Some atheists enjoy debating religion and have a lot of experience with traditional Christian doctrines, but they may find themselves unprepared for that Jehovah's Witness who comes knocking at their door. The views of The Watchtower Bible and Tract Society are different from those of most Protestants, so if you are going to discusses Watchtower Society doctrines and Jehovah's Witnesses' beliefs, you must understand what those differences are.
Explained here are 10 important doctrines which differ from traditional Christian beliefs and which will help you better understand and debate Jehovah's Witnesses
1. No TrinityWitnesses only believe in a single, solitary God and his name is Jehovah. Jesus, as Jehovah's son, is a separate individual second only to his father. The holy spirit (uncapitalized) is simply Jehovah God's active force. Whenever God causes something to happen, he uses his holy spirit to do it. The holy spirit is not an individual unto itself.
2. God did not Create the Universe DirectlyWitnesses believe that Michael the Archangel is the only thing which Jehovah created personally. Michael created everything else under Jehovah's direction. They also believe that Jesus was in fact Michael made flesh. Michael, now called Jesus, is second only to Jehovah in power and authority.
3. No Eternal DamnationWitnesses believe that Hell, as mentioned in the Bible, merely describes the grave after death. In some cases, it may also refer to everlasting destruction. Note that they reject the Christian belief in a human soul. Living things (including humans) do not have a soul, but instead they are souls in and of themselves.
4. Only the 144,000 go to HeavenWitnesses believe that only a select few - referred to as the anointed, or the "faithful and discrete slave class" - go to Heaven. They will serve as judges at Jesus's side. There are only 144,000 of the slave class in total. (Note that the total number of anointed recorded exceeds this number) Sometimes, a member of the anointed may have their position revoked by Jesus for some sin or other impropriety he disapproves of. When this happens, a new anointed is called. Witnesses are reminded to be the faithful and discrete slave in accordance with Jehovah's wishes because they are his representatives on Earth. The Society's views on the anointed tend to change every so often as the 1914 generation of anointed Witnesses gets older.
5. An Earthly Resurrection and ParadiseNon-anointed Witnesses expect to live forever right here on Earth. They have no "heavenly hope." It is believed that only faithful Witnesses will survive Armageddon and live to see Christ's Millennial Reign. Nearly everyone who ever lived will be resurrected and made young again, but this excludes those killed during Armageddon. The surviving Witnesses will train the resurrected to believe the Watchtower Society's teachings and to worship as they do. They will also work toward making the Earth a paradise. Any resurrected person that refuses to go along with this new arrangement will be killed permanently by Jesus, never to be resurrected again.
6. All non-Witnesses and "Worldly" Organizations are under Satanic ControlAnyone who is not one of Jehovah's Witnesses is a "worldly person" and therefore part of Satan's system of things. This makes the rest of us bad associates. All governments and non-Watchtower religious organizations are also seen as part of Satan's system. Witnesses are forbidden to involve themselves in politics or interfaith efforts for this reason.
7. Disfellowshipping and DisassociationOne of the Society's more controversial practices is disfellowshipping, which is a form of excommunication and shunning all in one. Members can be disfellowshipped for committing a serious sin or for a lack of faith in the Society's teachings and authority. A Witness who wishes to leave the Society may write a letter of disassociation. Since the penalties are basically the same, this is really just a request to be disfellowshipped.