Bushell v Repatriation Commission

[1992] HCA 47

HIGH COURT OF AUSTRALIA

Mason CJ, Brennan, Deane, Dawson, Toohey and McHugh JJ

BUSHELL v. REPATRIATION COMMISSION

(1992) 175 CLR 408

7 October 1992

Repatriation Pension

Repatriation Pension—Incapacity arising from war-caused injury or disease—Connexion between incapacity and war service—Commission required to find incapacity war-caused unless satisfied beyond reasonable doubt that no sufficient ground for so finding—Commission required to be so satisfied if of opinion that material does not raise reasonable hypothesis connecting incapacity with service—Relationship between requirements—"Reasonable hypothesis"—Veterans' Entitlements Act 1986 (Cth), s. 120.

Decisions

MASON C.J., DEANE AND McHUGH JJ. The question in this appeal is whether the Administrative Appeals Tribunal (Veterans' Appeals Division) misdirected itself in holding that no reasonable hypothesis connected the essential hypertension of the appellant with an anxiety state arising from the circumstances of his war service. The Tribunal accepted that essential hypertension "is a form of hypertension for which there is no organic explanation and the cause of which is unknown". The Tribunal held that "the hypothesis of stress as contributing to the onset of essential hypertension ... is not reasonably based". An appeal to the Federal Court against the decision of the Tribunal was allowed by Wilcox J. on two grounds: (a) that the evidence which the Tribunal accepted did not support its finding; (b) that the Tribunal had failed to deal with an alternative case advanced by the appellant which claimed a relationship between his war-caused alcoholism and his hypertension. His Honour ordered that the matter be remitted to the Tribunal for a rehearing. An appeal against his order was allowed by a majority of the Full Court of the Federal Court (Morling and Neaves JJ., Davies J. dissenting). The majority ordered that the claim of the appellant should be reheard only in respect of the second of the two grounds which Wilcox J. had upheld.
The legislation

2. Section 13(1) of the Veterans' Entitlements Act 1986 (Cth) provides:
"Where: (a) the death of a veteran was war-caused;
or (b) a veteran has become incapacitated from a war-caused injury or a war-caused disease; the Commonwealth is, subject to this Act, liable to pay: (c) in the case of the death of the veteran - pensions to the dependants of the veteran; or (d) in the case of the incapacity of the veteran - pension to the veteran; in accordance with this Act."

3. The term "veteran" is defined, inter alia, to mean "a person ... who (has) ... rendered eligible war service", as defined. It is common ground that the appellant is a veteran for the purposes of s.13.

4. Section 120 of the Act lays down the manner in which the Tribunal is to determine a claim under Pt II (which includes s.13) where the claim involves a relationship between a veteran's injury and his or her operational service. Section 6 defines the term "operational service". It is common ground that the appellant rendered operational service within the meaning of the definition. Section 120 provides:
"(1) Where a claim under Part II for a pension in respect of
the incapacity from injury or disease of a veteran, or of the death of a veteran, relates to the operational service rendered by the veteran, the Commission shall determine that the injury was a war-caused injury, that the disease was a war-caused disease or that the death of the veteran was war-caused, as the case may be, unless it is satisfied, beyond reasonable doubt, that there is no sufficient ground for making that determination. ... (3) In applying subsection (1) or (2) in respect of the incapacity of a person from injury or disease, or in respect of the death of a person, related to service rendered by the person, the Commission shall be satisfied, beyond reasonable doubt, that there is no sufficient ground for determining: (a) that the injury was a war-caused injury or a defence-caused injury; (b) that the disease was a war-caused disease or a defence-caused disease; or (c) that the death was war-caused or defence-caused; as the case may be, if the Commission, after consideration of the whole of the material before it, is of the opinion that the material before it does not raise a reasonable hypothesis connecting the injury, disease or death with the circumstances of the particular service rendered by the person. (4) Except in making a determination to which subsection (1) or (2) applies, the Commission shall, in making any determination or decision in respect of a matter arising under this Act or the regulations, including the assessment or re-assessment of the rate of a pension granted under Part II or Part IV, decide the matter to its reasonable satisfaction. (5) Nothing in the provisions of this section, or in any other provision of this Act, shall entitle the Commission to presume that: (a) an injury suffered by a person is a war-caused injury or a defence-caused injury; (b) a disease contracted by a person is a war-caused disease or a defence-caused disease; (c) the death of a person is war-caused or defence-caused; or (d) a claimant or applicant is entitled to be granted a pension, allowance or other benefit under this Act. (6) Nothing in the provisions of this section, or in any other provision of this Act, shall be taken to impose on: (a) a claimant or applicant for a pension or increased pension, or for an allowance or other benefit, under this Act; or (b) the Commonwealth, the Department or any other person in relation to such a claim or application; any onus of proving any matter that is, or might be, relevant to the determination of the claim or application."

