William La Due describes modern Orthodox theological scholarship as split between a group of scholars that hold to a "strict traditionalism going back to Photius" and other scholars that are "not so adamantly opposed (to the filioque)". Vladimir Lossky asserted that any notion of a double procession of the Holy Spirit from both the Father and the Son was incompatible with Orthodox theology. Orthodox scholars who share Lossky's view include Dumitru Stăniloae, John Romanides and Michael Pomazansky. Sergius Bulgakov, however, was of the opinion that the filioque did not represent an insurmountable obstacle to reunion of the Eastern Orthodox and Roman Catholic churches.