I have had a breakthrough in my understanding of the Imagination - which came to me when reading a passage from Jeremy Naydler's essay Ancient Egypt and modern esotericism - from the book The Future of the Ancient World (2009). I now feel I understand the function of Imagination.
The cosmic being who presided over Ra's diurnal voyage across the sky was the heavenly goddess Nut. It was she who gave birth to Ra each morning, and who received him into herself again in the evening.
Each evening, when the sun god Ra entered her interior realm, he entered the secret and wholly invisible world that the Egyptians called the Dwat [usually spelled Duat]. The Dwat was conceived as being on the other side of the stars that we see when we look up at night. The stars were imagined as being on the flesh of the goddess Nut, and the Dwat was in some sense behind or within the world of which the stars demarcated the outermost boundary.
All creatures were believed to return to the Dwat at the end of their lives, and wer born from it again, just as the sun God was born from the Dwat each morning.
Knowledge of the interior world of the Dwat was considered by the Egyptians to be the most important, most profound knowledge, for people living on Earth to acquire. The Dwat was not only the realm of the dead, but the realm of the gods and spirits, and furthermore the realm from which all living things emerge. All life issues from the Dwat.
To know this mysterious interior world was to become truly wise, because then one would know both sides of existence - the invisible along with the visible.
The Egyptians lived with an awareness of a dimension of reality that is best described by the term 'Imaginal'. It is a nonphysical yet objective reality that we become aware of through the human faculty of Imagination.
In other words, the reason that Men posses the faculty of Imagination, why it is built-into us, is so that we may know imperceptible reality.
That is what Imagination is for.
So, Man knows perceptible reality via his perception - the senses of vision, hearing, smell touch and taste - that is why we are born with eyes, ears, noses, tongues and skin receptors; and Man knows the imperceptible reality via the faculty of Imagination: that is why we are born with the faculty of Imagination.
Of course the Imagination can err - but so can the senses. But to deny the reality of Imagination as a source of knowledge - of real, objective, necessary knowledge - is akin to denying the reality of everything we get from our senses.
Yet, of course, that is what mainstream modern public discourse does assume - that Imagination is a mixture of hallucinations and refers to nothing real. We are in the position of someone who assumes that everything he sees, hears, tastes, touches and feels is a hallucination.
Which neatly explains the strange psychoticism of our Imagination-denying society - its gross and yet systematically un-noticed pathology.
It is is a difference which goes far to explain why Ancient Egypt was so adaptive as to persist for 3,000 years, why The West will not reach 300.