Are obvious opinions irrelevant or just unhelpful?

A witness who gives the court an opinion may have no better information than that already available to the court, and may be in no better position to come to an opinion than the fact-finder.

In such a case the admissibility of the witness’s opinion is (in New Zealand) governed by ss 23 – 25 of the Evidence Act 2006. Evidence of an opinion is not admissible in a criminal case except pursuant to ss 24 and 25.

Section 24 provides:

A witness may state an opinion in evidence in a proceeding if that opinion is necessary to enable the witness to communicate, or the fact-finder to understand, what the witness saw, heard, or otherwise perceived.

Where the fact-finder is in just as good a position as the witness to form an opinion, the s 24 requirement of necessity is not met. Section 24 does not, in such a case, allow the opinion to be given in evidence.

Sometimes a witness will have specialised knowledge, not available to the fact-finder, on which an opinion is based. Then the admissibility of the opinion will be governed by s 25. Subsection (1) provides:

An opinion by an expert that is part of expert evidence offered in a proceeding is admissible if the fact-finder is likely to obtain substantial help from the opinion in understanding other evidence in the proceeding or in ascertaining any fact that is of consequence to the determination of the proceeding.

The definitions of opinion, expert, and expert opinion in s 4 are explanatory and consistent with ordinary usage.

Merely satisfying the criteria in ss 23 or 24 does not render opinion evidence necessarily admissible, as it may be excluded by another provision of the Act, such as s 8 (prejudicial effect exceeding probative value).

In a recent decision, currently suppressed ([2017] NZCA 430), our Court of Appeal has held that another section that may apply to exclude opinion evidence that does not go further than the fact-finder can go without the witness’s opinion, is s 7. This is headed “Fundamental principle that all relevant evidence admissible”, and reads:

(1) All relevant evidence is admissible in a proceeding except evidence that is—

(a) inadmissible under this Act or any other Act; or

(b) excluded under this Act or any other Act.

(2) Evidence that is not relevant is not admissible in a proceeding.

(3) Evidence is relevant in a proceeding if it has a tendency to prove or disprove anything that is of consequence to the determination of the proceeding.

In effect, the Court of Appeal has read words into subsection (3), as if it read (adding the blue words):

(3) Evidence is relevant in a proceeding if it has a tendency to prove or disprove anything and is capable of assisting the fact-finder in determining anything that is of consequence to the determination of the proceeding.

The Court drew that from dicta requiring evidence to  be reasonably capable of supporting the fact in issue: Bain v R [2009] NZSC 16 at [40].

I do not think that it was necessary for the Court of Appeal to read words into s 7. An opinion, as defined, on a fact in issue will necessarily be relevant, unless it is equally consistent with proof, as with disproof, of the fact in issue. It will have a tendency to prove or disprove something of consequence to the determination of the proceeding, just as the fact-finder’s opinion will. The point is that, in the case that has given rise to this discussion, the witness’s opinion had no more probative value than the opinion that the fact-finder could come to independently. It was relevant, but inadmissible because it did not satisfy the requirements of ss 24 or 25: it was not “necessary” and it was not likely to give the fact-finder “substantial help”.

Beyond reasonable doubt

We may agree on what something is, even if we disagree on how it should be described. We may both be looking at a circle; you may describe it as having a circumference of a particular length, while I may describe it as having a radius of a particular length.

Do we have to agree on how to describe what “reasonable doubt” means? Does it have a utilitarian or a pragmatic function; is it a quality like “good” (remembering GE Moore’s difficulty in defining “good”). Does it have a function at all, or is it just a feeling?

Is it describable in terms of knowledge? To ask “what do I know” is to summon the ideas of knowledge and belief. What are the conditions that I require to be satisfied before I am prepared to say I believe something? Do I rely on experience, feeling, logic, or persuasive rhetoric? Do I have to use the same criteria for belief as you use?

Often juries will ask judges for a definition of “beyond reasonable doubt”. While courts may differ in their responses, do their differences conceal an agreement?

I have previously discussed the leading New Zealand case on this: R v Wanhalla [2006] NZCA 229; [2007] 2 NZLR 573. Now the High Court of Australia has considered the same issue: The Queen v Dookheea [2017] HCA 36 (13 September 2017).

