimensional chemical process and the other a four-dimensional chemical process? We, as three-dimensional organisms will only interact with the four-dimensional organisms when they are in a position on the fourth dimension that crosses our cube of existence. They might look quite ordinary in three dimensions, or they might be quite different. But whatever their appearance, they would (or could) wink in and out of our perception as they moved along their fourth dimension. What might their evolution have been like? Would it have been a parallel evolution to our own – or perhaps not quite the same, but close, except that they have this extra dimension to their actual shape?

Speculative science (fiction?) might allow us to imagine that there are four-dimensional micro-organisms, equally wild ancient types like 4-D trilobites and huge 4-D trap-jaw fish. Perhaps as 4-D evolution proceeded many of the so-called mythical beasts were not so mythical. The bible for example mentions the Behemoth, the unicorn (nine times), the cockatrice (a rooster-headed dragon), Lilith (a female demon), and satyrs (half-man, half-goat creatures). Abaddon’s locusts resemble war horses, have the stinging tails of scorpions, the faces of men, long hair like a woman’s, and wear crowns of gold and armored breastplates. Their scorpion’s tails are used to sting their victims, an experience that’s apparently so painful that ‘men shall seek death, and shall not find it.’ The 200 million horsemen whose horses have the heads of lions, tails like serpents, and spit smoke, fire, and brimstone out of their mouths, are eventually responsible for the deaths of a third of all mankind. There are lots of references to dragons and angels, and of course, the ultimate Leviathan. Almost all of these beasts and angels are immune to human weapons (slipping in and out of the fourth dimension?). Similar stories abound in almost all legends from around the world. Many such beliefs (real or imagined) are current today: fairies, sprites, pixies, elves, imps, brownies, pucks, and leprechauns. Are they actually 4-D sprites? And what about 4-D aliens who can wink in and out of existence, even taking our three-dimensional bodies with them for experimentation before returning them alive to our three-dimensional world!

There are times when I think I must set my pen or my glasses down on a spot that moves in and out of the fourth dimension, I’m sure it can’t be that I am forgetful.