In How to Count Animals, more or less, Shelly Kagan
sketches and argues for a hierarchical account of moral status.
Although the book is fairly lengthy at 304 pages of text, Kagan
is correct in calling it a sketch, since what this book provides
us with is a foray into one aspect that a comprehensive ethical
theory must include, in his view, if it is to be plausible. Even so,
the work that he does, if one accepts hierarchy, opens up many
different avenues to be further pursued in animal ethics.