The proof lies upon him who affirms, not upon him who denies. The common law rule of evidence is that the burden of proof lies on the party who assert the affirmative of the issue or question in dispute. [Ram Chandra Shau v. Madhab Nayek, 1953 C 484; Bankey Behari Lal v. Lala Babu, 1955 A 1 (FB); Sobha Singh v. Behari Lal Beni Parsad, 1956 PLR 432; Mohammad Shah v. Vasih-ud-din Ansari, 1956 SC 713].
The rule is based on the maxim ei incumbit, qua dicit, non qui negat (the burden of proof is on the party who asserts, not on his who denies). The reason of the rule is, firstly, that it is but just that he who invokes the aid of the law should be the first to prove his case; and, secondly that a negative is more difficult to establish than an affirmative. [Phipson, Ev., 7th Ed., p. 30].
In deciding which party asserts the affirmative. Regard must be had to the substance of the issue and not merely to its grammatical form, which latter the pleader can frequently vary at will [Soward v. Leggatt, 7 C & P 615]; moreover, a negative allegation must not be confound with the mere traverse of an affirmative have been introduced into this subject by some unfortunate language in which the above principle has been enunciated. [Best, p. 270].