The prescription of meat abstinence has rules that belong to a real System describing the analogical structure of the cosmos created by God. A sub-set of this System defines the rules of the sacrifices as analysed by St Thomas.
Some texts indicate a complex semiology of the immolated objects. These objects have a double "meaning": first they are submitted to the rules of the contemporary tradition (litteral meaning) and secondly, they prefigure the perfect Object, Christ Himself (metaphorical meaning). The System is to be diachronically interpreted, as it is shown by the sacrifice of Isaac. It appears as a double stage System: as Isaac is replaced by an animal, the animal will be replaced by the Son of God. This is the story of substitution -a concept of the philosopher Emmanuel Lévinas.
The texts indicate other constraints on the choice of the animal in order to respect the analogy between the fault to be expied and the object, for example.
This kind of hermeneutics makes possible an analysis which suggests the sacrifice for the other by the immolation of the subject himself in-stead of the object. Such an ethics is currently defined by contemporary philosophers.