radical reconstruction of tradition as attempted by Marcion. With the freedom that still prevailed Christianity was in danger of being resolved into a motley mass of philosophic speculations or of being completely detached from its original conditions. "It was admitted on all sides that Christianity had its starting-point in certain facts and sayings; but if any and every interpretation of those facts and sayings was possible, if any system of philosophy might be taught into which the words that expressed them might be woven, it is clear that there could be but little cohesion between the members of the Christian communities. The problem arose and pressed for an answer: What should be the basis of Christian union? But the problem was for a time insoluble. For there was no standard and no court of appeal." From the very beginning, when the differences in the various Churches began to threaten their unity, appeal was probably made to the Apostles' doctrine, the words of the Lord, tradition, "sound doctrine", definite facts, such as the reality of the human nature (flesh) of Christ, and the reality of his death and resurrection.[31] In instruction, in exhortations, and above all in opposing erroneous doctrines and moral aberrations, this precept was inculcated from the beginning: [Greek: apolipomen tas kenas kai mataias phrontidas, kai elthomen epi ton euklee kai semnon tes paradoseos hemon kanona] ("Let us leave off vain and foolish thoughts and betake ourselves to the glorious and august canon of our tradition"). But the very question was: What is sound doctrine? What is the content of tradition? Was the flesh of Christ a reality? etc. There is no doubt that Justin, in opposition to those whom he viewed as pseudo-Christians, insisted on the absolute necessity of acknowledging certain definite traditional facts and made this recognition the standard of orthodoxy. To all appearance it was he who began the great literary struggle for the expulsion of heterodoxy (see his [Greek: syntagma kata pason ton gegenemenon haireseon]); but, judging from those writings of his that have been preserved to us, it seems very unlikely that he was already successful in finding a fixed standard for determining orthodox Christianity.[32]