 A more recent challenge to reliabilism, due to Frise (2018), is the “temporality problem”. Reliabilists maintain that the justificatory status of a belief depends on the reliability of the process responsible for that belief. But, Frise points out, a process can be more reliable at one time than at another. To give one of Frise’s examples, weather forecasting has improved over time. So the process type, forming a belief based on the forecast is more reliable now than it was twenty years ago. This raises a question about the temporal parameters that we should use when evaluating reliability. Suppose we are evaluating whether a belief B is justified at a time t. Do we restrict our attention to whether the belief-forming process responsible for B is reliable at t? Or do we look at whether it has been reliable at all times up until t? Or all times that are temporally close to t? Or something else?