Over the past fifty years numerous ethical and political traditions, and positions and sub-positions, have emerged in the fields of animal and environmental ethics. In combination with inconsistent terminology and axiological variation, this has made it difficult for both novices and professional scholars to maintain an overview of these fields. Referring to the preliminary work of Kenneth Goodpaster, William Frankena and Kirsten Schmidt, this paper describes and explains a workable 3D method in which advantageous use is made of three dimensions (...) in ethical argumentation: “moral considerability”, “moral significance” and “moral practice”. The method is a useful research tool for at least three reasons: it allows us to systematically analyze, reconstruct, compare and criticize different normative positions in animal and environmental ethics; it helps ethical theorists to reflect on, and define, their distinctive positions; and it leads to the construction and development of a moral position with the desirable qualities of clarity, transparency, comprehensibility and completeness. First, the 3D method is introduced, and its historical context and origins outlined. Then the three dimensions of the method (moral considerability, moral significance, and moral practice) and their interrelations are considered. The paper concludes with some critical remarks and discusses the limits of the method. (shrink)