Modern trials cannot be won with witnesses of fact alone. Cases turn increasingly on scientific analyses, digital forensics, medical diagnoses, engineering opinions, and specialised domains that did not exist when the Indian Evidence Act, 1872 was drafted. Section 39 of the Bharatiya Sakshya Adhiniyam, 2023 (BSA) recognises that reality with a single, consequential drafting move: it extends expert opinion beyond "foreign law, science, or art" to those subjects or any other field. It is one of the most significant substantive changes the BSA has made in Chapter II.
39. Opinions of experts. (1) When the Court has to form an opinion upon a point of foreign law or of science or art, or any other field, or as to identity of handwriting or finger impressions, the opinions upon that point of persons specially skilled in such foreign law, science or art, or any other field, or in questions as to identity of handwriting or finger impressions are relevant facts and such persons are called experts.
Illustrations.
(a) The question is, whether the death of A was caused by poison. The opinions of experts as to the symptoms produced by the poison by which A is supposed to have died, are relevant.
(b) The question is, whether A, at the time of doing a certain act, was, by reason of unsoundness of mind, incapable of knowing the nature of the act, or that he was doing what was either wrong or contrary to law. The opinions of experts upon the question whether the symptoms exhibited by A commonly show unsoundness of mind, and whether such unsoundness of mind usually renders persons incapable of knowing the nature of the acts which they do, or of knowing that what they do is either wrong or contrary to law, are relevant.
(c) The question is, whether a certain document was written by A. Another document is produced which is proved or admitted to have been written by A. The opinions of experts on the question whether the two documents were written by the same person or by different persons, are relevant.
(2) When in a proceeding, the court has to form an opinion on any matter relating to any information transmitted or stored in any computer resource or any other electronic or digital form, the opinion of the Examiner of Electronic Evidence referred to in section 79A of the Information Technology Act, 2000, is a relevant fact.
Explanation.—For the purposes of this sub-section, an Examiner of Electronic Evidence shall be an expert.
Two consolidated provisions, one significant expansion
Section 39 corresponds to two provisions in the Indian Evidence Act, 1872 — Section 45 (opinions of experts) and Section 45A (opinion of Examiner of Electronic Evidence). The BSA has done two things at once. It has merged Section 45A IEA into Section 39 as sub-section (2), so a litigant no longer has to navigate two separate provisions to find both the general and the electronic-evidence expert rules. And it has expanded the substantive scope of sub-section (1) by adding the words "or any other field" in two places — first among the subjects on which the court has to form an opinion, and again in describing the persons "specially skilled" in those subjects.
| Feature | Sections 45 and 45A, IEA | Section 39, BSA |
|---|---|---|
| Subjects for expert opinion | Foreign law, science, art, identity of handwriting or finger impressions | Same list plus "or any other field" |
| Structure | Two separate sections (45 and 45A) | One section with sub-sections (1) and (2), plus Explanation |
| Electronic-evidence expert | Examiner of Electronic Evidence, Section 45A IEA | Same expert, now Section 39(2), with an Explanation confirming their status as an expert |
What "or any other field" changes in practice
Under the 1872 Act, courts periodically had to strain to fit new specialisations into the four categories of foreign law, science, art, and handwriting or finger impressions. Modern disciplines — cybersecurity, cryptocurrency valuation, digital forensics beyond the Examiner-of-Electronic-Evidence framework, corporate finance, environmental impact, structural engineering, insurance underwriting, and specialised medical sub-fields — did not sit neatly within any of them. Judges usually found a way, treating unfamiliar disciplines as species of "science" or "art", but the label had a strained quality.
Section 39's addition of "or any other field" removes the strain. The court may take expert opinion on any field where specialised skill is genuinely required, without having to pretend that the field is a form of science or art. This is not a licence for every specialist to give opinion evidence; the underlying test — that the witness be "specially skilled" in the field, on a point the court has to form an opinion about — remains. What has changed is the range of fields to which that test may be applied.
Sub-section (2): the Examiner of Electronic Evidence
Sub-section (2) admits the opinion of the Examiner of Electronic Evidence — an officer notified under Section 79A of the Information Technology Act, 2000 — on any matter relating to information transmitted or stored in any computer resource or any other electronic or digital form. The Explanation confirms, for the avoidance of doubt, that such an Examiner is an "expert." This matters because Section 45 of the BSA, which admits the grounds of an opinion, and Section 40, which admits facts bearing on an expert opinion, both hinge on the witness being an expert. Sub-section (2) with its Explanation puts the Examiner of Electronic Evidence squarely within that framework.
The Delhi High Court in State v. Mohd. Afzal & Ors., Crl App 80/2003 (decided 29 October 2003), treated the electronic-evidence framework of Sections 45A, 65A and 65B IEA as a coherent unit, admitting computer printouts and CDs on the strength of the statutory scheme. That reasoning survives the recodification because the underlying statutory architecture has been preserved — the Examiner is now under Section 39(2) BSA, and the electronic-record certificate under Section 63 BSA.
Three illustrations covering the classic reach
The illustrations reflect the traditional core cases the section has always served — poisoning, insanity, and disputed handwriting. They remain fully applicable and are supplemented, not displaced, by the widened scope in sub-section (1). In each illustration, an expert opinion on a point beyond the ordinary knowledge of the court becomes relevant on the fact in issue.
Working with the rest of the opinion cluster
Section 39 is the foundation of the cluster running through Sections 39 to 45. Section 40 admits otherwise-irrelevant facts that bear on an expert opinion. Section 41 admits lay opinion on handwriting and signature. Sections 42, 43 and 44 admit specific opinions on general customs, community usages, and relationship. Section 45 makes the grounds of any relevant opinion admissible. Section 39's expansion "or any other field" enlarges the set of expert opinions that trigger Sections 40 and 45 — silently but importantly, the reach of those companion provisions has grown with it.
Key Takeaways
- Consolidation: Sections 45 and 45A IEA are now sub-sections (1) and (2) of Section 39 BSA.
- Scope expanded: "or any other field" is added, widening expert evidence beyond the traditional four categories.
- Test unchanged: the witness must be specially skilled in the subject and the point must be one on which the court needs their opinion.
- Examiner of Electronic Evidence confirmed as expert: the Explanation to sub-section (2) settles the point for Sections 40 and 45.
- Court retains control: per Ramesh Chandra Agrawal, expert opinion is to be weighed, not deferred to.
Conclusion
Section 39 is the BSA at its most forward-looking. By adding "or any other field," it acknowledges that the domains in which specialised knowledge assists a court are no longer confined to foreign law, science, art, and handwriting. By folding the Examiner of Electronic Evidence into sub-section (2) and confirming their expert status, it aligns the digital-evidence expert with the general expert framework. Together, these changes prepare Indian evidence law for a courtroom in which cases increasingly turn on knowledge that neither judge nor jury nor party can be expected to possess — while keeping intact the fundamental discipline that experts assist the court, and do not replace it.