In which conditions does the human species endow itself with a series of obligations aimed at orienting its relationship with non-human species? In my paper I shall try to answer this question by formulating two divergent theses. According to the first thesis (§ 1) the conditions of possibility for these obligations reside in a prescriptive dimension, ie authoritative. This thesis is articulable by distinguishing two kinds of authoritative source, respectively of transcendent (§ 1.1) and immanent type (§ 1.2). Here the awareness of the proximity between the animal species doesn’t seem to play an explicit role. The second kind of thesis (§ 2) identifies as a condition of possibility for these obligations a certain cognitive experience: ...