Cybermen: A Dark Mirror to Humanity — The Tenth Planet →
Philip Sandifer, in his sublime essay on “The Tenth Planet”:
Certainly it’s worth noting that Pedler’s original conception of the Cybermen was as a race of “star monks.” Here it is instructive to look at the origin of the Cybermen, as completely and utterly screwed up as it may be. Mondas and Earth are twin planets - the one an inversion of the other. The Cybermen tell us that they and Mondas “drifted away on a journey,” making a sweeping arm motion as they do, and that they went to the edge of space, then returned. In the course of that journey, their bodies wore out and they steadily replaced themselves with spare parts, removing human weaknesses in the process.
The Cybermen, in other words, are an alternative version of humanity - the dark mirror of humanity, who went on a quest for spiritual enlightenment and succeeded at terrible cost.