In what work does Thomas Merton discuss atheists or people who do not accept faith?

I vaguely recall (from some lecture or reading) that supposedly somewhere in Merton's writings he comments on people who struggle with accepting faith. I'm looking for a passage where he is describing the case of those who feel obliged to be intellectually honest about their faith and thus struggle with their inability to accept the Christian teaching. Also a passage where Merton is expressing sympathy, understanding and maybe even some admiration for these people. Can anyone provide a quote or reference? I have already checked the *Apologies to the Unbeliever* and it is not what I am looking for.