What physics concept does Dillard use to write about observing muskrats? How does she use it?

The "Principle of Indeterminacy," which basically states that one can not know both the velocity and the position of a particle. In the same way, Dillard says that a muskrat is like an electron. One can never know exactly where it may be. Scientists cannot actually observe a particle directly. They can only observe the effects of their observations. The principle of indeterminacy invalidates the notion of cause and effect. Dillard writes that for many physicists the realization that cause and effect is no longer valid leads the physicists to mysticism. Dillard believes that in applying this principle to the physical world, the logical conclusion is that "it is all touch and go."