  Computer simulations of the formation and evolution of large scale structure
in the universe are integral to the enterprise of modern cosmology.
Establishing the reliability of these simulations has been extremely
challenging, primarily because of epistemic opacity. In this setting,
robustness analysis defined by requiring converging outputs from a diverse
ensemble of simulations is insufficient to determine simulation validity.
Instead, we propose an alternative path of structured code validation that
applies eliminative reasoning to isolate and reduce possible sources of error,
a potential path that is already being explored by some cosmologists.
