The latest date to which an undated, or disputed, writing can be assigned is that when the marks of its employment by others, or influence upon them, become undeniable. This is termed the 'external' evidence. The earliest date, conversely, is that to which we are brought down by references in the book itself to antecedent and current events, and writings, or by undeniable marks of their influence. This is termed the 'internal' evidence. Counting tradition as part of the external evidence, modern scientific criticism is able to fix within a few decades the origin of all the New Testament writings, without incurring opposition even from the apologist. No scholar now dreams of adopting any other method of proof, whatever his doctrinal proclivities. The overwhelming majority are agreed that the period covered, from the earliest Pauline Epistles to the latest brief fulminations against Gnostic Doketism and denial of 'resurrection and judgment,' is included in the century from A.D. 50 to 150. Baur's conception of the course of events in this momentous century has been described as a theory of historical progress by fusion of opposites in a higher unity. The Hegelian scheme of thesis, antithesis and synthesis had in fact some justification in the recognized phenomena of the development of Christianity. It had sprung from Judaism, overcoming the particularism of that still nationalistic faith by the sense of its mission to the world at large. The conflict acknowledged in all the sources and most vividly reflected in the great Epistles of Paul to the Galatians, Corinthians and Romans, a conflict between those who conceived Christianity as a universal religion, and those who looked upon it as only a reformed, spiritualized and perfected Judaism, was the characteristic phenomenon of the first or apostolic age. It was the struggle of the infant faith against its swaddling bands. The critical historian is compelled to estimate all later, anonymous, accounts of this development in the light of the confessedly earlier, and indubitably authentic records, the four great Epistles of Paul; for these simply reflect the actual conditions, and are not affected by the later disposition to idealize the story. Thesis and antithesis were therefore really in evidence at the beginnings.