Three weeks ago, a diamond specialist on SAfm explained how diamonds were formed, deep in the womb of the earth.

The specialist said that diamonds formed and gained their crystal brilliance under intense heat 200km beneath the earth’s surface, billions of years ago.

Upon hearing this, my mind began to grapple with fundamental questions of existence, questions we normally prefer to ignore.

If it is true that diamonds were formed 200km beneath the earth’s surface, how deep is the earth?

This important question had visited my mind a few years ago when I went on a tour of the Sudwala Caves in Mpumalanga. At some point, our tour guide said: “We are now 80m down.”

Looking around, it appeared to me that, at some point in antiquity, a geological vital force must have worked to hollow out a considerable portion of a mountain’s entrails, thereby leaving behind what we today call Sudwala Caves.

The mystery of the depth of the earth is connected to the enigma of time. In the eviscerated bowel called Sudwala Caves, you come across rock formations that are evidently still undergoing growth – one of which, it is said, is now 200million years old.

For an ephemeral mortal, such as man, 200million years are hard to fathom. Like the concept of depth, and indeed that of height, the human mind cannot grasp the concept of time when markers are removed.

To say something is 30 years old makes sense, but such a thing gives us no hint about the age of time itself.

The trouble is that time was there before the 30-year-old thing was born, and time will be there long after the said object has perished. What does it mean to say diamonds were formed billions of years ago? Exactly how old is time?

To ask how deep is the earth is to search for the boundaries of space. Conventional wisdom has taught us that everything has a beginning and end. Where, then, does space begin? And where does it end?

Here we are stuck. We are unable to trace the origins of time, and we cannot grasp the possibility of its finitude. We think we know what space is, but we cannot demarcate its frontiers.

To resolve our spatio-temporal problem, we resort to matter. We let ideas enter our heads to ourselves that nothing is older than time, and that nothing floats outside space.

I say “our” spatio-temporal problem because I count myself among those who believe that only we humans have the capacity for self-cognition.

I have come across no evidence to suggest that, other than the human mind, other sentient and non-sentient life forms are capable of entertaining the existential questions posed in this column.

We are unable to untie “our” spatio-temporal knot because of the very same natural laws we think we have discovered.

For example, we all believe that everything that exists has a cause.

Even as we are convinced of the inviolability of the law of causation, the human mind is incapable of retracing all the chains of causation that have produced the universe as we know it today.

Since we are so incapable, we have resorted to instrumentation, which is a device to extend the capabilities of the human body. Such is our power of abstraction.

When things are too infinitesimal to be perceived by our eyes, we trust what the microscope reveals to us. When we cannot climb to the high heavens, we send a satellite to spy for us, only to return without a glimpse of God and his holy angels.

We are dealing here with the fundamental problem of the human condition. Since we humans have an in-built mechanism called “consciousness” – the ability to rise and view nature as if we are hovering above it – we have become arrogant. We think we can explain everything.

There are creationists who have hatched out their theory of how the universe came about, and how it will all end. On the other hand, there are evolutionists who have propounded their own theory about how we have all sprung into our mega-habitat called the universe.

There are even Big Bang theorists who imagine the universe to be the product of a gigantic upheaval out of nowhere. Boooom… and everything was there!

All we lack is the simple wisdom to say: “I don’t know.”