Full Idea
Wiggins says that coincidence is possible only between objects of different kinds. Trees and cats coincide with aggregates of matter, but never trees with trees or cats with cats.
Gist of Idea
Objects can only coincide if they are of different kinds; trees can't coincide with other trees
Source
report of David Wiggins (Sameness and Substance Renewed [2001]) by Theodore Sider - Four Dimensionalism 5.3
Book Reference
Sider,Theodore: 'Four Dimensionalism' [OUP 2003], p.154
A Reaction
At first glance this sounds quite plausible, but I think this commitment to the priority of kinds produces huge confusion, given that we only derive our notions of kinds from inductions derived from individuals. Language perpetuates old inductions.