The Whole Truth: Varieties of Totality

"The truth the whole truth and nothing but the truth." These words are familiar from courtroom dramas. But what do they mean? Debates about the nature of truth have long been prominent in philosophy. But relatively little attention has been given to the question what it is for a statement to be the whole truth, or equivalently, what it takes for a description to be total, rather than merely partial. This project seeks to redress that. We will study the logic and semantics of expressions such as "and that's all'' or "and that's the whole truth" - so-called "totality operators".

The topic is of crucial importance for metaphysics. One of the central questions in metaphysics is what the world is fundamentally like. One candidate answer is materialism, or physicalism, which takes only physical facts to be fundamental. However, this notion of fundamentality is notoriously elusive, and so we need to know more about what materialism amounts to. A typical first stab at an explanation would be this: materialism requires that every fact about the world is entailed by the physical facts. But it has been recognized that this would leave materialism without the fighting chance that it deserves: certain negative truths, like the truth (if it is one) that there are no angels, are not entailed by the physical facts, but nonetheless do not threaten materialism. A plausible remedy that has been suggested is that materialism boils down to the thesis that every truth is entailed by the physical facts together with a "that's all" or "that's the whole truth" clause. This prompts two questions. First, does that thesis adequately capture physicalism? Second, is the thesis philosophically defensible? In our attempt to answer these questions, we will draw on the results of our investigations into the meaning of totality operators.

Outside the context of fundamental metaphysics, totality operators will typically be restricted: not all truths are always relevant, after all. We will study the logic of such restricted totality operators, and apply them to issues in epistemology and in legal theory. One central topic in epistemology concerns the conditions under which one counts as having epistemic justification for believing certain propositions. It is initially appealing to hold that if one has a perceptual experience as of p then one has justification for believing p. But evidence is defeasible. Even though a certain body of evidence provides justification for believing a proposition, an augmented body of evidence may not. As such, the above principles, or any like it, could be exceptionless unless we add to their antecedents some kind of totality clause - a condition to the effect that one has no further evidence or no further 'relevant' evidence or no defeating evidence. Rarely, though, is this totality requirement explained in much detail or investigated formally. We will use specifically epistemic totality operators to illuminate it, and thus to clarify the nature of defeasible reasoning.

The part of the project concerned with legal theory will use case law on perjury as a data source of reflective, yet philosophically untutored intuitions about what counts as "the whole truth", and explore how far formal "that's-it" operators are capable of capturing the meaning of that phrase. This will help to clarify a notoriously difficult legal doctrine. In the theory of legal drafting, lawmakers sometimes try to make statutes "judge proof" by enforcing a tacit "that's-it"-clause that limits the scope of judicial discretion. In the domain of abstract jurisprudential theory, the doctrine of formalism, with its slogan "the positive law is all there is", appears to involve some totality claims. We will investigate to what extent totality operators can be a useful tool in legal drafting, and whether they allows us to give a coherent account of formalism. Our results may lead to improvements in jury instructions and computer-assisted legal drafting.

We will bring the results of our research to two key audiences outside of the higher education sector - legal professionals and members of the general public with an interest in fundamental philosophical questions. We will accomplish this through organising and attending specifically targeted events - the workshop of the Bell Centre for Forensic Studies and Legal Reasoning, the International Conference on Artificial Intelligence & Law, a workshop for the sub-project on legal theory, and a widely advertised public lecture.

In the part of the project concerned with legal theory, we will examine reported court decisions that explicitly reason about the conditions under which the whole truth was or was not told, and ask how we can account for that reasoning through the rigorous formal framework developed in our team. Another relevant class of documents consists of jury instructions, which aim to explain the oath, and the terms used in it, to laypeople. We will examine to what extent they capture the meaning of these terms, and ask whether they could be improved. A refined understanding of how the expression "the whole truth" is to be understood could feed into the guidelines for how judges are to instruct juries, and into the actual jury instructions.

We will work together with legal practitioners and judges to overcome the challenge of expressing theoretical insights about the meaning of the "whole truth" in a non-technical and widely accessible way. Schafer is a member of SIPR, The Scottish Institute for Policing Research, a collaboration between Scottish universities and the Police Service of Scotland. He is also a Co-Director of the Bell Centre for Forensic Statistics and Legal Reasoning, which organises an annual workshop for SIPR on the general topic of Legal Reasoning and Evidence Law. In June 2016, project members will present their work on the meaning of "the whole truth" in legal contexts and on reasoning with incomplete evidence at such a workshop. That workshop is heavily promoted to legal practitioners, judges and police officers, and thus provides the project team with an opportunity to reach one key group outside of the Higher Education sector upon whom our research can have impact.

The workshop organised by the Bell Centre will allow us to identify potential partners within this key group, and invite them - as speakers or delegates as appropriate - to the international workshop on sub-project (d) that we are organising in Edinburgh in March 2017. That workshop will bring together philosophers, legal theorists and legal professionals to offer a range of different perspectives, and will further develop the network for knowledge exchange that we are aiming to build.

Another area where this project can have impact is legal drafting. In this, lawmakers are increasingly assisted by formal and computational tools. Lawmakers may be interested in making law "judge-proof" - reducing the discretion of judges. Alternatively, they may wish to avoid principles that are overly rigid, and to allow judges a certain amount of discretion in considering further factors. Standard formal representations of legal rules and principles are not particularly suited to promote either aim. In contrast, totality operators of the kind that we are going to study seem tailor-made for it. We will look at extant computational tools that assist lawmakers in the task of legal drafting, and examine in what ways they might be improved. Our project thus has the potential to lead to better computer programmes for checking whether new regulations are consistent and complete. We have budgeted for two project members to attend the biennial International Conference on Artificial Intelligence & Law, to take place in mid-2017, to present our work and liaise with experts in computer-assisted legal drafting.

Further, the PI will deliver a public lecture to communicate some of the knowledge gained during the project to a wider audience.