KEENER ON QUASI-CONTRACTS, 221 because in the last analysis both reduce themselves to the same method, the method of exclusion. Whether these two theories as to the learned author's classifica- tion, however, are or are not substantially identical, I submit not only that the arguments formally adduced by him in support of it are technically insufficient, but also that either theory is substan- tially unsound and unscientific. • III. The main purpose of the treatise under review is to explain as a principle of jurisprudence the doctrine of unjust enrichment and thereafter to examine it in its various applications. The learned author does not attempt to justify it or to explain its origin. He assumes without argument that it is self- evidently true and also that it is valid as a juridical principle. This is unfortunate, for weighty reasons may be adduced to prove that neither of these propositions is true. The learned writer thus states this principle : " No one shall be allowed to enrich himself unjustly at the expense of another." ^ Inasmuch as he is dealing with a proposition of law (using that word in its largest sense as including equity and meaning the whoFe power of the Courts to remedy wrongs), it is in no degree a perversion of his meaning to mark the fact more clearly by insert- ing the words *' by law " after the word " allowed," so that the proposition will read : No one shall be allowed by law to enrich him- self unjustly at the expense of another. Indeed this addition is necessary to redeem the proposition from the charge of being ethical merely and not juridical. It is a valid criticism of the learned author's phraseology that it does not, even as amended, fully convey his meaning. He has stated ^ that the obligation of which he treats is affirmative, not negative, requiring an active performance, not a passive forbear- ance, and it is by this mark that he distinguishes it from torts. His proposition on the other hand, the form into which he casts his juridical principle, is a mere prohibition, to which conformity is, as he says of torts, only forbearance. This point seems to have escaped him, for he does not define the active duty, leaving it, on the contrary, to be inferred by his readers. Taking the proposition as it stands, however, it is open to a still more fundamental objection. If it be true that no one shall be 1 Page 16.