5. There is no presumption that the injury, disease or death of a veteran was war caused: s.120(5). On the other hand, the claimant for a pension to which s.120 applies has no "onus of proving any matter that is, or might be, relevant to the determination of the claim or application": s.120(6). That being so, the claim, having been made, must succeed unless the Commission "is satisfied, beyond reasonable doubt, that there is no sufficient ground for making that determination": s.120(1). However, the meaning of the expression beyond reasonable doubt is not left at large. Satisfaction beyond reasonable doubt is deemed to be established if, after considering the whole of the material before it, the Commission is of the opinion that that material "does not raise a reasonable hypothesis connecting the injury, disease or death with the circumstances of the particular service rendered by the person": s.120(3). But does this mean, as counsel for the Commission contended, that s.120(3) exhaustively defines the content and the application of the concept of "reasonable doubt" mentioned in s.120(1)? Or does it mean, as counsel for the appellant contended, that s.120(3) merely states an evidentiary threshold which must exist before s.120(1) is given its natural and ordinary meaning?
The relationship between s.120(1) and s.120(3)

6. Notwithstanding the submission of counsel for the Commission, s.120(3) is not exhaustive of the content of s.120(1). Sub-section (3) is concerned with whether "the material" raises a reasonable hypothesis that the relevant injury, disease or death was connected with the service of the veteran. It is not concerned with conflicts in the material, whether they be of opinion or fact. The purpose of sub-s.(3), as demonstrated by its terms and its history, is to ensure that a claim to which s.120 applies is not met unless there is some material which raises the relevant causal hypothesis. Its principal purpose is to overcome the effect of the judgment of this Court in Repatriation Commission v. O'Brien ((1) (1985) 155 CLR 422, at pp 433-434) where the majority held that it was not the law that the Commission must be satisfied that there were insufficient grounds to support the claim if the material in the case did not "provide some positive inference in favour of the requisite connexion between death or incapacity and war service". The Explanatory Memorandum to the Bill which became the Veterans' Entitlements Act stated:
"Sub-clause 119(3) (i.e. s.120(3)) will negate the effect of
the 1985 decision of the High Court of Australia in Repatriation Commission v. O'Brien. A pension will not be payable in circumstances where the evidence does not provide some positive inference in favour of a connection between the injury, disease or death and the veteran's or member's particular service. The sub-clause will require the Commission to refuse the claim where, at the end of the Commission's consideration of the material before it, no reasonable hypothesis that there is such a connection has been raised, and if raised, no such reasonable hypothesis remains."

7. An addition to the Explanatory Memorandum stated:
"It is intended under sub-clause 119(3) that there must be
some material before a determining authority for it to make a judgement on whether it is satisfied beyond reasonable doubt that there is no sufficient ground to grant a claim."

