Knowing physics is knowing practically any step of nature well before it makes it. Knowing Newtonian mechanics we can predict when Moon will eclipse Sun thousands of years ahead, predict what will star position look like in 10, 50 100 thousand years from now, etc. Knowing relativity we can for sure predict that there will be magnetic field of certain intensity if electron will start moving with certain velocity and well before electron actually moves, we can predict bending of light before it traverse certain way, we can predict zillions of other things just knowing that nature obeys simple mathematical rules called symmetries or natural laws.

By well knowing the math which results in natural laws we can built good shelters, transportation and communication machines, entertainment machines like TV, rock band electronics, build computers -math machines and artificial intelligence software(brains), cure complex bacterial, viral and genetic deseases, we can genetically engineer and improve plants, animals and (soon) humans, we can better and better predict and protect ourselves against acts of gods (like rain, hurricane, volcanoes, mudslides, avalanches, floods, tornadoes, etc).

So, basicly we know nature A LOT to change our life from primitive cave existence to modern civilized activities. May be, we actually know it TOO MUCH to manage excessive nuclear forces to even completely eliminate ourselves and other forms of life from Earth?

Knowledge of math (natural laws) = light and power to manage and predict.

Lack of knowlege = ignorance, no power to affect things due to lack of understanding of nature, weakness, and as direct result - belief in all kind of supernatural, astrological and religious superstitions instead.