Secondly, amid all the varieties of thought referred to, complicated as they are by the eager advance of some and the clinging to survivals by others, there are two notes to be found undeniably, if unequally, characteristic of Unitarianism. It is both _rationalist_ and _mystical_. If the historian seems more attentive to the former than to the latter, this must not be taken as indicating their relative importance. Obviously, it is easier to record controversies than to unfold the wealth of profound conceptions. Perhaps we may fairly suggest the true state of the case by the mere juxtaposition of such earlier names as Socinus, Bidle, and Locke, with those of Channing, Emerson, and Martineau; or by a reference to the earlier Unitarian hymns in contrast with those of the later stages. SOME TERMS EXPLAINED A brief explanation at the outset may help the reader to follow more intelligently the history of Unitarianism. As is well known, the chief issue between Trinitarians and Unitarians arises in connection with the relation of Jesus Christ to God, questions concerning the Holy Spirit being usually less discussed. There are consequential issues also, bearing upon man's nature, atonement, salvation, and other subjects, but these call for no remark here. In its full statement, as given for instance in the 'Athanasian Creed,' the Trinitarian dogma presents the conception of Three 'Persons' in One God--Father, Son, and Holy Spirit--'Persons' with different: functions, but all equal and co-eternal. The Eastern (Greek Orthodox) Church differs from the Western (Roman Catholic) in holding that the Third Person 'proceeds' from the Father alone; the Western adds--'and from the Son' (_filioque_). The full dogma as given in the 'Athanasian Creed' is not thought to be earlier than the fifth century; debates as to the 'two natures' in Christ, and the 'two wills,' and other abstruse points involved in the dogma, continued for centuries still. At an earlier period discussion was carried on as to whether the Son were of the 'same substance' (_homo-ousion_) or 'similar substance' (_homoi-ousion_) with the Father. The latter view was held by Arius and his party at the Council of Nicaea, A.D. 325. Athanasius held the former view, which in time, but only after many years of controversial strife and actual warfare, became established as orthodox. The Arians regarded the Son, as a subordinate being, though still divine. Another variety of opinion was put forth by Sabellius (_c._ 250 A.D.), who took the different Persons to be so many diverse modes or manifestations of the One God. This Sabellian idea, though officially condemned, has been often held in later times. Socinianism, so far as regards the personality and rank of Christ, differed from Arianism, which maintained his pre-existence, though not eternal; the Socinian doctrine being that the man Jesus was raised by God's approving benignity to 'divine' rank, and that he thus became a