8. The material will raise a reasonable hypothesis within the meaning of s.120(3) if the material points to some fact or facts ("the raised facts") which support the hypothesis and if the hypothesis can be regarded as reasonable if the raised facts are true. Clearly enough, a relevant consideration in forming an opinion whether a particular hypothesis is reasonable is whether, as a matter of common or medical experience, the occurrence of an injury etc. of the kind sustained by the veteran is commonly accompanied by or associated with the occurrence of raised facts of the kind which constitute the relevant incidents of the service of the veteran. However, a hypothesis may still be reasonable even though such an accompaniment or association is not demonstrated or even if it is shown to be uncommon. So, in determining whether a hypothesis is reasonable for the purpose of s.120(3), it is not decisive that a connection has not been proved between the kind of injury which occurred and circumstances of the kind which constitute the relevant incidents of the veteran's service. Nor is it decisive that the medical or scientific opinion which supports the hypothesis has little support in the medical profession or among scientists. Thus, in The Commissioner for Government Transport v. Adamcik ((2) (1961) 106 CLR 292), this Court held that there was reasonable evidence to support a claim for damages that emotional disturbance, brought on by an accident, had caused acute lymphatic leukaemia even though only one doctor supported the claim, others rejected it, and there was evidence that for nearly 20 years the medical literature had discarded earlier suggestions that some cases of leukaemia had been the result of trauma. Windeyer J. said ((3) ibid., at p 306): "The most that could be urged against Doctor Haines' evidence
is that the cause of leukaemia is not, in a positive sense, known and that his view is thus unproven and not accepted by others: not that it can be scientifically established as false."

9. However, a hypothesis cannot be reasonable if it is "contrary to proved scientific facts or to the known phenomena of nature" ((4) ibid.). Nor can it be reasonable if it is "obviously fanciful, impossible, incredible or not tenable or too remote or too tenuous" ((5) East v. Repatriation Commission (1987) 74 ALR 518, at p 533).

10. But leaving aside cases of those kinds, the case must be rare where it can be said that a hypothesis, based on the raised facts, is unreasonable when it is put forward by a medical practitioner who is eminent in the relevant field of knowledge. Conflict with other medical opinions is not sufficient to reject a hypothesis as unreasonable. As we have earlier pointed out, it is not the function of s.120(3) to require the Commission to choose between competing hypotheses or to determine whether one medical or scientific opinion is to be preferred to another. This does not mean, however, that in performing its functions under s.120(3) the Commission cannot have regard to the medical or scientific material which is opposed to the material which supports the veteran's claim. Indeed, the Commission is bound to have regard to the opposing material for the purpose of examining the validity of the reasoning which supports the claim that there is a connection between the incapacity or death and the service of a veteran. But it is vital that the Commission keep in mind that that hypothesis may still be reasonable although it is unproved and opposed to the weight of informed opinion.

11. If the material does raise a reasonable hypothesis of a connection between the service and the injury, disease or death, the claim must be dealt with in accordance with s.120(1). That is to say, the Commission must determine that the injury, disease or death was war caused "unless it is satisfied, beyond reasonable doubt, that there is no sufficient ground for making that determination". The use of the terms "the material" and "raise" strongly suggests that sub-s.(3) is not concerned with the proof or satisfaction of a claim but with whether there is some "material" which calls for a determination under s.120(1). The phrase "(i)n applying subsection (1) or (2)" (emphasis added) in s.120(3) also suggests that s.120(1) is the governing provision.

12. The relationship between s.120(1) and s.120(3) is analogous to the raising of the common law "defence" of provocation in a trial for murder in respect of which it has been said ((6) Mancini v. Director of Public Prosecutions (1942) AC 1, at p 12):
"it is not the duty of the judge to invite the jury to
speculate as to provocative incidents, of which there is no evidence and which cannot be reasonably inferred from the evidence. The duty of the jury to give the accused the benefit of the doubt is a duty which they should discharge having regard to the material before them, for it is on the evidence, and the evidence alone, that the prisoner is being tried." Likewise, it is the duty of the Commission under s.120 to decide the claim on the material before it and, unless there is material which raises a reasonable hypothesis connecting the operational service with the incapacity or death, there is nothing upon which the Commission can find that the incapacity or death was war caused within the meaning of s.120(1). But once the material raises such a hypothesis, the operation of s.120(3) is spent and the case falls to be determined in accordance with s.120(1). That is to say, the Commission must determine that the injury etc. was war caused unless it is satisfied beyond reasonable doubt that there is no sufficient ground for making the determination.

