Conversation so far:
What did this do?
Roberts and the Seth Material have attracted critiques from outside the paranormal community.
What was the worst part of this?
The poet Charles Upton, in his collection of essays titled The System of Antichrist, posited that Roberts multiplied the self due to a fear of death.
What did this lead him to try?
His opinion was that the Seth texts are based on a misunderstanding of both Christianity and of Eastern religions.

Question: What did they lead them to do?
Self-contained rewrite: What did Charles Upton's critique of Jane Roberts lead Roberts to do?