 The major premise is a “maxim, a general rule of living,” assumed at some other point and remembered on the present occasion. The minor premise is based “upon an exact observation of the present circumstances and on the conviction that they fully agree with requisite properties A.” As in mathematics, the doctrine of morals divides into two parts, the theoretical (instructional) and the practical (applied), where the former conveys the general rules of living that serve as the major premises and the latter their application in a particular case. Mendelssohn submits that it is not difficult to prove “with geometric rigor and trenchancy” the general principles of ethics, i.e., the rational principles that prescribe what to do and to leave undone. Nothing is clearer or more compelling, he observes, than Marcus Aurelius’ conclusion that these principles follow from what is common to us as rational creatures. Because human beings have a common power of making value judgments (Beurtheilungskraft), all their judgments about good and evil rest upon the same ground, diverging from one another only to the degree that their insight does. There are accordingly “universal ground-rules” (what Mendelssohn also dubs “laws of nature”) according to which human beings are supposed to decide what to do and leave undone. Moving freely between the singular and the plural in this regard, Mendelssohn refers without qualification to both “this universal law of nature” and “laws of nature,” but this looseness can probably be attributed to the fact that he entertains three ways of proving and thus articulating “the first law of nature.”