13. The Commission will be satisfied beyond reasonable doubt "that there is no sufficient ground for making (the) determination" if it is satisfied beyond reasonable doubt that it cannot accept the raised facts or so many of them as are necessary to support the hypothesis. Thus, if the Commission is satisfied beyond reasonable doubt that it cannot accept the raised facts because of the unreliability of the material which is claimed to support them or because of the superior reliability of other parts of the material before the Commission or because the raised facts depend on inferences which the Commission is satisfied cannot be drawn, the Commission will be satisfied that there is no sufficient ground for making the determination. But unless the Commission is satisfied beyond reasonable doubt that there is no sufficient ground for the factual foundation of the hypothesis, the claim must succeed; we cannot conceive of a case where, for the purpose of s.120(3), the hypothesis is reasonable having regard to the raised facts, yet the Commission could be satisfied, "beyond reasonable doubt, that there is no sufficient ground for making the determination" even though the raised facts are not disproved. Indeed, once there is sufficient factual material to point to a reasonable hypothesis connecting the injury etc. with the operational service, it seems convenient simply to treat the case as governed by the application of s.120(1). If that is done, the claim will succeed unless the Commission is satisfied beyond reasonable doubt that the factual foundation upon which the hypothesis can operate does not exist ((7) cf. Barca v. The Queen (1975) 133 CLR 82, at p 105).
The evidence before the Tribunal

14. Before the Tribunal, the hypothesis that essential hypertension can be caused or contributed to by stress was supported by the evidence of Dr Miller who regarded a paper to this effect, sponsored by the National Heart Foundation, as "authoritative". His opinion was supported by Dr Schiller who relied on the published opinions of a number of medical researchers.

15. However, Professor O'Rourke, who gave evidence for the Commission, claimed that there was no credible link between the veteran's war service and his hypertension and that a hypothesis linking the two was fanciful. In his evidence, he appears to have accepted that, although there was a clear relationship between stress and a temporary rise in blood pressure, there was no evidence that this led to a sustained rise in blood pressure. Professor O'Rourke said that severe anxiety in the veteran had developed in the absence of hypertension and that the later severe hypertension of the veteran had developed in the absence of anxiety. He thought that factors such as predisposition and age accounted for the development of the veteran's hypertension. His evidence was supported by a report of Dr Brender which stated that the relevant medical literature did not suggest "that there is a causal relationship between psychiatric illnesses, such as anxiety state etc., and essential hypertension". Dr Brender expressed the opinion that stress is not a cause of essential hypertension in humans.

16. As will appear, the extent to which the learned Deputy President who constituted the Tribunal accepted the evidence of Professor O'Rourke and Dr Brender is not clear. But he expressly accepted parts of the written and oral evidence of Dr Freeman, who gave evidence for the Commission. The Deputy President said:
"In his report, Exhibit 3, Dr Freeman said: 'The question
of whether an anxiety state or stress can cause and lead to sustained hypertension can be looked at from two points of view. The first is the clinical one wherein large numbers of patients are followed for long periods of time and are subject to study by various analytical means and the second is to rely heavily on laboratory experiments and hypothetical constructs whereby, as Dr Schiller suggests, adrenalin and nor-adrenalin in response to anxiety or stress can lead to permanent elevation of blood pressure. As a clinical cardiologist clinition (sic) with 45 years of medical experience, my view is that the former approach is the most effective in determining the response of man in contrast to animals or experimental data in determining the effect of stress or anxiety (sic) blood pressure and most of the studies which I have quoted in my report of 23/8/88 are clinical studies which on balance did not find a nexus between anxiety, stress or psychological factors and the onset or progression of essential hypertension. It must be admitted that despite intense research into this problem, no entirely satisfactory cause has been determined for essential hypertension, beyond the association with a strong genetic element, an increase in body mass index and alcoholism.'

