ON 4 APRIL 1952, the High Court of Australia delivered Luxton v Vines  HCA 19; (1952) 85 CLR 352 (4 April 1952).
“In questions of this sort, where direct proof is not available, it is enough if the circumstances appearing in evidence give rise to a reasonable and definite inference: they must do more than give rise to conflicting inferences of equal degrees of probability so that the choice between them is mere matter of conjecture: see per Lord Robson, Richard Evans & Co. Ltd. v. Astley (1911) AC 674, at p 687. But if circumstances are proved in which it is reasonable to find a balance of probabilities in favour of the conclusion sought then, though the conclusion may fall short of certainty, it is not to be regarded as a mere conjecture or surmise: cf. per Lord Loreburn (1911) AC, at p 678″. (at p358)”