As a scientist and a believer in human progress, I have been concerned about how well the established process of teshuvah (repentance) has worked. Yom Kippur after Yom Kippur - in fact, since the 11th century - we have recited the same confessional prayer, "Al Chet." If we were any good at repentance, shouldn't the list have changed in 1,000 years? Even if we don't want to change the ancient formula, shouldn't we be able to feel that we had eliminated or reduced at least a few on the list? Yet the list of sins remains the same, as does the ritual for expunging them. Why haven't we improved?