We shall court a similar fate if we develop cleverness without wisdom. I foresee rival projectiles landing simultaneously on the moon, each equipped with H-bombs and each successfully engaged in exterminating the other, But until we have set our own house in order, I think that we had better leave the moon in peace. As yet, our follies have been only terrestrial; it would seem a doubtful victory to make them cosmic.
Bertrand Russell, ‘The Expanding Mental Universe’
The big cities are finished! Even if they win this war, do you think the Traktionstadts will ever hunt again as real cities should? Of course not! They will cry, ‘Oh, we must not hunt Bremen; Bremen gave us covering fire when we bogged down on the Pripet Salient,’ or ‘It would be wrong to chase little Wagenhafn, after all that Wagenhafn did for us in the war.’ That is why they cannot defeat the Mossies, you see. They insist on helping each other, and as soon as you start helping others, or relying on others to help you, you give away your own freedom. They have forgotten the simple, beautiful act which should lie at the heart of our civilisation: a great city chasing and eating a lesser one. That is Municipal Darwinism. A perfect expression of the true nature of the world; that the fittest survive.
Philip Reeve, A Darkling Plain

Naga listened. He could hear the low voices of soldiers in the neighbouring trenches, the whisper of the breeze in his wolf-skin cloak, and faintly, far off, the song of a bird. Was it a nightingale? He wished he knew. He would have liked to tell his wife, when she came home from Africa, “We heard a nightingale singing, right out there on the front line!” But he had been too busy all his life with war to study such things as birds. If the peace held, he thought suddenly, he would learn all about them; birds, and trees, and flowers. He would walk with Oenone in the green meadows, and they would point out the birds and blossoms to one another, and he would be able to tell her what each was called.

"There!" he said, and his mechanical armour broke the stillness with a hiss and a clank as it swung him down off the fire-step. He clapped Colonel Yu on the shoulder with a steel hand like a Stalker’s gauntlet. "There! That’s what we have been fighting for, Yu Wei Shan. We didn’t go to war because we want to smash cities, but because we want to be able to hear the birds sing again. And if fifteen years of war won’t do it, we will have to try talking to the barbarians instead." He waved his arm, indicating the wastelands that lay beyond the wire; the immense shell-craters and concrete city-traps, the wrecked suburbs foundering in weeds, the million bones. "We were supposed to be making the world green again," he said, "and all we have been doing is turning it into mud."

Philip Reeve, A Darkling Plain