Abstract
New mechanists forward an influential account of mechanisms in which entities (or parts) and their activities are organized so as to produce the phenomenon that calls out for explanation; and to explain is to describe that mechanism. However, critics charge that new mechanists have not provided a standard for identifying and individuating parts that blocks gerrymandered parts. To remedy this, I defend a carving principle that justifies the standard parts that are included as components of mechanistic explanations. My account grounds good parthood in robust explanatory relations I call the explanatory mosaic of science.
