It's amazing how adherence to the biblical doctrine of creation can lead to evangelism in the most unlikely of settings.
I was at a business function hosted by a university school of business (at The Establishment, for what its worth) and was chatting to a couple of people when the conversation swung to sustainability. I played a somewhat sceptical line to see where it would lead (I discussed economic drivers of production and consumption and wondered where the idea of sustainability fitted in).
One of the people there claimed that sustainability was a Value, not only because it would preserve the habitat we all relied upon, but even if there were no people it would be a Good. I asked how it would be a Good if there were no people to value the result: she said it would be Good for the earth; but, I said, the earth is not conscious, so how would the good be apprehended?
She had no answer and was at materialism's dead end. So I discussed that Good only had context in people, and had to be about conscious interactions; but if these interactions were the mere outcomes of material, the notion of Good having any real weight evaporated.
Of course, the conversation meandered, but it got to the point where I could point to the dichotomy: materialism took us to dust, which had no differentiable value, but the notion of value itself relied upon there being a means of differentiating values and this came from mind. If mind was basic, then there were real values; and thus was congruent with a real creator, mind who had will: matter therefore being an outcome of mind.
It wasn't the gospel by any means, it was too short a conversation, but it took her to an edge of her inarticulate materialism. I pray the next conversation with a Christian who obeys the word of God in its revelation of creation will move her thoughts closer to our redeemer.