17. I accept Dr Freeman's statements as quoted above. It seems to me that ten clinical studies are worth one hundred paper experiments, and that experiments on animals have little weight compared to observed clinical effects in human beings. In his oral evidence Dr Freeman also added that whereas the hypothesis of stress as being related to essential hypertension was in vogue in the past, and was held, and still is held, by some respectable medical practitioners, modern studies have discounted that view and he preferred the works of Professor Ferguson and Frommer, a study of numerous government employees, the work of Biddell Thomas, a study of 1200 medical students and of Crump in 1979. He also said Brown, who is very esteemed, did not find a rise in levels in mild hypertensives.

18. As I accept Dr Freeman's views of the paper studies, which form the basis of the views of Drs Schindler (sic) and Miller, and because I prefer Dr Freeman's view that clinical observation outweighs paper studies, animal experiments and retrospective surveys, I am satisfied that after consideration of the whole of the material before me that that material does not raise a reasonable hypothesis connecting the veteran's essential hypertension with the admittedly war-caused condition of stress from which he has suffered, and still suffers."

19. The learned Deputy President also said that he accepted "as more probable than the contrary views expressed by the pro-stress papers" the view which he attributed to Professor O'Rourke, i.e. that, although there was a clear relation between mental and emotional stress and a temporary rise in blood pressure, there was no evidence that this led to a sustained rise.

20. In conclusion, the Deputy President said: "The evidence of Dr Freeman and of Professor O'Rourke satisfies

me that although the hypothesis of stress as contributing to the onset of essential hypertension has been advanced in a number of papers, that hypothesis is not reasonably based. That being so, and however well respected Drs Schiller and Miller may be in their profession, I am required by the terms of s.120(3) of the Act to be satisfied beyond reasonable doubt that there is no sufficient ground for determining that the veteran's essential hypertension was war-caused. It is a matter of regret for me that the decision of disputed matters between well respected physicians is left to a layman such as myself, who has no expertise in medical matters."

The Federal Court

21. All members of the Federal Court agreed that the Deputy President had not clearly identified the precise basis on which he rejected the appellant's claim. Wilcox J., who allowed the appeal at first instance, rejected the submission of counsel for the appellant that the Deputy President had erroneously sought to determine the factual correctness instead of the reasonableness of the hypothesis put forward on behalf of the appellant. However, his Honour concluded that the evidence of Dr Freeman which the Deputy President had accepted was "incapable of establishing the conclusion which he reached". His Honour said:
"But giving full weight to all of that evidence, it does no
more than indicate that Dr Freeman preferred the view that there was no relationship. He did not assert that there was no link, or that there could be no link. It would have been difficult for him to do this, given his admission that 'no entirely satisfactory cause has been determined for essential hypertension'." His Honour also held that the Tribunal had erred in failing to deal with an alternative case advanced by the veteran which claimed a relationship between war-caused alcoholism and his hypertension. Wilcox J. set aside the decision and remitted the matter to the Tribunal for a rehearing.

