“The palpable and overriding error standard reiterated by the Supreme Court in Housen v. Nikolaisen, 2002 SCC 33 (CanLII), [2002] 2 S.C.R. 235 applies when reviewing factual findings even when those findings are based on a written record. This court has repeatedly stipulated that deference is owed to factual findings made at first instance, even where the appeal is from an entirely written record: see, for example, Waxman v. Waxman, 2004 CanLII 39040 (ON CA), [2004] O.J. No. 1765 (C.A.) and FL Receivables Trust 2002-A v. Cobrand Foods Ltd. 2007 ONCA 425 (CanLII). Although the explanation offered by the court at para. 46 of Fl Receivable refers to trial decisions, it is equally applicable to motions and usefully recalled:
The principle of appellate deference to a trial judge’s fact-finding and inference-drawing applies even when the entire trial record is in writing. That is so because the principle of deference is grounded in more than a trial judge’s ability to see and hear the witnesses. Deference recognizes that even on a written record, the trial judge “lives through” the trial while a court of appeal reviews the record only through the lens of appellate review. Deference also preserves the integrity of the trial process, maintains the confidence of litigants in the process, reduces the number and length of appeals and therefore, the cost of litigation, and appropriately presumes that trial judges are just as competent as appellate judges to resolve disputes justly.”