All the great breakthroughs in science are, at their core, compression. They take a complex mess of observations and say, "it's all just this simple rule". Symbolic compression, specifically. Because the rule is always symbolic -- usually expressed as mathematical equations. If it isn't symbolic, you haven't really explained the thing. You can observe it but you can't understand it.

The universe is a beautifully consistent system of rules. Intelligence is the efficiency with which you can go from the output of these rules (what you can observe) back to the rules themselves.