There are, however, cases in which the Court is not in a position to form a correct judgment, without the help of the persons who have acquired special skill or experience in a particular subject.
In such cases, the help of experts is required. In these cases, the rule is relaxed, and expert evidence is admitted to enable the Court to come to a proper decision and under this head come matters of science, art, trade, handwriting, finger impressions and foreign law. The rule admitting expert evidence is founded on necessity.
Who is an expert? The expression “expert” covers ‘person specially skilled’. An expert may be defined as a person who, by practice and observation, has become experienced in any science or trade. He is one who has devoted time and study to a special branch of learning, and is thus specially skilled in that field wherein he is called to give his opinion.
The term implies both superior knowledge and practical experience in the art or profession, but generally, nothing more is required to entitle one to give testimony as an expert than that he had been educated in a particular art or profession. Before such evidence can be considered, it must be proved that the person giving the evidence is an expert. If on considering the evidence, the Court comes to the conclusion that the person who has given evidence is not an expert; his opinion has to be discarded. How an Expert’s Testimony differs from that of an Ordinary Witness: (1) An expert’s evidence is not confined to what actually took place, but covers his opinions on facts, e.g., although a doctor may not have attended the victim, he can still give his opinion as to the cause of the victim’s death or the effect of a certain poison. (2) An expert can refer to and rely upon experiments conducted by him in the absence of the other party. Thus, on a charge of arson, evidence of an experiment conducted by an expert subsequent to the fire is admissible to show how the fire may have originated.
(3) An expert may quote passages from well-known text books on the subject and may refer to them to refresh his memory. (4) An expert may state facts relating to other cases in pari materia similar to the case under investigation. The Value of Expert Evidence: Perhaps the testimony which least deserves credit with a jury is that of skilled witnesses. These witnesses are usually required to speak not facts, but to give opinions; and when this is the case, it is often quite surprising to see with what facility, and to what extent, their views can be made to correspond with the wishes or the interests of the parties who call them.
They do not indeed wilfully misrepresent what they think, but their judgment becomes so warped by regarding the subject from one point of view, that even when conscientiously disposed, they are incapable of forming an independent opinion. Testimony of experts is usually considered to be of slight value, since they are proverbially, though perhaps unwittingly, biased in favour of the side which calls them. As the Privy Council once observed: “There cannot be any more unsatisfactory evidence than that of an interested party called as an expert.” In Kishore Chandra Singh Deo v. Babu Ganesh Prasad Bhagat, (A.
I.R. 1954 S.C. 316), the Supreme Court observed that the conclusions based on mere comparison of handwriting must, at best, be indecisive, and therefore, should yield to the positive evidence in the case. Similarly, in Emperor, v. Ramrao Mangesh, it was held that expert evidence, as a mode of proof, though permissible, is hazardous and inconclusive, and as a method of proving disputed handwriting, it is accepted by the Courts with great caution. It is indeed unsafe to base a conviction on the uncorroborated opinion of a handwriting expert.
As observed in an American case (Peoples v. Patrick, 182 N.Y. 131),— “Expert witnesses are affected by that pride of opinion and that kind of mental fascination with which men are affected when engaged in the pursuit of what they call scientific enquiries.” As remarked by Pope in his “Essay on Criticism”.— “Of all the causes which conspire to blind, Man’s erring judgment and misguide the mind, What the weak head with strongest bias rules, Is pride, the never-failing vice of fools.”