The major schools of thought can be broken down into biocentrism, sentientism, ratiocentrism and anthropomorphism (weak and strong). In attempting to discover which of these views is most justified, it is necessary to understand the basic ideas each school of thought represents.
Biocentrism is, roughly speaking, a system in which the criterion for inherent worth is based upon the simple-seeming criterion of whether one lives or not. Because all living things have the right to exist, we, as thinking beings, hold moral responsibility to ensure that we do not interfere with this right. “[Taylor] contends that in addition to our moral obligations toward our fellow humans, we also owe duties to wild living things in their own right … He agrees with Goodpaster’s argument that one can deny that non-humans have rights and yet hold that they are moral patients toward whom moral agents have duties and responsibilities” (Kocer, 2001). Being the center of a life force is grounds enough to fulfill to the biocentrist viewpoint, but this introduces problems as one must consider that all life forms must hold inherent worth equally – the human as well as the cockroach – despite obvious differences in understanding and awareness.
As even Taylor hints, there must be something more to the question than simply the idea that one respirates and reproduces. This is where the ideas of sentientism arise. While philosophers such as Singer suggest that this term is applied to any creature that demonstrates capacity to feel pleasure or pain, “the term ‘sentient’ refers more broadly to consciousness of something or other, rather than to consciousness of pleasure and pain specifically” (Jamieson, 2003: 192). However, when it is applied in this sense, it is usually limited to the view of something being able to express it is feeling pleasure or pain. Under this view, things gain inherent