This is good stuff worth some real discussion. To say that “missional” churches are the only viable expression is to miss the point I think. In a post Christian culture (and large parts of our culture are post Christian) viable expressions are missional as a truism. All other expressions will fade away. But viable expressions are not always missional in ways envisioned by Keller or anyone else.
For example – is discourse in the vernacular really missional? When I’ve listened to Keller, he does not really do this. In fact he retains useful terms and concepts but tries to teach them to his audience realizing that they likely have not been raised in the language. Over emphasis on discourse in the vernacular in our western culture usually (but not always) means a watered down presentation. Certainly there are examples where watered-down is not the appropriate description. But isn’t the point really to avoid us-them language and division rather than discourse in the vernacular?
On the last two point from Keller.
Aren’t “think Christianly” and “counter-cultural Christian community” two sides of the same coin? We will create a counter cultural Christian community if and only if lay people are trained theologically for public life and vocation – and if and only if the teachers (pastors) aim to make peers out of people. (Goes somewhat with Scot’s emphasis on “third way preaching/teaching).
Interesting to think about – I hope the post gets some discussion.

“Is it only bad news that the West is growing more and more Post-Christian? What benefit could this new setting bring to the church?”
Tony, thanks for these posts. This is a great question, even if I’d prefer to say ‘post-Christendom’ since I’m not too convinced that the West or any other fallen culture can really be ‘Christian’.
Benefits? – what follows is more a prayer than anything. I guess it all depends on how we discern what the Spirit of God is saying to us in the midst of change? But whatever the future, we need to go forward in faith not fear – or wanting to ‘run back’ to the security of the past.
Maybe a deeper trust in God rather than our own cultural power and strength in numbers? Maybe a renewed focus on mission rather than assumptions of a ‘come to us’ church. Maybe being more open to dialogue & listening to others outside the church from being a minority in a pluralist & secularising culture? Maybe increased humility borne from life on the margins rather than the centre? Maybe a renewal of humble evangelism in a culture which knows less and less of the Christian story and assumes Christianity is bad news? Maybe deeper prayer as we recognise there is a cultural shift going on far outside our control? Maybe a rediscovery of the gospel as good news and ‘public truth’ for all of life. Maybe the church will be spiritually renewed to incarnate the gospel in its community life, rather than be propped up by the crumbling pillars of Christendom.

RJS mentioned the “vernacular” issue — what that made me think of was how *some* in emerging and missional circles are advocating more liturgy, weekly Eucharist, etc. That would seem to collide head-on with Keller’s “vernacular” advocacy.
If we sing the Gloria Patri every week (heck, I’ve been in churches for 30 years and I’m not really sure what the part starting with “As it was” is supposed to mean), or say “the new covenant in my blood” every week, are we failing to be “missional”?

Something is missing here. Point #4 says we are to create counter-cultural churches regarding money, sex and power. But it says nothing of being counter-cultural regarding the racial segregation that is rampant in our churches and that some do not even think about.
Tim Keller has done good work in this regard in his church, but if this primary sin of our society is not addressed in smaller churches in less metropolitan places, the Missional Church, of which I am a supporter, will fail. I think both of Chris Rice’s essay on two churches in Durham and our congregation here in Grand Rapids, where our congregation is working hard in some regards but has a long way to go with learning how to work and serve alongside their brothers and sisters.
Peace,
Randy

AHH-
“…how *some* in emerging and missional circles are advocating more liturgy, weekly Eucharist, etc. That would seem to collide head-on with Keller’s “vernacular” advocacy.”
On the contrary- I think it speaks to the vernacular issue well. Many outside (and inside) the church have at least some knowledge of such practices, and expect/want it. It brings to mind the recent study that showed how the unchurched would rather worship in a traditional place of worship than in a modern, business-like building.
Of course this, and many of the things Keller mentions, have to do with context. Keller regularly reminds people to keep in mind that he is speaking from a NYC context, and that we should adapt to our own circumstances accordingly.

RJS says, “We will create a counter cultural Christian community if and only if lay people are trained theologically for public life and vocation…”
Maybe. I’m more inclined to think that our model of “theological vocational training” is part of the problem that perpetuates our stark Constantinian lay-clergy duality.
The Jesus movement was counter-cultural not because it trained religious authorities, but because it entrusted all people as “priests,” regardless of academic or vocational achievement.
Rather than encouraging the professional / amateur duality, let’s find ways to flatten our inherited religious hierarchies and encourage all-body participation.