53 The questions submitted by Mr Williams (see [35] above) and by Comcare (see [38] above) are not in terms asking the question whether, on the balance of probabilities (and assuming the material submitted was correct and identified relevantly Mr Williams' personal, medical and employment history), Mr Williams' diabetes was materially contributed to by his employment with RAAF. I do not think it is necessary to imply that there should be one only question submitted to Professor Cohen, or that such questions as were submitted to him should be jointly presented. The important issue is whether Professor Cohen was asked his opinion on the relevant 'causation' question. The utility of the many questions asked by Comcare is not apparent to me, but in a real sense they were preliminary. As I noted, question two of the questions submitted by Mr Williams, asked whether there were any factors or features of his employment which may have contributed to him developing a virus or being exposed to a trigger giving rise to his diabetes. The question was not that agreed to be submitted. It was in a practical sense a preliminary question. If Professor Cohen had answered only that question, his opinion would not have been expressed in terms of the relevant question to be submitted. It would not have given effect to the agreement. However, question 17 of the questions put by Comcare is close to an accurate expression of the question agreed to be submitted. Question 18, in particular by use of the term 'more likely than not', accurately indicates to Professor Cohen the way in which he should address answering the question, as distinct from answering it on the basis of medical opinion with some stronger degree of certainty. The combination of questions 18 and 19 were, presumably, designed to establish a material contribution in the alternative that the employment contributed to the development of diabetes in a more than minimal way.
54 Hence, ultimately, in my judgment the questions as expressed included in a perhaps oblique way the correct question which was agreed to be submitted to Professor Cohen by the expression in questions 17, 18 and 19 of the questions put forward on behalf of Comcare. Despite the complexity of the questions submitted, I do not consider the mere fact of them being submitted from different sources or in the terms in which they were submitted involved such a breach of the agreement of 17 May 2002 as to lead to that agreement coming to an end. I also consider that there was no variation to the agreement on 22 or 31 July 2002 by the fact of the independent correspondence sent to Professor Cohen on behalf of Mr Williams and on behalf of Comcare or its content. I accept that the parties did not address how one set of answers of Professor Cohen to one set of questions were to be reconciled with his answers to the other set of questions. That is because, I think, the parties through their solicitors did not identify clearly and precisely what question or questions were to be asked of Professor Cohen. However, as I have found, it was implied in the agreement of 17 May 2002 what information was to be submitted to Professor Cohen and ultimately what question was to be answered by him. That information was submitted to Professor Cohen, and the correct question was (in the manner I have described) asked of him.
55 The contention of Comcare that Mr Williams breached the agreement by including a description of the relevant law in a way which is inaccurate is one I reject. I do not need to address it in detail. The question which was put to Professor Cohen by or on behalf of Mr Williams was, at least in the sense I have identified, inaccurate. As I have noted earlier, if only that question had been submitted, and answered, the question which was agreed on 17 May 2002 to be submitted to Professor Cohen would not have been submitted to him. The agreement would not have been performed. But the parties, for whatever reason, contemplated a series of questions being submitted. Question two submitted on behalf of Mr Williams was, as were many of the questions submitted by Comcare, preliminary only. If, despite having been asked the correct question (in the manner I have identified), Professor Cohen's opinion had only been responsive to question two as submitted by Mr Williams, then his opinion would not have been in response to the question which the agreement contemplated. It would not have obliged Comcare and Mr Williams to have been bound by it, at least as determining the 'causation' issue. As appears below, I have determined that Professor Cohen did answer the question which the agreement of 17 May 2002 intended that he should answer.