22. In the Full Court, Morling and Neaves JJ. agreed with Wilcox J. that the Deputy President had not "sought to determine the factual correctness of the hypothesis" although they said that there were some passages in the reasons "which, looked at in isolation, afford some support for (that) view". They also agreed with his Honour that the matter had to be remitted to the Tribunal because it had failed to deal with the alternative case of the veteran. However, their Honours were unable to agree with Wilcox J. that the evidence referred to in the reasons of the Tribunal was not capable of establishing the conclusion which it reached although they felt "bound to say there is much to be said in support of the conclusion reached by Wilcox J. on this issue". It is implicit in their Honours' reasons that they thought that the Tribunal had decided the case on the whole of the material and not on the quoted parts of Dr Freeman's report. Davies J. agreed with Morling and Neaves JJ. that the evidence which the Tribunal accepted supported its conclusion and that the Tribunal had erred in not considering the alternative case of the veteran. But his Honour found it "difficult to determine what the Tribunal required of a reasonable hypothesis". Accordingly, he held that the matter should be remitted to the Tribunal for a rehearing generally. By majority, the Full Court ordered that "the matter be remitted to the Tribunal to determine whether the material before it raises a reasonable hypothesis connecting the respondent's condition of hypertension with his consumption of alcohol and, consequently, with his war service".
The case should be reheard generally

23. It will be apparent from what we have said concerning the construction of s.120 that the order of the Full Court must be set aside on technical grounds. On that construction, the Tribunal would not necessarily dispose of the case by determining whether the material raised a reasonable hypothesis connecting the veteran's condition of hypertension with his consumption of alcohol. If the Tribunal answered that question in the affirmative, a further question would arise as to whether the material disproved the factual basis of that hypothesis beyond reasonable doubt. The order of the Full Court must therefore be set aside. The real question is whether the case should be reheard generally or only as to the alternative case with which the Tribunal failed to deal. In our opinion, it should be reheard generally.

24. We agree with Wilcox J. that, if the decision of the Deputy President was based on "Dr Freeman's statements as quoted above", it was not supported by those statements. All that Dr Freeman said in the quoted statements was that he found the clinical study to be:
"the most effective in determining the response of man in
contrast to animals or experimental data in determining the effect of stress or anxiety (sic) blood pressure and most of the studies which I have quoted ... are clinical studies which on balance did not find a nexus between anxiety, stress or psychological factors and the onset or progression of essential hypertension". However, we are not convinced that the Deputy President relied only on those statements as the basis of his decision.

25. When the reasons of the Deputy President are read as a whole, it is strongly arguable that he relied on other parts of the material, as well as the statements of Dr Freeman, to reach his decision. The Deputy President said, for example, that he accepted the comments of Professor O'Rourke "as more probable than the contrary views expressed by the pro-stress papers". He also said that the evidence of Dr Freeman and Professor O'Rourke had satisfied him that "although the hypothesis of stress as contributing to the onset of essential hypertension has been advanced in a number of papers, that hypothesis is not reasonably based". On the other hand, earlier in his reasons the Deputy President had said that it was because he accepted Dr Freeman's views of the paper studies which formed the basis of the opinions of Dr Miller and Dr Schiller and because he preferred Dr Freeman's views that clinical observation outweighs paper studies, animal experiments and retrospective surveys that he was "satisfied that after consideration of the whole of the material before me that the material (did) not raise a reasonable hypothesis". Although this passage may mean, as Wilcox J. held, that the decision of the Tribunal was based on the "statements" of Dr Freeman, it may also mean that the material as a whole had persuaded the Deputy President of the unreasonableness of the hypothesis put forward on behalf of the veteran because acceptance of Dr Freeman's view had undermined the basis of the opinions of Dr Miller and Dr Schiller. It is not easy to be confident as to what was the precise basis of the Tribunal's decision.

