I have argued before that John Thomas did not "discover" anything. All the doctrinal distinctives held by Christadelphians can be traced to groups which were either contemporary to John Thomas or predated him. In fact, I will demonstrate in some future articles that John Thomas acquired all his major doctrines from groups or individuals with whom he was in contact. That's not to say these doctrines are either right or wrong - I simply want to look at the influences which acted on John Thomas and the early Christadelphians in shaping the denomination.
I am not alone in saying that John Thomas was an eclectic who acquired (rather than 'discovered') ideas. One of Thomas's early converts was Joseph Chamberlin, a Methodist minister who left Methodism and became a Christadelphian. In his weekly Christadelphian magazine The Aeon Chamberlin wrote:
Another distinguishing fact to be mentioned in regard to Dr. Thomas is, he was not remarkable for the enunciation or discovery of any ONE great truth. There is no one great doctrine which we can hang about his neck, as “justification by faith” is connected with the name of Luther, or “sanctification” with that of Wesley. He did not so much discover a brilliant star as give us a true astronomy; it was not so much the announcement of an unknown truth as the marvellous systematisation of many truths, and the disentanglement of the divine purposes from the web of error which tradition through centuries has woven…
So, nearly every teaching to be found in Dr. T.’s final publications may be found in some fragmentary form or another up and down the theological literature of the world, but nowhere can be found that harmonious system in which these parts are seen crystalising together…Sketches of John Thomas, M.D.
Joseph Chamberlin, The Aeon, April 10, 1885