The debate beween the defenders of free will and of free grace in Christian theology is an age-old one. Those who have argued that human salvation is by God's grace alone seem quite opposed to those who argue that God's grace requires the unaided cooperation of the human will if it is to be successful.

In such a situation the prospect of establishing a mediating position becomes attractive. This is what J. R. Lucas has recently attempted.2 Moreover, his proposal has the added interest and attraction of insisting that mistakes on both sides have been philosophical, mistakes about the nature of causality. According to Mr Lucas the Augustinian has mistaken causal importance for causal sufficiency. Pelagius was correct about the part played by free will in salvation, but wrong in attaching as much importance to that fact as he does, while Augustine is correct in the importance to be attached to God's grace, but wrong in thinking that emphasis on God's grace logically excludes human free will.