26. Moreover, ascertaining the basis of the decision is rendered harder by uncertainty as to what the Deputy President meant in other parts of his reasons. Like Davies J., we are of the opinion that "it is difficult to determine what the Tribunal required of a reasonable hypothesis". The Deputy President did not say that he regarded the hypothesis advanced on behalf of the appellant as unreal, tenuous or fanciful. Nor, as Davies J. pointed out, did the Deputy President expressly say that he was satisfied beyond reasonable doubt that the hypothesis was invalid. Significantly, he said that he accepted the comments of Professor O'Rourke "as more probable than the contrary views expressed by the pro-stress papers" and then later said that the "evidence of Dr Freeman and of Professor O'Rourke" had satisfied him that the hypothesis was not reasonably based. These statements are capable of the construction that he really decided the case on the balance of probabilities. The statement that he regretted that he had to make "the decision of disputed matters between well respected physicians" also suggests that the Deputy President applied a construction of s.120 different from what we regard as the true construction of that provision.

27. While we are not persuaded that the decision of the Tribunal was based only on acceptance of the evidence and reports of Dr Freeman, we are not persuaded that Wilcox J. was wrong in so holding. It follows that we cannot accept the construction which the Full Court put on those reasons: they are too ambiguous to allow a firm conclusion on the point.

28. In these circumstances, the appropriate order to make is that the matter be remitted to the Tribunal for a general rehearing. The order of the Tribunal has to be set aside by reason of the failure to examine the alternative case of the veteran, and, having regard to the unsatisfactory nature of the reasons of the Tribunal, the interests of justice will best be served if there is a rehearing of the whole case.

29. A further reason for rehearing the whole case is that, although the precise basis of the Tribunal's decision is not clear, an examination of the evidence before the Tribunal supports the inference "that the tribunal (was) applying the wrong test or (was) not in reality satisfied of the requisite matters" ((8) Reg. v. Australian Stevedoring Industry Board; Ex parte Melbourne Stevedoring Co. Pty. Ltd. (1953) 88 CLR 100, at p 120). Whether the hypothesis of Dr Schiller and Dr Miller is right or wrong, it could hardly be said that it was fanciful, impossible, incredible, not tenable or too remote or too tenuous unless it was established that there was no temporal connection between the appellant's anxiety state and his hypertension. If the Tribunal had accepted the opinion of Professor O'Rourke that the later severe hypertension of the appellant developed in the absence of anxiety, the factual basis of the hypothesis of Dr Schiller and Dr Miller would collapse. But, except on that basis, it is not easy to see how it could be said that the material did not raise a reasonable hypothesis connecting the essential hypertension of the appellant with the circumstances of his particular service. The hypothesis was supported by two eminent practitioners who drew on scientific studies which championed the theory. It was also conceded that "some respectable medical practitioners" accept the connection between stress and essential hypertension. It is a connection which apparently also has the support of the National Heart Foundation. True it is that the weight of informed medical opinion is against the hypothesis. However, the cause of essential hypertension is still unknown. In these circumstances, a finding that the hypothesis was not reasonable, although a matter for the Tribunal, is surprising. The finding and the ambiguous nature of the Tribunal's reasons raise the inference that it applied the wrong test or was "not in reality satisfied of the requisite matters".

30. The appeal should be allowed. The matter should be remitted to the Tribunal to be reheard.

BRENNAN J. Mr Bushell made a claim under the Repatriation Act 1920 (Cth) for a disability pension for incapacity. It was refused by a Repatriation Board and by a Veterans' Review Board ("the Board"). Mr Bushell applied for a review of the decision of the Board by the Administrative Appeals Tribunal ("the A.A.T."). The first decision of the A.A.T. was set aside by the Federal Court and the matter ultimately came on for rehearing before the A.A.T. constituted by Mr Deputy President Bannon Q.C. (as he then was). It is common ground that the A.A.T. had to determine the matter pursuant to the provisions of the Veterans' Entitlements Act 1986 (Cth) ("the Act") which repealed the Repatriation Act and substituted its own provisions for those which previously regulated veterans' pension entitlements. Mr Bushell's claim is taken to be a claim made under s.14 of the Act for a pension under s.13. Section 13 creates in the Commonwealth a liability, inter alia, to pay a pension to a veteran who "has become incapacitated from a war-caused injury or a war-caused disease". The terms "war-caused injury" and "war-caused disease" are defined for the purposes of the Act by s.9. It is not necessary to set out the whole of that provision; it is sufficient to note that the definitions it contains prescribe either a causal or temporal connection between the relevant morbid condition suffered by a veteran and "operational service" or "eligible war service". Those terms are themselves defined by ss.6 and 7 respectively. An entitlement to a pension under s.13 thus depends upon three matters of fact: the veteran's operational service or eligible war service, the veteran's morbid condition and the connection between the two.

