 Put simply, some elements of a veridical causal model are not involved in the production of the effect. Other elements are involved, but their influence can be neglected, provided the description of the effect is not overly fine-grained. For example, the gravitational forces of other planets may influence the trajectory of a rock thrown nearby the Earth’s surface. But these forces do not make a difference to whether or not the rock hits a fragile object. Hence, the kernel should not contain such forces. More generally, a kernel for \(E\) should not contain elements of \(M\) that are involved in the production of \(E\) without actually making a difference to it. This gives us a second reason for the requirement of generality.