SCIENCE 



[Vol. XX. No. 492 



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ON THE UNCEETAINTT OF CONCLUSIONS.^ 



BY T. C. MENDENHAI,L. 



About seven years ago, on the morning of a cold day in 

 winter, a rough-looking, scantily-dressed man was observed 

 to leave a freight car, which was standing upon a side-track 

 near a small country town, and make his way rapidly into 

 the fields and woods beyond. 



From his appearance it was evident that he belonged to 

 that vast army of tramps which is never in need of mobiliza- 

 tion and which carries upon its muster-rolls many who 

 possess most of the virtues of the good and none of the 

 vices of the bad, having lost only the power of further re- 

 sistance against continued antagonism and unfriendly en- 

 vironment. 



The behavior of this man excited no comment, and his 

 existence was remembered a few hours later only because of 

 the discovery of the body of a stranger, who had evidently 

 been murdered, on the floor of the car which he had been 

 seen to leave. Pursuit followed immediately, and capture 

 within a day or two. One or two clever detectives interested 

 themselves in finding evidence of his guilt, and within a few 

 days had prepared a case which lacked little in the detail of 

 its elaboration or in its artistic finish. 



It was proved that two strangers were seen in the suburbs 

 of the town at a late hour on the previous night, although 

 they were not together. The prisoner was identified beyond 

 doubt as the man who hastily left the car in the morning. 

 The murderer had left no means of identiBcation except a 

 small piece of muslin, evidently torn from the sleeve of his 

 shirt, and which was stained with the blood of his victim. 

 On the arrest of the prisoner one or two blood stains were 

 found upon his clothiog, and, what was more convincing 

 than all else, the bit of sleeve found in the car fitted exactly 

 into the place in his own garment, from which it must have 

 been torn in the struggle which preceded the crime. 



> Address as retiring president, delivered Jan. 20, 1892, before the Philoso- 

 phical Society of Washington. 



While all of this evidence might be classified as " circum- 

 stantial," it was so complete and satisfactory that no jury 

 could be expected to entertain serious doubt as to the guilt 

 of the prisoner, and, in spite of his protestations of inno- 

 cence, a sentence to life imprisonment was in accord with 

 the judgment of the general public. 



Only a few weeks since this man was set free and declared 

 to be innocent of the crime for which he had already served 

 seven years at bard labor, the misleading character of the 

 evidence on which he was convicted having been exposed 

 through the voluntary confession of the real criminal. The 

 facts thus brought out were, briefly, as follows : — 



There were three men in the case. The first, who was . 

 afterward murdered, slept upon the floor of the car when 

 the second, the real murderer, entered it. In the dark he 

 stumbled over the sleeping man, who awoke and immediately 

 attacked him. The quarrel did not last long, the original 

 occupant being left dead upon the floor of the car while the 

 murderer quickly made his escape, leaving the village and 

 neighborhood behind him as far and as fast as possible. An 

 hour or two later the third man, seeking shelter and sleep, 

 finds his way into the car, and dropping on the floor, is soon 

 in a deep slumber. He awakes at break of day to find that 

 a dead man has been his companion, and to see that his own 

 sleeve is smeared with the blood of the victim. Alarmed 

 by this discovery, and realizing in some degree the perilous 

 position in which he is thus placed, he tears off the stained 

 portion of his garment, and, hastily leaving the car, he flees 

 from the scene as rapidly as possible. 



Nothing can be more simple or more satisfactory than this 

 account of the affair, and yet nothing is more natural than 

 that he should be accused of the crime and brought to trial. 

 The evidence against him was convincing, and it was all abso- 

 lutely true. It was not strange, therefore, that his conviction 

 and imprisonment should follow. 



It will doubtless appear to many that the foregoing is too 

 closely allied to the sensational to serve fitly as an introduc- 

 tion to an address prepared for a society of philosophers, and 

 I am ready to acknowledge the apparen t validity of the crit- 

 icism. I am led to its selection, however, because it is an 

 account of an actual occurrence, which illustrates in a man- 

 ner not to be misunderstood a not unrecognized proposition 

 to a brief exposition and partial development of which I ask 

 your attention this evening. This proposition is that, in the 

 treatment of many questions with which we are confronted 

 in this world, our premises may be absolutely true and our 

 logical processes apparently unassailable and yet our conclu- 

 sions very much in error. 



No department of human knowledge or region of mental 

 activity will fail to yield ample illustration and proof of this 

 proposition. An astonishingly large number of debatable 

 questions present themselves to the human intellect. Many 

 of them are conceded to be of such a nature that differences 

 of opinion concerning them must continue, perhaps, indefi- 

 nitely. 



But there is a very large and a very important class of 

 problems, the solution of which is apparently not impossible 

 and often seemingly easy, regarding which the most diverse 

 views are most persistently held by persons not difl'ering 

 greatly in intelligence or intellectual training. 



Men whose business it is to weigh evidence and to reach cor- 

 rect conclusions, in spite of inadequacy of information and 

 perversion of logic, constitute no exception to this statement, 

 but, on the contrary, furnish many of its most notable illus- 

 trations. 



