La prova del nesso causale nella responsabilità per inadempimento: prospettive dottrinali e soluzioni giurisprudenziali a confronto

The proof of casual relation in contractual liability is closely connected to the approach adopted with respect to the allocation of the burden of proof under art. 2697 of the Civil Code. According to a well-settled understanding of art. 1218 of the Civil Code proposed by scholars and partially endorsed by case law, since the obligatory relationship is aimed at satisfying the creditor’s interest through the debtor’s performance, the harmful event arising from the non-performance (or from a not duly performed execution) should be directly attributed to the latter. Some authors differently affirm that evidence of the causal relation between non-performance and harm should be provided by the creditor. Such approach is however in contrast with a strict interpretation of the letter of the law: in this sense, the only causal relation to be proved concerns the identification of the non-attributable cause of the event for the purpose of discharging the debtor from any liability. The recent case law of the Supreme Court puts causal relation as an element of the debtor’s liability, particularly in the context of professional liability: the consequence is that ascertaining the causal relation becomes in fact demanded to the expert evidence. The paper analysis the different theories on the allocation of the burden of proof between debtor and creditor, by assessing their consistency with the rules governing contractual liability. The paper then points out how the difficulty of reaching clear results in the assessment of the causal relation generally pushes the judge to delegate such activity to the expert evidence. The risk, however, is that the rationale underlying the expert decision can be hardly challenged.