Whether a court's ruling is based on oral testimony or written declarations, when conflicting inferences can reasonably be drawn from the facts, can the appellate court defer to the trial court's factual determinations?

Whether a trial court's ruling is based on oral testimony or written declarations, when conflicting inferences can reasonably be drawn from the facts, an appellate court must defer to the trial court's factual determinations. (Shamblin v. Brattain (1988) 44 Cal.3d 474, 478-479.) "When two or more inferences can reasonably be deduced from the facts, the reviewing court has no authority to substitute its decision for that of the trial court." (Ibid.)