What I mean is, I have read how many equations that model physical phenomena often aren't directly solvable. Instead they are approached by successive approximations. And we get answers that are close enough. My question is, if a physical phenomenon seems to follow a mathematical pattern, why is it we can only approximate the math, instead of solve an exact set of equations. Obviously the phenomenon is not doing successive approximations to approach the actual state it ends up in, it just does it. If a physical system can "do" something, why is there not an exact equation to describe it? I hope the question makes sense.