Is it permissible to speak with an atheist without engaging in religious discussions?

A Muslim who apostatizes should be shunned and warned against, and not associated with until he repents, so that he may be deterred from his disbelief. If a dissolute person is shunned, then an apostate is even more deserving of shunning. The apostate should be invited to Islam and introduced to books and channels that combat atheism. If there is a benefit in speaking with him, there is no harm, provided one is cautious of temptation. As for the original disbeliever, he should be shunned, unless there is a benefit that necessitates speaking with him and inviting him to Islam.