"CARL SAGAN SAID that if you want to make an apple pie from scratch, you must first invent the universe. When he says “from scratch,” he means from nothing. He means from a time before the world even existed. If you want to make an apple pie from nothing at all, you have to start with the Big Bang and expanding universes, neutrons, ions, atoms, black holes, suns, moons, ocean tides, the Milky Way, Earth, evolution, dinosaurs, extinction-level events, platypuses, Homo erectus, Cro-Magnon man, etc. You have to start at the beginning. You must invent fire. You need water and fertile soil and seeds. You need cows and people to milk them and more people to churn that milk into butter. You need wheat and sugar cane and apple trees. You need chemistry and biology. For a really good apple pie, you need the arts. For an apple pie that can last for generations, you need the printing press and the Industrial Revolution and maybe even a poem.
To make a thing as simple as an apple pie, you have to create the whole wide world."