Abstract
According to many orthodox Christian theologies Jesus is not merely sinless but impeccable: he not only did not sin but could not. This is puzzling because one can only sin by doing something else and, prima face, Jesus can do actions that you or I could do by which we would sin. I suggest that appearances to the contrary, Jesus cannot do a variety of actions that a merely human duplicate could do. His doing sinful actions is compossible with a range of empirical facts about his physical abilities and circumstances of the sort we ordinarily take into account in assessing what a person can do, but not with a wider range of theological facts concerning his divinity. Like Tim, Lewis’s time-traveler, who can kill Grandfather relative to facts about his immediate circumstances and abilities but not relative to a wider range of facts, Jesus ‘can’ in the ordinary sense sin, though he will not, but relative to a wider range of facts which obtain in virtue of his divinity, cannot.