One error in particular we must be on our guard to avoid. We said above that both the socialists and the Christian economists are agreed in their desire to reintroduce justice into economic life. We must not conclude, however, that the aims of these two schools are identical. One very frequently meets with the statement that the teachings of socialism are nothing more or less than the teachings of Christianity. This contention is discussed in the following pages, where the conclusion will be reached that, far from being in agreement, socialism and Christian economics contradict each other on many fundamental points. It is, however, not the aim of the discussion to appraise the relative merits of either system, or to applaud one and disparage the other. All that it is sought to do is to distinguish between them; and to demonstrate that, whatever be the merits or demerits of the two philosophies, they are two, and not one. SECTION 4.--DIVISION OF THE SUBJECT The opinion is general that the distinctive doctrine of the mediæval Church which permeated the whole of its economic thought was the doctrine of usury. The holders of this view may lay claim to very influential supporters among the students of the subject. Ashley says that 'the prohibition of usury was clearly the centre of the canonist doctrine.'[1] Roscher expresses the same opinion in practically the same words;[2] and Endemann sees the whole economic development of the Middle Ages and the Renaissance as the victorious destruction of the usury law by the exigencies of real life.[3] However impressed we may be by the opinions of such eminent authorities, we, nevertheless, cannot help feeling that on this point they are under a misconception. There is no doubt that the doctrine of the canonists which impresses the modern mind most deeply is the usury prohibition, partly because it is not generally realised that the usury doctrine would not have forbidden the receipt of any of the commonest kinds of unearned revenue of the present day, and partly because the discussion of usury occupies such a very large part of the writings of the canonists. It may be quite true to say that the doctrine of usury was that which gave the greatest trouble to the mediæval writers, on account of the nicety of the distinctions with which it abounded, and on account of the ingenuity of avaricious merchants, who continually sought to evade the usury laws by disguising illegal under the guise of legal transactions. In practice, therefore, the usury doctrine was undoubtedly the most prominent part of the canonist teaching, because it was the part which most tempted evasion; but to admit that is not to agree with the proposition that it was the centre of the canonist doctrine. [Footnote: 1 _Op. cit._, vol. i. pt. ii. p. 399.] [Footnote: 2 'Bekanntlich war das Wucherverbot der praktische Mittelpunkt der ganzen kanonischen Wirthschaftspolitik,' _Op. cit._, p. 8.]