For both, we control almost nothing, we observe. To that end we build tools to observe. We want to observe to reject hypotheses or to get new insight on how nature behaves. In particle physics these are detectors, like the Super Kamiokande [1], which is just sitting there waiting for neutrinos to arrive from space. In the case of cosmology these are telescopes, radio telescopes and the like, waiting for photons, gravitational wave chirps to arrive from space.
