He believed in the unity of the Godhead and vehemently disagreed with any attempt at division of the personalities or personages of the Father, Son, and Holy Spirit in the Christian Church.
He was opposed by Tertullian in his tract Against Praxeas (Adversus Praxean), and was influential in preventing the Roman Church from granting recognition to the New Prophecy.
His name in the list of heresies appended to the "De Praescriptionibus" of that writer (an anonymous epitome of the lost "Syntagma" of Hippolytus) is a correction made by some ancient diorthotes for Noetus.
Monarchianism had sprung up again, but Tertullian does not mention its leaders at Rome, and directs his whole argument against his old enemy Praxeas.
Praxeas is mentioned in the Belgic Confession (1562) as and example of "certain false Christians and heretics... who were rightly condemned by the holy fathers.