By that name, probably in Egypt, although many of the ideas were current around the Mediterranean, probably for centuries before. Hints of it are in the New Testament ' Ye shall know the truth, and the truth shall make you free' (John 8:32), 'For the gate is small and the way is narrow that leads to life, and there are few who find it' (Matthew 7:14). Mystery cults of many descriptions existed, that laid claim to some secret 'knowledge', and some of these seem to relate to what later was called Gnosis.
The opponents of Gnosticism were primarily early Christian leaders and theologians, such as Irenaeus and Tertullian. They argued against Gnosticism's belief in secret knowledge and its rejection of the material world, emphasizing instead the importance of orthodox Christian doctrine and the belief in a loving creator God.
The origin of Gnosticism is generally believed to come from 3 main sources: Much of its philosophical tendencies came from Platonism, speculations on the origin of evil may have come from the Persian religion and the Buddhism of India may have been the origin of the doctrine of antagonism between matter and spirit. Gnosticism was named for "gnosis = knowledge" and was mainly concerned with the origin of sin rather than how one is saved from sin.
Gnosticism does not have a single founder as it emerged from diverse religious and philosophical influences in the ancient world. However, it is believed to have been shaped by various early Christian and Jewish sects, as well as elements of Hellenistic and Persian mysticism.
The very early days of Christianity apparently saw considerable diversity within the Christian community, as evidenced by the comments of authors such as Paul and Matthew. It may be that the earliest Christian sect was called the Ebionites, however, the Ebionites soon faded from history. Most early Christian sects are generally known today as Catholic-Orthodox Christianity and Gnosticism. We can not really say whether Gnosticism preceded the Catholic-Orthodox Christian faith, or the other way around, although modern churches do insist that Gnosticism arose after Catholic-Orthodox Christianity. However, Gnosticism was never a centalised faith, and never had a strong hierarchy, so was at a disadvantage against the Catholic-Orthodox Christian faith. When Emperor Constantine gave state patronage to Catholic-Orthodox Christianity and authorised it to take over the assets of the Gnostic Churches, the Gnostic Churches were ultimately doomed. The Great Schism of 1054 CE saw Catholic-Orthodox Christianity finally split into the Roman Catholic and the Orthodox branches, which are equally old.
The pneumatics ("spiritual", from Greek πνεῦμα, "spirit") were, in gnosticism, the highest order of humans as opposed to hylics. The Pneumatic saw himself as escaping the doom of the material world via the secret knowledge.
Gnosticism can be read about in many books. The Gnostic Society has their own Library in which everything about the Gnosticism can be learned or studied.
there is no scientific basis for Gnosticism or orthodox (mainstream) Christianity.
Simon Magus
Pneuma
No book in the bible addresses Gnosticism, you are looking for Against Heresies as written by a father of the church, Irenaeus.
The opponents of Gnosticism were primarily early Christian leaders and theologians, such as Irenaeus and Tertullian. They argued against Gnosticism's belief in secret knowledge and its rejection of the material world, emphasizing instead the importance of orthodox Christian doctrine and the belief in a loving creator God.
Test
Deirdre Joy Good has written: 'Reconstructing the tradition of Sophia in Gnostic literature' -- subject(s): Gnosticism, Wisdom (Gnosticism) 'Mariam, The Magdalen, And The Mother'
Ithamar Gruenwald has written: 'Messiah & Christos' 'From apocalypticism to Gnosticism' -- subject(s): Apocalyptic literature, Gnosticism, History and criticism, Judaism, Merkava in rabbinical literature, Mysticism
Mary Ann Donovan has written: 'Irenaeus' teaching on the unity of God, and his immediacy to the material world, in relation to Valentinian Gnosticism' -- subject(s): Gnosticism, Valentinians
Daniel L. Hoffman has written: 'The status of women and Gnosticism in Irenaeus and Tertullian' -- subject(s): Women in Christianity, Gnosticism, Social conditions, History, Women
The common belief is that Gnosticism originated as a branch of Christianity. There are some theories that claim the central ideas of Gnosticism existed before the birth of Christ. These ideas, of a dualistic religion (two Gods), still prevail today in modern Christianity with the teachings of one supremely good God of Heaven and one sinful, loathsome God of Hell.