Guide Mentor
Character Role Analysis
The Self-Taught Man
The Self-Taught Man takes it upon himself to sit Antoine down in a restaurant and lecture him about how love for humanity will take away all of his suffering. Antoine doesn't buy what the STM is selling him, which really makes the STM a failed mentor.
Add to this the fact that the STM likes to make sexual advances on young boys, and the dude's credibility is pretty much shot. After all, Sartre believes that the individual ultimately has total control over what he or she believes, so the role of guide or mentor in this book was really destined to fail.
For Sartre, it's up to each one of us to decide for ourselves what we think, and there's no point in looking for guides or mentors. Apart from Sartre, that is. He's more than happy to be our philosophical mentor.