SHERLOCK HOLMES’ SCIENCE OF DEDUCTION AND ANALYSIS
Note: Nos. 1-60 are from the Doyle complete canon; 61-94 are from the Basil Rathbone movies, and 95-97 are from the Young Sherlock Holmes movie.
1. Like all other arts, the Science of Deduction and Analysis is one which can only be acquired by long and patient study, nor is life long enough to allow any mortal to attain the highest possible perfection in it. Before turning to those moral and mental aspects of the matter which present the greatest difficulties, let the inquirer begin by mastering more elementary problems. Let him on meeting a fellow-mortal, learn at a glance to distinguish the history of the man and the trade or profession to which he belongs. Puerile as such an exercise may seem, it sharpens the faculties of observation, and teaches one where to look and what to look for. By a man’s finger-nails, by his coat-sleeve, by his boot, by his trouser-knees, by the callosities of his forefinger and thumb, by his expression, by his shirt-cuffs – by each of these things a man’s calling is plainly revealed. That all united should fail to enlighten the competent inquirer in any case is almost inconceivable. 2. You should consider your brain originally is like a little empty attic, and you have to stock it with furniture as you choose. A fool takes in all lumber of every sort that he comes across, so that the knowledge which might be useful to him gets crowded out, or at best is jumbled up with a lot of other things, so that he has difficulty in laying his hands upon it. Now the skilled workman is very careful indeed as to what he takes into his brain attic. He will have nothing but the tools which may help him in doing his work, but of these he has a large assortment and all in the most perfect order. It is a mistake to think that that a little room has elastic walls and can distend to any extent. Depend upon it there comes a time when for every addition of knowledge you forgot something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones. 3. An observant man can learn by an accurate and systematic examination of all that came in his way. From a drop of water, a logician could infer the possibility of an Atlantic or a Niagara without having seen or heard of one or the other. So all life is a great chain, the nature of which is known whenever we are shown a single link of it. 4. Always approach a case with an absolutely blank mind, which is always an advantage. Form no theories, just simply observe and draw inferences from your observations. 5. It is a capital mistake to theorize before you have all the evidence. Insensibly, one begins to twist the facts to suit theories, instead of theories to suit facts. It biases the judgment. 6. The temptation to form premature theories upon insufficient data is the bane of this profession. 7. They say that genius is an infinite capacity for taking pains. It’s a very bad definition, but it does apply to detective work. 8. The height of a man, in nine cases out of ten, can be told from the length of his stride. 9. When a man writes on a wall, his instinct leads him to write above the level of his own eyes. 10. To a great mind, nothing is little.
11. It is a mistake to confound strangeness with mystery. The most commonplace crime is...