Taking the Evolution of the Standards of Proof for a Criminal Conviction Seriously

• Pages: 155-215
• Date: 01 January 2025
• Published date: 01 January 2025
• Author: Jacopo Della Torre
• Subject Matter: Criminal Law

Quaestio facti. Revista Internacional sobre Razonamiento Probatorio / International Journal on Evidential Legal Reasoning

Año 2025 8 pp. 155-216 DOI: 10.33115/udg_bib/qf.i8.23112

Quaestio facti. Revista Internacional sobre Razonamiento Probatorio

Quaestio facti. International Journal on Evidential Legal Reasoning

Sección: Conjeturas y refutaciones

2025 l 8 pp. 155-216

Madrid, 2025

DOI: 10.33115/udg_bib/qf.i8.23112

Marcial Pons Ediciones Jurídicas y Sociales

© Jacopo Della Torre

ISSN: 2604-6202

Recibido: 08/01/2025 | Aceptado: 15/01/2025 | Publicado online: 28/01/2025

Editado bajo licencia Reconocimiento 4.0 Internacional de Creative Commons

TAKING THE EVOLUTION OF THE STANDARDS OF PROOF

FOR A CRIMINAL CONVICTION SERIOUSLY*

Jacopo Della Torre

Associate professor of Criminal procedure

University of Genoa, Italy

jacopo.dellatorre@unige.it

ABSTRACT: e article oers a diachronic and comparative analysis of dierent standards of proof

for a criminal conviction. e rst part focuses on the attempt of medieval and early modern Ro-

man-canon systems to clarify this type of rule through a network of legal proofs. e second part

analyses the origins of the main standards for a criminal conviction used today: moral certainty,

beyond reasonable doubt and intime conviction. e nal part looks to the future, asking whether

traditional decision-making criteria should be maintained or replaced by new ones based on the

principles of contemporary epistemology.

KEYWORDS: standard of proof; reasonable doubt; moral certainty; intime conviction; legal proof.

SUMMARY: 1. INTRODUCTION.— 2. CONCEPTUAL AND TERMINOLOGICAL PREMIS-

ES.— 3. THE (SHATTERED) DREAM OF PRE-MODERN ROMAN-CANON SYSTEMS:

THE RATIONALISATION OF STANDARDS OF PROOF THROUGH LEGAL PROOF

RULES: 3.1. e standard of luce meridiana clariores and its functional connection with the legal

* I presented an earlier version of this work in Milan (Bocconi University, 7 March 2024). I also

presented some of the ideas in this article at an online conference organised by the University of Not-

tingham on 28 November 2024. I am grateful to all the participants at these events who commented on

my work. In particular, I would like to thank Diego Dei Vecchi, Paul Roberts and Giovanni Tuzet. I am

also grateful to Paul Roberts for his hospitality at the University of Nottingham, which was essential for

the English and US parts of the research. A previous version of this article appeared as Della Torre 2023a.

Finally, I thank the reviewers of this journal for their constructive comments on the submitted draft.

156 JACOPO DELLA TORRE

Quaestio facti. Revista Internacional sobre Razonamiento Probatorio / International Journal on Evidential Legal Reasoning

Año 2025 8 pp. 155-216 DOI: 10.33115/udg_bib/qf.i8.23112

proof rules; 3.2. e operational diculties of the Roman-canon system of legal proof: the rise of

the confession and the problem of the indicia indubitata.— 4. THE ORIGIN OF MORAL CER-

TAINTY AND REASONABLE DOUBT: 4.1. e theological background; 4.2. e Anglo-Sax-

on experience; 4.3. e Roman-canon experience.— 5. THE COLLAPSE OF THE SYSTEM

OF LEGAL PROOF AND THE EMERGENCE OF THE INTIME CONVICTION: 5.1. e

Enlightenment criticism of legal proof rules; 5.2. e rise of the two-faced rule of intime convic-

tion; 6. THE AMERICAN EXPERIENCE AND THE ENGLISH DEVIATION.— 7. THE

BARD’S AGE.— 8. CONCLUSIONS: WHAT STANDARD OF PROOF FOR A CRIMINAL

CONVICTION FOR THE FUTURE OF CRIMINAL JUSTICE?— BIBLIOGRAPHY.

1. INTRODUCTION

In recent years, the issue of standards of proof has received increasing attention

in both common law and civil law jurisdictions 1. As we shall see (§ 7), the reasons

for this transversal interest are manifold. In some countries, the phenomenon has

been encouraged by legislative attempts to explicitly codify evidentiary thresholds

that were previously only implicit. In other cases, it has been the case law that has

sought to better dene the rules of decision-making. Finally, certain supranational

institutions—such as the European Court of Human Rights—have also played an

important role.

