What is the test for an appeal on questions of fact?

This is what Duff J. said in Voigt v. Groves, supra, at 176-77: I do not forget the rule relating to the weight to be attached to the finding of the trial judge on questions of fact. Where one's view of the intrinsic credibility of individual witnesses is the controlling factor in a case, and where the estimate of such witnesses based upon their demeanour must largely determine the character of that view, an appeal on questions of fact, although given theoretically, is, generally, in practice an appeal in name only. But one cannot refuse to recognize that there is a right of appeal on such questions, and that on an appeal from a judgment after a trial by a judge sitting alone, the hearing of the appeal is a re-hearing of the cause; and where, giving to the views of the trial judge as to the credibility of particular witnesses the weight which is justly due to them, one finds that one cannot reconcile his decision with the inferences one draws from admitted facts, from facts proved by credible witnesses, by documents, from circumstances which are common ground, then I think that generally one should not regard oneself as bound by his conclusions:...