 An obvious choice, endorsed by Monton (2006), who is critical of the argument from fine-tuning for design, and Collins (2009), who supports it, is the so-called counterfactual or ur-probability solution to the problem of old evidence, as defended by Howson (1991). The main advantage of this solution as applied to the argument from fine-tuning for design is that it allows to essentially preserve the argument, including \(\eqref{simpledes}\) and \(\eqref{likelihoods}\), with the sole refinement that one must consistently construe all prior probabilities \(P(\cdot)\), conditional and unconditional, as “ur-probabilities”, i.e., rational credences of some counterfactual epistemic agent who is unaware that the constants are right for life. Somewhat bizarrely, as Monton points out (2006: 416), such an agent would have to be at least temporarily unaware of her/his existence (or at least her/his existence as a form of life) because otherwise she/he could not possibly be unaware that the conditions are right for life. Tentative suggestions concerning the background knowledge that can reasonably be ascribed to such an agent are developed by Monton (2006: sect. 4) and Collins (2009: sect. 4.3).