"Man’s cleverness is almost indefinite, and stretches like an elastic band, but human nature is like an iron ring. You can go round and round it, you can polish it highly, you can even flatten it a little on one side, whereby you will make it bulge out the other, but you will never, while the world endures and man is man, increase its total circumference. It is the one fixed unchangeable thing—fixed as the stars, more enduring than the mountains, as unalterable as the way of the Eternal. Human nature is God’s kaleidoscope, and the little bits of coloured glass which represent our passions, hopes, fears, joys, aspirations towards good and evil and what not, are turned in His mighty hand as surely and as certainly as it turns the stars, and continually fall into new patterns and combinations. But the composing elements remain the same, nor will there be one more bit of coloured glass nor one less for ever and ever."
Introduction, Allan Quartermen, H. Rider Haggard