More Is Different
On the limitations of reductionism
“The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe”.
P.W.Anderson
What is the most real thing in the world? Is it the number pi? Is it the quantum fields merrily vibrating us into existence? Or is it the white and black on the screen on which you are reading this text?
In describing reality, the natural sciences go through a transition from the abstract universal to the idiosyncrasies of our lived reality: from quantum physics and relativity to molecules, cells, organisms, individuals, from solving Schrödinger’s equation in a Coulomb potential to the contingency of history and the uniqueness of its evolution.
The farther we move up the ladder, the more specific things get: from the mathematical simplicity of the gauge groups of the standard model, we get to the huge assortment of molecules in chemistry, whose expressivity, in turn, gives rise to the language of DNA, encoding a mind-boggling number of organisms, from bacteria to insects to reptiles to human beings. And when we think about humanity, there is an immense individual variety yet again: all the details of your existence are insanely specific, from our gender, nationality, and interests, to our eye color, hair color, personality…
