In my opinion, what the primary judge is saying in those paragraphs is that there is little, if any, dispute in the medical evidence, in so far as it indicated that in each case medical considerations alone left a possibility that the cause was asphyxiation, this being a reasonable possibility and not a possibility which was merely remote or fanciful; and that there was no other cause which could be considered as something more than a reasonable possibility. The primary judge having approached the matter in that way, I think it is appropriate for this Court to do likewise, and consider whether, treating the medical evidence in that way, it considers the primary judge erred in holding that the s.101 test was satisfied.
30 In my opinion, the other principal submission of the applicant is based on a misconception of the principles concerning circumstantial evidence. As shown by Shepherd v. The Queen (1990) 170 CLR 573, it is of the essence of circumstantial evidence that the totality may prove a case beyond reasonable doubt whereas each piece of evidence considered on its own may prove nothing and may even be considered irrelevant in the absence of other evidence. In this case, if it be the case that it is only the occurrence of four deaths in similar circumstances that could prove that the applicant was responsible for any one of them, and that the evidence relating to any one of them without the evidence relating to the others would prove nothing, then this would not of itself mean that the Pfennig test could not be satisfied.
31 In my opinion, it is necessary in relation to each count for the Court to consider the evidence relating to that count in the absence of evidence relating to the other counts, and consider whether any deficiency of proof of the appellant's responsibility for the death or ALTE in question would be overcome by the evidence relating to the other counts, so that the latter evidence would leave no rational view consistent with innocence in relation to the particular count being considered.
32 The primary judge did not explicitly undertake that course, but in my opinion that is the substance and effect of what he did. Furthermore, my own view is that, on following that course in relation to each count, there would be a deficiency of proof of guilty in relation to each count without evidence concerning the other children, but that the additional evidence concerning the other children would leave no rational view consistent with innocence in relation to the particular count being considered. I say so essentially for the reasons given by the primary judge, especially the extreme improbability of four such deaths and one ALTE occurring to children in the immediate care of their mother, with asphyxiation being a substantial possibility and no other cause of death being anything more than a substantial possibility, without the mother having contributed to any of those deaths, particularly in the light of the diary entries referred to by the primary judge. The contribution to the death may have been an unlawful act amounting to manslaughter rather than murder, but that would be sufficient in my view to satisfy the Pfennig test, when manslaughter is an alternative verdict available on a charge of murder.
33 As to whether there would be prejudice arising from confusion from the way the matter was left to the jury, it seems to me that the following course could be taken. The jury could be asked to consider first whether there is any reasonable possibility that all deaths and the ALTE occurred by natural causes without any contribution from the applicant. If they do consider there is such reasonable possibility, that would be the end of the matter and a verdict of not guilty should be returned on all counts. If they consider there is no reasonable possibility that all incidents occurred by natural causes without a contribution from the mother, it would be pointed out that that conclusion does not mean that there was a contribution from the mother in each and every individual case, and it is necessary then to turn to consider the evidence in each individual case. The judge would then explain to the jury what evidence could be considered in relation to each count. There is a possibility of confusion, and I accept that this is prejudice within s.101, as well as ss.137 and 135. However, I think that the probative value of the evidence is such that it does substantially outweigh any prejudicial effect, so that the s.101 test is passed. In my opinion also, the evidence would not be excluded under s.137 or s.135.
34 In my opinion, in relation to each count, the evidence concerning the other counts and other children is admissible as coincidence evidence. That view is sufficient to justify refusing separate trials. It is not necessary to consider whether the evidence is admissible as tendency evidence.