When high level behavior that can be described by simple equations emerges from low level laws, we call it physics. When it doesn't, we call it chemistry, biol

When high level behavior that can be described by simple equations emerges from low level laws, we call it physics. When it doesn't, we call it chemistry, biology, geology, etc. (EDIT: how could I forget econoimics :-)) There is only one thing which is more unreasonable than the unreasonable effectiveness of mathematics in physics, and this is the unreasonable ineffectiveness of mathematics in biology. — Israel Gelfand