that he did not know when the end would come, [ 16 ] and made no public comment after October 21 passed without his predicted apocalypse. [ 17 ] In March 2012 Camping "humbly acknowledged" that he had been mistaken, that his attempt to predict a date was "sinful," and that his critics had been right in pointing to the scriptural text "of that day and hour knoweth no man". He said he was searching the Bible "even more fervently... not to find dates, but to be more faithful in our understanding." [ 18 ] On May 23, 2011, Harold Camping stated that May 21 had been a "spiritual" Judgment Day and that the Rapture would occur on October 21, 2011, together with the destruction of the world. [ 22 ] [ 23 ] In a web posting titled "What happened on May 21?", Family Radio explained "Thus we can be sure that the whole world, with the exception of those who are presently saved (the elect), are under the judgment of God, and will be annihilated together with the whole physical world on October 21, 2011, on the last day of the present five months period." [ 23 ] Camping presented several numerological [ 25 ] arguments, which he called biblical "proofs", in favor of the May 21 end time. A civil engineer by training, Camping stated he had attempted to work out mathematically-based prophecies in the Bible for decades. In an interview with the San Francisco Chronicle he