Epistemology applied to conclusions of expert reports

It is believed that to build a robust reasoning logic to make probabilistic inferences in forensic science from a merely mathematical or logistical viewpoint is not enough. Mathematical logic is the positive science of reasoning and as for that it is only interested in the positive calculus of its validity, regardless any prior ontological assumption. But without a determined ontology and epistemology which imply to define the concepts that they will use, it seems difficult that the proposed scientifically correct mathematical solution be successful as a European standard for making conclusions in forensic reports because it has to be based on judicial language. Forensic experts and Courts are not interested in the development of a positive science but in a practical science: in clarifying whether certain known facts are related to a possible crime. Therefore, not only the coherence of the demonstrative logic reasoning used (logic of propositions) is important, but also the precision of the concepts used by language and consistency among them in reasoning (logic of concepts). There is a linguistic level essential for a successful communication between the forensic practitioner and the Court which is mainly related, in our opinion, to semantics and figures of speech. The first one is involved because words used in forensic conclusions often have different meanings - it is said that they are polysemic - and the second one because there is often metonymy as well. Besides, semantic differences among languages regarding words with the same etymological root add another difficulty for a better mutual understanding. The two main European judicial systems inherit a wide and deep culture related to evidence in criminal proceedings and each of them has coined their own terminology but there are other two more abstract levels such as logical and epistemological, where we can find solid arguments by which terms used at legal level on conclusions of forensic reports could be accurate and consistent for all users of an intended EU guideline. An effort has been made to elucidate the following terms: truth, certainty, uncertainty, opinion, conjecture, probability, evidence, belief, credibility, determinism, indeterminacy, cause, principle, condition, and occasion.