Authors:

There is a danger there - a very real danger to humanity. Consider, Watson, that the material, the sensual, the worldly would all prolong their worthless lives. The spiritual would not avoid the call to something higher. It would be the survival of the least fit. What sort of cesspool may not our poor world become?

Arthur Conan Doyle (1989). “Sherlock Holmes: The Complete Stories”, p.1012, Wordsworth Editions
There is a danger there - a very real danger to humanity. Consider, Watson, that the material, the sensual, the worldly would all prolong their worthless lives. The spiritual would not avoid the call to something