EXPERT TESTIMONY. 653 



EXPERT TESTIMONY. 



By Professoe FRANK W. CLAEKE. 



OF all the causes whicli tend to discredit science, not one is 

 more mischievous than the policy of the courts with regard 

 to " expert testimony." Whenever a question of scientific fact or 

 theory becomes involved in the settlement of a lawsuit, a swarm of 

 " professional " witnesses are called, who testify on opposites sides, 

 until neither judge nor jury can tell what is or is not really settled. 

 Of these witnesses some are trained, some untrained ; some are 

 competent, some incompetent ; some are scrupulous, others are 

 unprincipled ; and no sure rule of discrimination is properly ap- 

 plied between them. As a rule, all, though sworn, are expected 

 to act like paid attorneys, each serving the side which employs 

 him ; and the one supreme test of capacity is that of shrewdness 

 under cross-examination. Strange perversions of science thus 

 get before the courts, to receive equal weight with worthy evi- 

 dence ; doubts are raised or exaggerated, and facts are misstated 

 or suppressed. The highest scientific authorities, the men whose 

 researches create science, are therefore averse to testifying, and 

 rarely appear in the witness-box ; for they can not risk their repu- 

 tations upon one-sided or partisan statements, nor do they like the 

 misrepresentations into which their evidence may be unscrupu- 

 lously distorted. Under the present usage the expert bears wit- 

 ness for one side against the other ; whereas the truth, being " nei- 

 ther black nor white, but gray," may stand in the middle of the dis- 

 puted territory. The science of the court-room is litigious, not ju- 

 dicial ; and no place is found for the unbiased presentation of fact, 

 regardless of its bearing upon the personal interests at stake, and 

 with fair credit given to genuine doubts and uncertainties. To 

 the scientific partisan the com't-room doors are wide open ; to the 

 scientific jurist they are practically closed, for no one wants his 

 services. In criminal cases, perhaps, a better showing may be 

 made ; for here we have an impersonal state seeking to do exact 

 justice, and its experts have no private ends to gratify. If, how- 

 ever, they are incompetent, the criminal, perhaps a poisoner, may 

 escape punishment ; and glaring cases of this kind are on record. 

 Any experienced chemist can easily cite examples in point, for 

 prosecuting attorneys are not always able to distinguish between 

 true and false experts, and the latter sometimes destroy the evi- 

 dence of crime in their blundering efforts to detect it. 



Most men of science, and indeed most professional men, have 

 two reputations — the one within, the other without the ranks of 

 their colaborers. The two are rarely, if ever, quite commensur- 



