1. Epistemological
This isn't news, but truth claims are more difficult in modernity. Particularly those outside of the range of science. Collectively, we've lost the meta-narrative (the big overarching story that shaped everyone's worldview) and have traded it in for more particular and local stories and perspectives. Big T Truth has been lost to little t truths. And this move isn't all bad. The stories of the weak and marginalized (their small t truths that were being written out of the history books by the Big T Truth of Empire) are slowly being recovered.
Doubters tend to flourish in the modern context. The fractured epistemological situation of modernity (often called “postmodernity”) demands a degree of epistemic humility. Doubters are very comfortable with this. Doubters tend to shy away from shouting meta-narratives at people who don't believe in meta-narratives. That is, rather than lamenting the modern situation, as the fundamentalists do (“No one believes in Truth anymore!”), the doubters will “get” the modern person and, due to certain shared sympathies, be more likely to articulate the faith in a way that makes sense to outsiders. Doubters trade in paranoid shouting for intelligible conversation.
via Experimental Theology: The Gifts of Doubt.