Robert Jastrow, a scientist who calls himself “agnostic” in religious matters, has written in God and the Astronomers (New York: Norton) the following:

A sound explanation may exist for the explosive birth of our Universe, but if it does, science cannot find out what that explanation is. The scientist’s pursuit of the past ends in the moment of creation. This is an exceedingly strange development, unexpected by all but the theologians. They have always accepted the word of the Bible, “In the beginning, God created the heaven and earth.” To which St. Augustine added, “Who can understand this mystery or explain it to others?” The development is unexpected because science has had such extraordinary success in tracing the chain of cause and effect backward in time.… Now we would like to pursue that inquiry farther back in time, but the barrier to further progress seems insurmountable. It is not a matter of another year, another decade of work, another measurement, or another theory; at this moment it seems as though science will never be able to raise the curtain on the mystery of creation. For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountains of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries.