Introduction

Restrictions on the admissibility of evidence are closely connected with the establishment of the truth in civil procedure. It is obvious that restrictions and especially the exclusion of evidence would hinder the quest for the truth in certain cases. Restrictions are also closely related to the principle of procedural justice. Procedural justice presupposes that just results should be obtained through a just procedure – fairness of procedure. To be able to talk about fairness, procedure should be oriented towards correctness. However, is it possible to have correctness in the procedure with evidence obtained illegally or in violation of human rights?

The equality principle generally favours the admissibility of all evidence relevant to the trial. By excluding a piece of relevant evidence categorised as inadmissible, evidence law places the risk of error associated with this evidence on its proponent, whose opponent consequently acquires an immunity from that risk. This one-sided outcome is generally inferior to a system of free proof. Arguably, a free-proof system apportions the risk of error more equitably by allowing factfinders to consider all relevant evidence and determine its probative value on a case-by-case basis. This system avoids any systematic skewing of the risk of error. Fact-finding errors are thus entirely accidental in their occurrence. Free proof, however, only guarantees rudimentary equality in risk allocation and is still far from guaranteeing equality in the final apportionment of the risk of error. Application of this system in civil litigation only installs primary equality and requires corrective equality mechanisms. These mechanisms render inadmissible any evidence (or impose other restrictions on evidence) that creates inequality between the litigating parties by imposing a non-reciprocal – and, therefore, inequitable – risk of error on the opponent.

These corrective mechanisms can include evidentiary privileges, restricting the means of evidence, restricting methods of taking evidence, prohibiting specific evidence or a general exclusion of evidence. The problem has cross-border dimensions – the question of whether a court of another country will accept evidence taken in the first country, for example in a manner that is considered to be problematic. Another problem is the feasibility of taking evidence in another country in case of evidence that is considered illegal according to the lex fori. These problems are also problematic in the enforcement stage, e.g. as regards enforceability of the judgment in another country.