Posted: Mon, 10/28/2013 - 5:35 pm EDT
The classic example is thinking about a car. Cars are made of nuts, bolts, metal rods, big metal blocks, rubber or paper gaskets, plastic containers
for fluids, rivets, wires, and so on. (Each piece of metal is further made of atoms, which are made of electrons, protons, and neutrons, which are made
of quarks, and so on down.) But if you're trying to repair a car, you don't think in those terms; if you did, you'd never find where the problem is.
Instead you think about the engine, the alternator, the fuel injectors, the brakes, the transmission, and so on.