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Bharatiya Sakshya Adhiniyam, 2023 — Section 40: Facts bearing upon opinions of experts

§ SECTION 40 · BSA 2023 · CHAPTER II — RELEVANCY OF FACTS

Facts bearing upon the opinions of experts

Once an expert opinion is relevant (§ 39), the facts that support or contradict it become relevant too — even if, on their own, they would be beside the point.

How to read Section 40

Facts that test the expert — both ways.

The facts

Facts that would be irrelevant on their own.

Become relevant

If they support or are inconsistent with an expert’s opinion.

The condition

Only when that expert opinion is itself relevant (§ 39).

The bare Act

The section in its own words — colour-keyed by what each phrase does.

Section 40 · verbatim

Facts, not otherwise relevant, are relevant if they support or are inconsistent with the opinions of experts, when such opinions are relevant.

Illustrations

(a) The question is, whether A was poisoned by a certain poison. The fact that other persons, who were poisoned by that poison, exhibited certain symptoms which experts affirm or deny to be the symptoms of that poison, is relevant.

(b) The question is, whether an obstruction to a harbour is caused by a certain sea-wall. The fact that other harbours similarly situated in other respects, but where there were no such sea-walls, began to be obstructed at about the same time, is relevant.

In short: an expert opinion never stands alone — the Court also wants the facts that test it. So facts that would be pointless by themselves become relevant when they confirm or undermine a relevant expert opinion. The rule is even-handed: it lets in the facts against the expert just as much as those for him.

→ This carries forward IEA 1872 § 46 — the companion to the expert-opinion rule in § 39.

Glossary

not otherwise relevant

A fact with no independent relevance — it enters only through this section.

support

To confirm or corroborate the expert’s opinion.

inconsistent with

To contradict or undermine the expert’s opinion — equally relevant.

opinions of experts

The opinions made relevant by § 39 — this section rides on them.

when such opinions are relevant

The gate — if there is no relevant expert opinion, this section does nothing.

bears on

To have a logical connection to the truth or falsity of the expert’s opinion.

The picture

Facts that back or break the expert — both come in.

EXPERT OPINIONrelevant under § 39a fact that SUPPORTS it✓ relevanta fact INCONSISTENT with it✗ equally relevantboth are RELEVANTotherwise-irrelevant facts come in — but only while a relevant expert opinion stands

The section, part by part

Tap a part — the picture-story tells it first; the word-by-word text and example follow.

the ruleFacts that test the expert come in too

In one lineA fact that would otherwise be irrelevant becomes relevant if it supports or contradicts a relevant expert opinion.
1An expert opinionrelevant under§ 392A fact tests itit supports — orcontradicts the expert3→ that fact is inthough otherwiseirrelevant, it comes inonce § 39 opens the door, the facts that test the expert — for or against — come in too
Facts, not otherwise relevant,facts that alone would not countfacts that, on their own, would be irrelevant…
are relevant if they support or are inconsistent with the opinions of experts,support OR contradict the expert…become relevant if they back up or clash with an expert’s opinion…
when such opinions are relevant.⚠ only if the opinion is relevant…but only when that expert opinion is itself relevant (under § 39).
ExampleAn expert says poison X produces symptoms S. The fact that other people poisoned by X did (or did not) show S is relevant — it supports or undercuts the expert, though on its own it would be beside the point.
✗ Not thisThe fact must bear on a relevant expert opinion — no expert opinion in play, no bootstrapping. And it cuts both ways: facts that contradict the expert are just as relevant as those that support — this is not a one-sided prop for the expert.

the illustrationsPoison symptoms, and the sea-wall

In one line(a) other poison victims’ symptoms confirm or deny the expert; (b) other wall-less harbours show whether the sea-wall really caused the obstruction.
others poisoned by the same poisonsymptoms S?the expert comparessymptoms match → supports ✓no match → contradicts ✗Illustration (a): whether other victims of the poison showed the same symptoms — supports or denies the expert.
harbour WITH sea-wallobstructed (silted up)other harbours, NO wallALSO obstructed, same timeso — was it really the wall?Illustration (b): wall-less harbours obstructed at the same time — relevant to whether the sea-wall caused it.
(a) other persons poisoned by that poison showed symptoms which experts affirm or deny to be its symptomspoison symptomsmatching (or mismatching) symptoms support or deny the expert.
(b) other similarly-situated harbours, but with no sea-wall, began to be obstructed at about the same timethe sea-wall testif wall-less harbours silted up too, that bears on whether the wall was the cause.
Example(b): the expert blames the new sea-wall for silting the harbour. That other harbours with no wall silted up at the same time is relevant — it tends to contradict that the wall was the cause.
✗ Not thisThese facts (other victims, other harbours) would be irrelevant on their own — they come in only because they test a relevant expert opinion. Remove the expert opinion and they drop out.

Connected provisions

§ 39

Opinions of experts

§ 40 rides on § 39 — it works only where an expert opinion is already relevant.

§ 9

Facts not otherwise relevant

The same idea — a fact irrelevant in itself becomes relevant by its bearing on a fact in issue.

§ 41 · next

Opinion on handwriting & signature

The next opinion-relevancy provision in Chapter II.

lineage

IEA 1872, § 46

Carried forward — the companion to the expert-opinion rule.