Section 47 of Evidence Act "Facts bearing upon opinions of experts"
Facts, not otherwise relevant, are relevant if they support or are inconsistent with the opinions of experts, when such opinions are relevant.
Section 47 of Evidence Act "Opinion as to handwriting, when relevant"
When the Court has to form an opinion as to the person by
whom any document was written or signed, the opinion of any
person acquainted with the handwriting of the person by whom
it is supposed to be written or signed that it was or was
not written or signed by that person, is a relevant fact.
Illustration
The question is, whether a given letter is in the
handwriting of A, merchant in London.
B is a merchant in Calcutta, who has written letters
addressed to A and received letters purporting to be written
by him. C is B's clerk, whose duty it was to examine and
file B's correspondence. D is B's broker, to whom B
habitually submitted the letters purporting to be written by
A for the purpose of advising with him thereon.
The opinions of B, C and D on the question whether the
letter is in the handwriting of A are relevant, though
neither B, C and D ever saw A write.
Section 47a of Evidence Act "Opinion as to digital signature where relevant"
When the Court has to form an opinion as to the digital signature or any person, the opinion of the Certifying Authority which has issued the Digital Signature Certificate is a relevant fact.