Ever since the Second Vatican Council it is being increasingly realized that experiment and adaptation are continuing conditions of the life of the Church. But what precisely is an experiment in this context ? Karl Rahner has recently tried to answer this question and he concludes that since history as such is not really open to experimentation in the scientific sense, experiment must have a different meaning in the two contexts, and so the Church can learn nothing useful from a study of scientific experiments. In support of this view Rahner points out that an experiment in the Church is an event in the Church itself and so changes the Church, while no scientific experiment changes the physical world. Thus the meaning of experiment is quite different in the two cases.

In this he compares the subject of one activity with the object of another so the result is naturally misleading and unfruitful. The logical comparison shows a close similarity that deserves further study: just as a scientific experiment does not change nature, neither does an experiment in the Church change human nature; but just as a successful experiment in science is a stage in the growth of the understanding of the natural world by the scientific community, so a successful experiment in the Church is likewise an irrevocable stage in its onward spiritual pilgrimage.

In view of this close similarity it is not surprising that Rahner’s account of the place of experiment in the life of the Church is much closer to scientific experience than he recognizes and thus a further exploration of the analogy may prove useful.