《福尔摩斯探案集·蓝宝石案》第7节
“Well, that is clear enough, certainly. But how about the foresight and the moral retrogression?” Sherlock Holmes laughed. “Here is the foresight,” said he putting his finger upon the little disc and loop of the hat-securer. “They are never sold upon hats. If this man ordered one, it is a sign of a certain amount of foresight, since he went out of his way to take this precaution against the wind. But since we see that he has broken the elastic and has not troubled to replace it, it is obvious that he has less foresight now than formerly, which is a distinct proof of a weakening nature. On the other hand, he has endeavoured to conceal some of these stains upon the felt by daubing them with ink, which is a sign that he has not entirely lost his self-respect.” “Your reasoning is certainly plausible.” “The further points, that he is middle-aged, that his hair is grizzled, that it has been recently cut, and that he uses lime-cream, are all to be gathered from a close examination of the lower part of the lining. The lens discloses a large number of hair-ends, clean cut by the scissors of the barber. They all appear to be adhesive, and there is a distinct odour of lime-cream. This dust, you will observe, is not the gritty, grey dust of the street but the fluffy brown dust of the house, showing that it has been hung up indoors most of the time, while the marks of moisture upon the inside are proof positive that the wearer perspired very freely, and could therefore, hardly be in the best of training.”
注释摘要
华生被福尔摩斯关于帽子主人经济状况下滑的推理说服，但仍然觉得“先见之明”与“道德退化”这两个判断过于玄虚，于是直言发问。福尔摩斯当即给出了逐条的逻辑说明，这一段正是整场帽子推演中最能体现他演绎法特色的一节。 福尔摩斯首先指向帽子上残留的“帽带扣”——那个位于帽檐内侧的小圆片和绳环。他解释说，这类防风扣从来不作为帽子的标准配件出售；帽匠做帽子时，并不会主动加…