Paul and the Church?

Chris Tilling writes:

The famous German theologian Ernst Käsemann wrote:"[Paul] the apostle is not interested in the church per se and as a religious group. He is only interested in it as far as it is the means whereby Christ reveals himself on earth and becomes incarnate in the world through his Spirit." (Perspectives on Paul. Translated by Margaret Kohl. Philadelphia; Fortress, 117)

Isn't that going a bit far? Doesn't this present an un-Pauline either/or? But Käsemann's distinctions raise another interesting question: Does 'Christ reveal himself on earth and become incarnate in the world through the Spirit' outside the religious community?If so, then in what sense is the Church the 'body of Christ' if it fails in this task? And what counts as failure? Does it then cease to be the Church? Is Augustine's distinction between the visible and invisible Church the only option?

My theological answer to this would be that the Spirit is at work in the world leading people to the Church. In Paul's thinking, the Church is always of great importance. But how would one demonstrate that my theological answer was indeed Paul's view? Is one going to turn to Acts to see God at work amongst the Gentiles?

This is a good brain teaser... Thanks Chris! Now if we could only figure out why on earth one would call their blog "brainpoo"? But that appears to be another metaphysical conundrum...