One General Law

…it may not be a logical deduction, but to my imagination it is far more satisfactory to look at such instincts as the young cuckoo ejecting its foster-brothers,—ants making slaves,—the larvæ of ichneumonidæ feeding within the live bodies of caterpillars,—not as specially endowed or created instincts, but as small consequences of one general law, leading to the advancement of all organic beings, namely, multiply, vary, let the strongest live and the weakest die.

Darwin closes his chapter on instinct by gathering the cruelest habits he knows, the cuckoo, the slave-making ant and the wasp larva inside a living caterpillar, and refusing to call them designed.

Source: Charles Darwin, On the Origin of Species, 1st ed. (John Murray, 1859), ch. VII "Instinct," closing paragraph. Text: Project Gutenberg. Public domain in the US. Pairs with: Major Arcana: Judgement or Wheel of Fortune A note from 2026: "The advancement of all organic beings" is Victorian faith in progress. Modern evolution has no built-in direction, and selection is about reproductive success more than strength.

Public domain in the United States.