The HCA prefers that explanations of what proof beyond reasonable doubt means should not be attempted, and in particular a contrast with proof beyond any doubt should be avoided. It is, however, acceptable and even useful to contrast the high criminal standard of proof beyond reasonable doubt with the lower civil standard of proof on the balance of probabilities. “[A] reasonable doubt is a doubt which the jury as a reasonable jury considers to be reasonable (albeit, of course, that different jurors might have different reasons for their own reasonable doubt)” (at [34]), and ([35]):

“... it is the votes of each of the individual members of the jury that are determinative of the verdict of the jury as a whole. Each juror is appointed to consider the evidence and to decide whether it satisfies him or her of guilt beyond reasonable doubt; and, in order to discharge that function, each individual member of the jury must in effect enquire of himself or herself whether he or she entertains a reasonable doubt. In practical reality, each individual juror may at some point in the course of the juror's consideration of an issue have a doubt which, upon reflection and evaluation, he or she is disposed to discard as an unreasonable doubt.”

Clumsily put, if one objects to unnecessary gender pronouns, but there you are.

In New Zealand, explanations of beyond reasonable doubt may be attempted: acceptable is, “an honest and reasonable uncertainty left in your mind about the guilt of the accused after you have given careful and impartial consideration to all of the evidence.” But this is not mandatory, and it “is sufficient to make it clear that the concept [of proof beyond reasonable doubt] involves a high standard of proof which is discharged only if the jury is sure or feels sure of guilt.” Focusing on doubt may be misleading, because a doubt need not be articulable and what is required is proof to the required standard. It is acceptable to tell a jury that proof to a certainty is not required. But it is wrong to tell a jury that they need to be as sure of guilt as they would be about an important decision in their own lives.

Don’t ask for more: lawyers are not philosophers. The law does, however, cherry-pick the philosophies it wants.

Utilitarianism asks, what is in the best interests of society? Individual interests are subordinate to society’s interests, individual rights are minimised, and as far as crime is concerned, a deterrent policy is pursued to protect the peace of the community. On the topic of the criminal standard of proof, a utilitarian would acknowledge that it must be higher than the civil standard, but not all that much higher.

A pragmatist would ask, what works? The ends justify the means. Pragmatism may strive for a workable balance between utilitarianism and morality. While absolute proof of a criminal charge is not required, pragmatism justifies a high, but not too high, standard of proof.

A moral view (and here I  acknowledge that these are all moral theories, but I just say "moral" here to avoid having to say deontological) is that it is better to let (insert your preferred number) guilty people go free than to convict one innocent person. It reflects a judgement about what is right or good in the context of a criminal trial, and it favours a very high standard of proof.

These themes are found in the various approaches to instructions on the standard of proof. To say that the standard is higher than the civil standard is to make a utilitarian point. It doesn’t get very far by way of explanation, but it is a start. To add that the fact-finder must “be sure” on a “reasonable” assessment of the evidence, is a pragmatic theme, taking the explanation beyond the utilitarian but not pushing it as far as morality would claim it should be taken. Also pragmatic is the illustration of taking the care one would take over an important decision in one’s own life. To say that proof to a mathematical certainty is not required but the standard is nevertheless very high, is to emphasise the moral theme.

Another area of the law in which these three themes are illustrated is the part of the law of evidence which concerns the decision whether to exclude improperly obtained evidence. A balancing model is widely used for this (and in New Zealand is enacted in s 30 of the Evidence Act 2006). Factors favouring admission of improperly obtained evidence are utilitarian: society is best served if people charged with offences have trials on all the available evidence. Exclusion factors are moral, reflecting the idea that those who enforce the law should obey the law. The balance between these factors is struck pragmatically: what is required for an effective and credible system of justice?

You can't really be surprised when a jury wants assistance with the concept of proof beyond reasonable doubt. Nor at the reluctance of judges to get into the extent to which deontological ethics may be modified by pragmatism. It should be reassuring, however, to remember that philosophy is just simple ideas dressed up in hard words, in contrast to law which is hard ideas dressed up in simple words.