This is the final version. Available from the publisher via the link in this recordhis article offers a cognitive framework for thinking about the confluence of uncertainty and the IHL rules governing targeting. In abstract discussions, the tendency has been to understand the requisite level of certainty for engaging a target as a particular threshold, that is, as “certain enough” to satisfy the requirement to confirm a target as a military objective, qualify harm as collateral damage or military advantage that must be factored into the proportionality calculation, or require the taking of feasible precautions in attack to minimize harm to civilians and civilian objects. In our view, this approach neither reflects targeting practice,...