Section 101 is based on the rule, i.e., incumbit probation qui decit non negat which means the burden of proving a fact rests on the party who substantially asserts the affirmative of the issue and not upon the party who denies it. This rule is derived from Roman law, and is supportable not only upon the ground of fairness, but also upon that of the greator practicaldifficulty which is involved in proving a negative than in proving an affirmative. Section 101 of the Act is reflective of the general principle that a party who asserts the affirmative of an issue, the burden of proof lies on him to prove that fact. The burden of proving a case remains throughout the entire case on the party on whom the pleadings originally place it. It never shifts; the party, whether, plaintiff or defendant, who substantially asserts the affirmative of the issue has this burden of proof.
In a popular sense it is also known as evidentiary burden or onus of proof burden of evidence. It may shift from side to side during the progress of trial. It must be noted that at the beginning of the trial/proceeding, the burden of proof and the unit of poof as to any particular issue are generally on the same party. The party is supposed to lead evidence bearing upon the relevant facts and facts-in-issue and show a prima facie case. Once the prima facie case is established, the burden of evidence is shifted to the adurs party. The adverse party may by production of evidence destroying the prima facie case against him, satisfy the burden and restore it to the original party.
While Section 101 lays down that whoever wants to win must pro, Section 102 lays down the
rule whoever would lose must prove. Section 107 of the Act lays down the principle that the burden of proof lies on the person who would fail if no evidence were given on either side. So, for instance, at the beginning of the case in the plaintiff does not adduce any evidence then he would lose the case, similarly, once the plaintiff prima facie establishes his case, if the defendant does not adduce any eviderise to the contrary, he would lose the case. Therefore, the burden to disprove the case of the plaintiff at that point of time would lie upon the defendant. Initially, at the beginning of the case, the burden of proof under Section 101 and the onus or the burden to disproveunder Section 102 of the Act always lies upon the person bringing the case.
The best tests for ascertaining on whom the burden of proof lies, are, to consider first, which CA party would succed if no evidence were given on either side and secondly, what would be the effect of striking out of the record the allegation to be proved. The onus lies on the party that would fail, if either of these steps were pursued.
Section 103 shows that whoever asserts a particular fact, in whatever form it may be (positive, negative affirmative or denying), must prove it unless there is a rule of law either in the Evidence Act or in some other statute that the burden in that particular case lies upon the other party. For instance, in a case of malicious prosecution, the plaintiff has the burden to prove the factum that the defendant prosecuted him without any just and reasonable cause, though it is a fact in negative form.
The difference between Section 101 and Section 103 of the Act is that in case of Section 101 the entire case has to be proved, whereas, in case of Section 103 a particular fact has to be only proved. For instance, the prosecution proves its case against the accused, then the accused takes the defence of alibi. Then in this case it would be a particular fact, and the burden to disprove the same would lie upon the accused.