19.1 There may be many factors contributing to an event and its consequences. Rules of causation provide a means of distinguishing between those causes which trigger liability and give rise to certain defences in accordance with the contractual relationship between assured and insurer.1 In general, whether or not a loss is covered by a marine policy depends on ascertaining its proximate cause.2 The burden is on the claimant to prove his case, so, if he fails to prove on a balance of probabilities that he has suffered a loss caused by an insured peril, his claim will fail, regardless of whether or not, and to what extent, the defendant can adduce an explanation for the loss.3