More Is Different: Nature’s Unruly Complexity
According to reductionism, every system, no matter how complex, can be understood in terms of the behavior of its basic constituents. The focus is on the bottom layer of the material chain: matter is made of molecules; molecules of atoms; atoms of electrons, protons, and neutrons; protons and neutrons of quarks; we don’t know if the buck stops here or not.
At the biological level, organisms are composed of organs; organs of cells; cells of organic macromolecules; those of many atoms, etc.
The more radical reductionists — lost, perhaps, in the fog of the eighteenth century’s giddy mechanization of reality — claim that all behaviors spring from a few fundamental physical laws: when we uncover these laws at the most basic level, we will be able to extrapolate to higher and higher levels of organizational complexity.