56 It is necessary to refer to the other issues which underlay the agreement made on 17 May 2002. If Professor Cohen said that factors A and B materially contributed to Mr Williams' diabetes, it is a matter of law whether such factors were part of Mr Williams' employment. There will be circumstances where there would be no contest about that issue, for example hearing loss caused by exposure to noise in employment. There will be other circumstances where the factors are clearly unrelated to the employment. It is no part of a medical opinion to determine the answer to such an issue. It was not intended by the parties that Professor Cohen should do so. In my view there was an underlying and unresolved issue to the agreement of 17 May 2002. It appears to have emerged only belatedly perhaps because Comcare had not identified it previously as it did not need to do so given its determinations, as to whether the 'environmental considerations' leading to Mr Williams developing multiple viral diseases, and in turn diabetes (if that is what Professor Cohen concluded) were in fact related to his employment. That is not a factual question dependent upon medical expert evidence, but a legal question in the light of the apparently uncontested facts that Mr Williams was in fact resident in single men's quarters until at least 1989, and that during that time he 'let himself go'.
57 In my judgment, to give the agreement of 17 May 2002 efficacy, there must be implied the term that, in the event that Professor Cohen were of the opinion, on the balance of probabilities, that certain matters or factors relating to Mr Williams' employment materially contributed to his diabetes, the matters or factors as a matter of law bring his claim within the definition of disease in s 4 of the SRC Act. In short, whether those matters or factors as a matter of law amount to the disease being contributed to in a material degree by his employment. The causation component of that definition will have been resolved by the opinion of Professor Cohen. The legal component, whether those causative matters or factors lead to whether the employment itself having materially contributed to the disease is a separate and different issue. Section 14(1) provides for liability in respect of 'injury' in certain circumstances, and 'injury' is defined to include a disease. In the case of an injury that is not a disease, the injury must arise out of or in the course of employment: see ss 6 and 6A. In the case of the disease, the causative requirement contained in the definition of 'disease' involves, in the present circumstances, two steps: whether the alleged factors did materially contribute to the disease, and whether these factors were part of or features or aspects of the employment.
58 Events which occur in the course of employment may mean that a disease was contributed to in a material way by the employment: see e.g. Federal Broom Company Pty Ltd v Semlitch (1964) 110 CLR 626 at 632, 641; Treloar v Australian Telecommunications Commission (1990) 26 FCR 316; Wiegand v Comcare Australia [2002] FCA 1464; (2002) 72 ALD 795.
59 That implied term, depending upon the opinion of Professor Cohen, may need to be determined by the Tribunal. For, in my judgment, the agreement of 17 May 2002 contemplated by necessary implication that Professor Cohen's opinion on the causation issue, if favourable to Comcare, would result in the application to the Tribunal being dismissed by consent. And, if his opinion on the causation issue were favourable to Mr Williams, would result in the Tribunal being asked to substitute a determination favourable to Mr Williams (in its discretion, then remitting to Comcare the function of determining the nature and amount of Mr Williams' entitlement under the SRC Act), subject to the legal issue arising to which I have referred. If Professor Cohen had identified causative factors which clearly were part of Mr Williams' employment, such an issue would pass sub silentio because the answer would be obvious. In this instance, Comcare has raised that issue and the Tribunal, depending upon Professor Cohen's opinion, may need to address it.
60 I find some difficulty in identifying how Professor Cohen addressed the critical question required to be addressed by him. That is because it was not put to him in terms. I have explained why that is so, namely as a consequence of the complex (in the case of Comcare) and inaccurate (in the case of Mr Williams) questions which were put to him on the issue. However, despite the way in which question two of Mr Williams' questions was framed, it appears (see [44]), that Professor Cohen addressed that question on the balance of probabilities and on the basis that it asked whether the diabetes in fact, rather than whether it may have, been caused or contributed to by his employment condition. Professor Cohen expressed the positive view that Mr Williams:
1. prior to his RAAF service was not predisposed to repeated viral infections;
2. subsequent to, and apparently by reason of, the nature of his living habits in single men's quarters, developed repeated viral infections; and
3. his susceptibility to repeated viral infections then led to his diabetes, at least as a material contributing factor to the onset of his diabetes.