The Evidence Act
66 The primary Judge in the present case had the advantage of observing the key witnesses, specifically Neil, Sandra and Carolyn. He clearly preferred the evidence of Carolyn when it was in conflict with that of Neil and Sandra, although he did not accept Carolyn’s evidence on some issues. But much of his Honour’s reasoning was founded on what he regarded as the inherent improbability of the account given by Neil and Sandra and the inconsistencies in their evidence. This led him to reject Neil and Sandra’s account, not only when it was in conflict with Carolyn’s evidence but even when it was uncontradicted by the evidence of any other witness. In addition, his Honour took into account his preference for the expert opinion of Mr Anderson over that expressed by Mr Dubadet.
67 The findings made by the primary Judge attributed very serious wrongdoing to Neil and Sandra. Although his Honour said in the Primary Judgment that it was unnecessary to find that there was a forgery or who was responsible for the forgery, he found that Neil knowingly propounded a document he knew had not been signed by Lyall. In the Second Judgment, his Honour expressly found (at ) that the case was one of “proven misconduct” by Neil as the nominated executor. The distinction between a finding that Neil forged Lyall’s signature and a finding that he knowingly propounded the forged Second Codicil is a very fine one so far as Neil’s culpability is concerned.
68 This is a case which calls for careful consideration of s 140(2)(c) of the Evidence Act 1995 (NSW). Section 140 provides as follows:
“Civil proceedings: standard of proof
(1) In a civil proceeding, the court must find the case of a party proved if it is satisfied that the case has been proved on the balance of probabilities.
(2) Without limiting the matters that the court may take into account in deciding whether it is so satisfied, it is to take into account:
(a) the nature of the cause of action or defence, and
(b) the nature of the subject-matter of the proceeding, and
(c) the gravity of the matters alleged.”
69 Section 140(2)(c) is generally regarded as giving effect to the principles stated by Dixon J in Briginshaw v Briginshaw  HCA 34; 60 CLR 336. In that case, Dixon J rejected (at 361) the suggestion that the common law developed a third standard of persuasion, other than proof on the balance of probabilities and proof beyond reasonable doubt. He went on to say (at 362) that in a civil case:
“… it is enough that the affirmative of an allegation is made out to the reasonable satisfaction of the tribunal. But reasonable satisfaction is not a state of mind that is attained or established independently of the nature and consequence of the fact or facts to be proved. The seriousness of an allegation made, the inherent unlikelihood of an occurrence of a given description, or the gravity of the consequences flowing from a particular finding are considerations which must affect the answer to the question whether the issue has been proved to the reasonable satisfaction of the tribunal. In such matters ‘reasonable satisfaction’ should not be produced by inexact proofs, indefinite testimony, or indirect inferences.”
70 Later cases have made it clear that observations such as that made by Dixon J are not to be understood as directed to the standard of proof in a civil case which, subject to statute, requires proof on the balance of probabilities. Rather, the observations should be understood as:
“…merely reflecting a conventional perception that members of our society do not ordinarily engage in fraudulent or criminal conduct and a judicial approach that a court should not lightly make a finding that, on the balance of probabilities, a party to civil litigation has been guilty of such conduct.”
Neat Holdings Pty Ltd v Karajan Holdings Pty Ltd  HCA 66; 67 ALJR 170 at  (Mason CJ, Brennan, Deane and Gaudron JJ). (Citations omitted.)
71 The primary Judge correctly stated (at ) that Neil bore the onus of proving on the balance of probabilities that the Second Codicil had been executed by Lyall in conformity with s 6 of the Succession Act 2006 (NSW). His Honour also correctly stated that the burden continued throughout the case and that Carolyn did not bear an onus of proving that in the circumstances of this case the Second Codicil was a forgery. But Neil was placed in a position where, in order to prove that the Second Codicil was authentic, he had to rebut the allegation that Lyall had never signed the document and that Neil had either forged Lyall’s signature or been compliant in propounding a forgery.
72 It has been held in New South Wales that the seriousness of an allegation of this kind should be taken into account by the trier of fact in determining whether the proponent of the document has made out his or her case on the balance of probabilities. That is so even though the proponent bears the onus of establishing the authenticity of the document on the balance of probabilities: Gawne v Gawne  2 NSWLR 449 at 454 (Glass JA, Reynolds JA agreeing). In the present case, the primary Judge did not advert to the seriousness of the allegations made against Neil and Sandra or, in the words of Dixon J, the “inherent unlikelihood” that Neil would have forged the Second Codicil or knowingly propounded a forgery.
73 The language of s 140 of the Evidence Act is consistent with the approach taken in Gawne v Gawne. Section 140(2) says that in deciding whether the court is satisfied that the case of a party is proved on the balance of probabilities, it is to take into account both the nature of the defence and the gravity of the matters alleged. The sub-section does not say that the court is only to take into account the gravity of the matters alleged by the party bearing the onus of proving a case on the balance of probabilities. If the defence alleges, for example, that the proponent of a will has forged the testator’s signature, s 140(2) requires the court to take into account the gravity of the allegation made in the defence when deciding whether the proponent has proved his or her case on the balance of probabilities.
74 The need to take into account the gravity of the allegation made against Neil is significant in the present case because the primary Judge placed considerable weight on the “inherent” oddities (at ) in the evidence given by Neil and Sandra, even on matters in respect of which there was no contradictory evidence. I shall return to some of those matters, but mention should first be made of matters to which his Honour did not refer, but which bear on the inherent probability that the Second Codicil was forged and thus on whether Neil proved on the balance of probabilities that the Second Codicil was authentic.