Much of modern physics has been about exploring inherently invisible things, which seem to be far more common than the obvious things we experience with our senses. Yet these invisible things follow rigorous laws that allow us to test their existence in many ways. Here is a very short list of some of the "invisible" things that we routinely work with.
If confirmed, the recently detected potential ripples from the Big Bang represent an imprint on the cosmic microwave background by gravitational waves. Those gravitational waves are produced through a quantum process, providing, for the first time (again, if confirmed), evidence that gravity is governed by quantum mechanics. This point cannot be overemphasized.
Einstein believed in something like Spinoza's "God": a powerful entity that transcends the world. To Einstein, "God" was the maker of the laws of physics that he, Einstein, saw as his life's role to uncover. This is far from the "God" of organized Western religions, to be sure, but it is equally far from Lawrence Krauss "universe from nothing."