Why take part in ecumenical conversations?

In the light of my posts last week, especially the ones about the unity of God and diversity of creation and the image of God,  I came across this from the post Father Count - still counting in another blog.   

I have problems with ecumenism on two levels.  One is knowing the Protestant point of view on the subject, that “no one church possesses all the truth, but we possess the entire truth when we come together.”  Since the Orthodox Church does possess all the truth, it makes no sense to get together with people whose idea of “worship” comes dangerously close to worshipping themselves, since they continually “create” God in their own image and likeness.  Why would any Orthodox person want to go there?!

This view and similar ones are common in blogs written by Orthodox and Catholic bloggers, particularly in the States.  (Very few people seem to blog about ecumenism in the UK and if they did I would expect a greater proportion to be Protestant bloggers.)  The perspective on ecumenism I'm finding is very different to what I'm used to and so it is interesting to discover a very different emphasis, where leadership seems to be centred within Orthodox and Catholic traditions.  (These are first impressions, I'm sure I'll learn more as I read more.)

It is this 'Protestant view' that interests me and I wonder where it has come from.  To a degree I recognise it and my first inclination was to think (a) I'm a Protestant and don't believe that, and (b) but I could see some Protestants believing it.

The idea that the traditions don't individually have all the truth and need to come together to discover it seems questionable to me.  It is as if each tradition is a piece of a jigsaw puzzle and once we fit all the pieces together we'll get the right answer.  This cannot be right.  The churches in the mainstream ecumenical instruments in the UK recognise each other as part of the one holy catholic and apostolic church.  How can we be so if each tradition alone is only part of the picture?  Each tradition must have all that is necessary for salvation or else they would not be recognised as a Christian tradition.  Individuals might dissent from this belief but it is the position of all the mainstream Christian traditions. 

So, it may be true that Orthodox Christianity possesses all the truth but so does the Methodist and all the other traditions.  So, why ecumenism?

1. When I enter into conversation with other traditions, it throws light upon my own tradition.  As I reflect I learn more of my tradition, its history, theology and culture.  I can only conclude Methodism has all that is necessary for salvation, although there is always more for me to learn.  I learn this through dialogue with other traditions as they learn of their own tradition through dialogue with me and my tradition.
2. But there is more to be learned through conversation because it will inevitably lead us to new insights, ideas that have not been had before.  The world is bigger than our own traditions and it is when we look outwards, the interactions between our distinctive traditions may help us find new ways of addressing the issues that concern us today.

I'm not sure I understand exactly what the blog means about Protestants worshipping themselves.  As a Methodist I believe our foundation tradition, through John Wesley, addresses this criticism.  I will write about sanctification in future posts and I believe this doctrine shows how Methodists address the problem of idolatry. Idolatry is a problem for all Christians and I find it hard to see how any tradition can prevent its adherents from practising it other than by good instruction and guidance.