experimental scientist, was a man of profound Christian conviction. As he lay on his deathbed, he was asked by a visiting friend, “Sir Michael, what speculations have you now?” For a man who had spent his life making speculations about a vast array of scientific subjects, discarding some and establishing others, his response was robust: “Speculations, man, I have none! I have certainties. I thank God that I do not rest my dying head upon speculations for I know whom I have believed and am persuaded