However, despite the wide range of the debate that has developed on this subject,

it should be noted that the results obtained are rather heterogeneous and not without

ambiguities. Suce it to say that there is no unanimity even on some fundamental

aspects, such as the denition of the concept of “standard of proof” 2, or on the real

capacity of this type of rule to contribute to the proper functioning of legal systems.

While there are those who are in favour of the primary importance of this category

(Ferrer Beltrán and Tuzet, 2018, p.455 .), there are also those who are of the opin-

ion that standards of proof are nothing more than a relic of the past that we could

well do without (Nieva Fenoll, 2020, p.119 .). As we shall later see (§ 2), at the

heart of these opposing visions lies a bitter dispute between those who, for legal and

moral reasons, consider it possible and/or desirable to establish objective or intersub-

jective thresholds of proof, and those who, for various reasons, oppose this thesis.

e aim of this article is to take a step forward through a diachronic and com-

parative analysis dedicated to a particularly problematic category of standards: those

aimed at determining the quantum of proof required for a criminal conviction. To

understand the delicate nature of this issue, it is enough to recall that one of the most

1 See Allen (2013, p.43 .); Ambos (2023, p.167 .); Clermont (2013); Ferrer Beltrán (2021b);

Id. (2007, p.149 .); Laudan (2006); Poli (2023); Nance (2016); Nieva Fenoll (2010, 85 .); Stella

(2003, p.116 .); Summers (2023, p.264 .); Taruo (2009, p.218 .); Tuzet (2023, pp.226-247

and 264-274).

2 As Roberts and Zuckerman (2022, p.267) point out «what, exactly, is a criminal standard of

proof? is question is more complex, and its answer more controversial, than widely appreciated».

TAKING THE EVOLUTION OF THE STANDARDS OF PROOF FOR A CRIMINAL… 157

Quaestio facti. Revista Internacional sobre Razonamiento Probatorio / International Journal on Evidential Legal Reasoning

Año 2025 8 pp. 155-216 DOI: 10.33115/udg_bib/qf.i8.23112

authoritative European scholars admitted that «la degré de certitude qui conditionne

la décision de culpabilité est une des questions les plus obscures du droit pénal» (Del-

mas-Marty, 1996, p.59).

e structure of the essay is as follows: after some introductory clarications on

the concept of “standard of proof”, which are intended to show how these rules full

several essential roles for the proper functioning of legal systems (§ 2), the rst part

focuses on its use in pre-modern and early modern Roman-Canon legal systems (§

3). is part of the analysis has a specic purpose: to draw attention to one of the

most ambitious attempts to make standards of proof less subject to the arbitrary

power of adjudicators, perpetuated by the creation of a complex network of legal

proof rules 3. is was an experience that proved unsuccessful in the long run, but

not for that reason unable of providing valuable lessons for the present day.

e second part of the article (§§ 4-7) contains a diachronic analysis of the or-

igins and development of the principal standards of proof still used today for the

imposition of punishment: moral certainty, beyond any reasonable doubt (hereafter

BARD) and, nally, intime conviction. is will show that not only do these rules

have very distant origins in time, but that they are also closely connected. And it is

also because these rules are the fruit of cultural and legal changes that took place

centuries ago that, as we shall see, interpreters today struggle so much to identify a

minimal meaning of them.

Awareness of this fundamental historical fact will be the starting point for the last

part of the work (§8), which will be devoted to understanding whether it is appro-

priate in contemporary legal systems to continue to maintain the traditional rules of

decision-making, or whether, as some scholars argue, they should be replaced by new

ones based on the principles of contemporary epistemology.

2. CONCEPTUAL AND TERMINOLOGICAL PREMISES

It is well known that the factual assertions made by the parties in legal proceed-

ings are mere hypotheses which, as such, may be true or false (Taruo, 2009, p.218).

Reducing this background uncertainty is one of the most delicate tasks of the law of

evidence. By supporting «the factual claims made by the parties and the ndings of

fact made by the decision-makers» (Tuzet, 2021, p.90), evidence ensures that the

truth remains the point of reference that guides the direction in which the judicial

process must move 4. But when can a hypothesis about a fact be said to have reached

such a level of corroboration that it can be considered suciently proven? To provide

3 For a recent English-language overview of the Roman-canon system of legal proof, see Damaška

(2019).

4 On this point, see Caprioli (2017, p.317 .); Ferrer Beltrán (2004); Summers (2023, p.249 .);

Taruo (2009b); Ubertis (2021, p.2).