“And yet you seem to have repudiated all processes of deduction whereby the truth may be arrived at. Have you, by any chance, entirely renounced your faith in the operations of the human mind?”
“Ah, there speaks the voice of God’s great common people!” exclaimed Vance. “Your mind is so typical, Markham. It works on the principle that what you don’t know isn’t knowledge, and that, since you don’t understand a thing, there is no explanation. A comfortable point of view. It relieves one from all care and uncertainty. Don’t you find the world a very sweet and wonderful place?”
Markham adopted an attitude of affable forbearance.
“You spoke at lunch time, I believe, of one infallible method of detecting crime. Would you care to divulge this profound and priceless secret to a mere district attorney?”
Vance bowed with exaggerated courtesy.[10]
“Delighted, I’m sure,” he returned. “I referred to the science of individual character and the psychology of human nature. We all do things, d’ ye see, in a certain individual way, according to our temp’raments. Every human act—no matter how large or how small—is a direct expression of a man’s personality, and bears the inev’table impress of his nature. Thus, a musician, by looking at a sheet of music, is able to tell at once whether it was composed, for example, by Beethoven, or Schubert, or Debussy, or Chopin. And an artist, by looking at a canvas, knows immediately whether it is a Corot, a Harpignies, a Rembrandt, or a Franz Hals. And just as no two faces are exactly alike, so no two natures are exactly alike: the combination of ingredients which go to make up our personalities, varies in each individual. That is why, when twenty artists, let us say, sit down to paint the same subject, each one conceives and executes it in a different manner. The result in each case is a distinct and unmistakable expression of the personality of the painter who did it. . . . It’s really rather simple, don’t y’ know.”
“Your theory, doubtless, would be comprehensible to an artist,” said Markham, in a tone of indulgent irony. “But its metaphysical refinements are, I admit, considerably beyond the grasp of a vulgar worldling like myself.”
“ ‘The mind inclined to what is false rejects the nobler course,’ ” murmured Vance, with a sigh.
“There is,” argued Markham, “a slight difference between art and crime.”
“Psychologically, old chap, there’s none,” Vance amended evenly. “Crimes possess all the basic factors of a work of art—approach, conception, technique, imagination, attack, method, and organization. Moreover, crimes vary fully as much in their manner, their aspects, and their general nature, as do works of art. Indeed, a carefully planned crime is just as direct an expression of the individual as is a painting, for instance. And therein lies the one great possibility of detection. Just as an expert æsthetician can analyze a picture and tell you who painted it, or the personality and temp’rament of the person who painted it, so can the expert psychologist analyze a crime and tell you who committed it—that is, if he happens to be acquainted with the person—, or else can describe to you, with almost mathematical surety, the criminal’s nature and character. . . . And that, my dear Markham, is the only sure and inev’table means of determining human guilt. All others are mere guess-work, unscientific, uncertain, and—perilous.”