Polkinghorne, J, Science and Providence, (London: SPCK, 1989) pp18-21 - see also God, Humanity and the Cosmos, p215-16. The difficulty is illustrated by the fact that Sallie McFague, one of the most eloquent exponents of the ‘embodiment image’, is able to give no account of divine action, beyond some vague talk of ‘spirit’. She describes her model as being ‘agential-organic’ (McFague, S, The Body of God (London: SCM Press, 1993) pp140f), but the aspect in which God is thought of as agent is never given substance.