The aim of this dissertation is to provide a robust theory of environmental ethics which can offer nuanced accounts of value while evading the central problem of subjective disagreement that plagues other theories. The theory in question has many names, but the best abstraction of it can be found in the term "ontocentrism." Like pure biocentrism, this theory locates a monist center of value around which all other theorizations may orbit. Unlike biocentrism, however, this theory is not satisfied by anything short of the most basic commonality between valuable entities. That most basic value is existence, and it is taken to be the ground for all other values. This proposed theory, along with the methodology suggested, will be argued to be the next, if not final, step in theorization about environmental ethics. Due to the ubiquity of existence, however, this monism, as will be shown in detail later, paradoxically also appears to behave as a pluralist account of value would, wherein different positive accounts of value(s) are all affirmed. Therefore, despite being objectivist about value, it makes short work of the relativistic situations that are often brought to bear against objectivist accounts. This theory does not wish to abstract from the details of the world, and thus aim for some unattainable lack of bias, but rather it incorporates as many details about the world as possible such that any biases that may exist will be overwhelmed by the diversity of inputs which enter it. Any and all positive accounts of value have a prima-facie reason to be taken seriously, if not ultimately upheld. Since there is such a multiplicity of potential referents towards which value may be ascribed, there seems to be only, if one is not to impose preference on others, one way of impartially ascribing value; and that is equally. Thus, more complex entities will tend to have a greater number of potential referents of value, and therefore more value under this system. The intrinsic existential value of some specific entity can then be summed with the intrinsic existential value that that entity's continued existence will create or destroy in the specified future, often called extrinsic value, and this yields the total value that can inform our decisions.