Well my field is history. Sapeins is correct.
Fantastic. Then perhaps you can supply some sources that indicate there is anything to this "two contemporaneous source" nonsense. I tried going through some of my sources but I couldn't seem to locate a single historian, classicist, Near-Eastern scholar, archaeologist, NT scholar, or any other specialist in any relevant field who mentions this made-up criterion:
Akenson, D. H. (2000).
Saint Saul: A Skeleton Key to the Historical Jesus. Oxford University Press.
Barnard, A. (2000).
History and Theory in Anthropology. Cambridge University Press.
Buckley, T. (2010).
Aspects of Greek History 750323BC: A Source-Based Approach. Routledge.
Byrskog, S. (2002). Story as History, History as Story: The Gospel Tradition in the Context of Ancient Oral History. Brill Academic.
Chantraine, P. (1984).
Morphologie Historique du Grec. Klincksieck.
Dillon, M., & Garland, L. (2000).
Ancient Greece: Social & Historical Documents from Archaic Times to the Death of Socrates. (3rd Ed.). Routledge.
Erskine, A. (Ed.). (2009).
A companion to Ancient History. Wiley-Blackwell.
Forsythe, G. (2005).
A Critical History of Early Rome: From Prehistory to the First Punic War. University of California Press.
Freedheim, D. K., & Weiner, I. B. (Eds.). (2003).
Handbook of Psychology:
History of Psychology (Vol. I). Wiley-Blackwell.
Grant, M. (1977).
Jesus: An Historian's Review of the Gospels. Scriber's.
Habermas, G. R. (1996).
The Historical Jesus: Ancient Evidence for the Life of Christ. College Press.
Kretzmann, N., & Kenny, A. (Eds.) (1982).
The Cambridge History of Later Medieval Philosophy: From the Rediscovery of Aristotle to the Disintegration of Scholasticism, 1100-1600. Cambridge University Press.
MacDonald, M. Y. (2004).
The Pauline Churches: A Socio-Historical Study of Institutionalization in the Pauline and Deutrero-Pauline Writings (
Society for New Testament Studies Monograph Series Vol. 60). Cambridge University Press.
Marincola, J. (Ed.). (2009).
A Companion to Greek and Roman Historiography (Vols. I & II). Wiley-Blackwell.
Meier-Brügger, M. (2002).
Indogermanische Sprachwissenschaft. Walter de Gruyter.
Orser, C. E. Jr. (2002).
Encyclopedia Of Historical Archaeology. Routledge.
Patrich, J. (2011).
Studies in the archaeology and history of Caesarea Maritima: Caput Judaeae, Metropolis Palaestinae (
Ancient Judaism and Early Christianity, Vol. 77). Brill.
Price, B. (Ed.). (1997).
Ancient Economic Thought (
Routledge Studies in the History of Economics, Vol. 13). Routledge.
Rheinberger, H. J. (2007).
Historische Epistemologie:Zur Einführung. Hamburg: Junius.
Shanske, D. (2006).
Thucydides and the Philosophical Origins of History. Cambridge University Press.
Schaps, D. M. (2011).
Handbook for Classical Research. Routledge.
Stigler, S. M. (1986).
The History of Statistics: The Measurement of Uncertainty before 1900. Harvard University Press.
Theißen, G., & Merz, A. (2011).
Der historische Jesus: ein Lehrbuch. Vandenhoeck & Ruprecht.
Tucker, A. (2004).
Our Knowledge of the Past: A Philosophy of Historiography. Cambridge University Press.
Tucker, A. (Ed.) (2011).
A Companion to the Philosophy of History and Historiography. Wiley-Blackwell.
Watkins, C. S. (2007).
History and the Supernatural in Medieval England (
Cambridge Studies in Medieval Life and Thought- Fourth Series). Cambridge University Press.
Wills, L. M. (1997).
The Quest of the Historical Gospel: Mark, John and the Origins of the Gospel Genre. Routledge.
We could keep going. There's the several volume
Cambridge Ancient History series, countless Handbooks & Companions (Blackwell's, Routledge's, Cambridge, etc.), ~60,000 books on the historical Jesus written in the 19th century (and many, many times that written in the past century), innumerable peer-reviewed papers in journals & sources like conference proceedings, graduate textbooks and reference materials for historians on historical methods, etc. Yet nowhere do we find such a simplistic, dogmatic, and utterly baseless criterion like "two contemporaneous sources" (especially given that "contemporaneous" is improperly defined; a contemporaneous source, particularly in antiquity, refers to the author/witness not the date of composition).