The door's being shut caused the room to be wanner. As we can also say, a set of conditions or events which included the door's being shut caused the room to be warmer. The set of conditions or events. whatever is to be said more carefully of their ontological category, and their closer specification, can be called a causal chrwnslance. The question of causal priority, as it is named, is the question of analysing or elucidating the difference or asymmetry between cause and causal circumstance on the one hand, and, on the other hand, their effect. David Sanford does not like my answer1 and sticks to his own more original one2. I should like to say briefly why