2. When a veteran makes a claim for a pension under Pt II of the Act (which includes ss.13 and 14), it is the duty of the Secretary of the Department of Veterans' Affairs to investigate the claim and to submit the claim together with any material assembled by the Department and any evidence furnished by the claimant to the Repatriation Commission ("the Commission"): s.17. The Commission determines the claim at first instance and is empowered to summon persons other than claimants to appear to give evidence and produce documents, to request the Secretary or a claimant to furnish material and to request a claimant to attend "for a discussion of the claim": s.32. The Commission's decision may be reviewed in turn by the Board and then by the A.A.T. Both the Board (see ss.151 and 152) and the A.A.T. (Administrative Appeals Tribunal Act 1975 (Cth), ss.37(2), 38 and 40) have powers to compel the production of material for the purposes of the review. Each of these reviews is an administrative procedure in which the finding of material facts is governed by the provisions of s.120 the relevant parts of which read::
"(1) Where a claim under Part II for a pension in respect of
the incapacity from injury or disease of a veteran, or of the death of a veteran, relates to the operational service rendered by the veteran, the Commission shall determine that the injury was a war-caused injury, that the disease was a war-caused disease or that the death of the veteran was war-caused, as the case may be, unless it is satisfied, beyond reasonable doubt, that there is no sufficient ground for making that determination. ... (3) In applying subsection (1) or (2) in respect of the incapacity of a person from injury or disease, or in respect of the death of a person, related to service rendered by the person, the Commission shall be satisfied, beyond reasonable doubt, that there is no sufficient ground for determining: (a) that the injury was a war-caused injury or a defence-caused injury; (b) that the disease was a war-caused disease or a defence-caused disease; or (c) that the death was war-caused or defence-caused; as the case may be, if the Commission, after consideration of the whole of the material before it, is of the opinion that the material before it does not raise a reasonable hypothesis connecting the injury, disease or death with the circumstances of the particular service rendered by the person. (4) Except in making a determination to which subsection (1) or (2) applies, the Commission shall, in making any determination or decision in respect of a matter arising under this Act or the regulations, including the assessment or re-assessment of the rate of a pension granted under Part II or Part IV, decide the matter to its reasonable satisfaction. (5) Nothing in the provisions of this section, or in any other provision of this Act, shall entitle the Commission to presume that: (a) an injury suffered by a person is a war-caused injury or a defence-caused injury; (b) a disease contracted by a person is a war-caused disease or a defence-caused disease; (c) the death of a person is war-caused or defence-caused; or (d) a claimant or applicant is entitled to be granted a pension, allowance or other benefit under this Act. (6) Nothing in the provisions of this section, or in any other provision of this Act, shall be taken to impose on: (a) a claimant or applicant for a pension or increased pension, or for an allowance or other benefit, under this Act; or (b) the Commonwealth, the Department or any other person in relation to such a claim or application; any onus of proving any matter that is, or might be, relevant to the determination of the claim or application." Section 120 governed the review by the A.A.T. of the decision of the Board on Mr Bushell's claim.

3. This section is not concerned with an onus of proof. Sub-section (6) says so expressly. It is concerned with a standard of satisfaction to which the administrative decision-maker must attain in finding the relevant facts, and it directs the decision-maker to act on the material before the Commission, the Board or the A.A.T., as the case may be. Proceedings before the A.A.T. may sometimes appear to be adversarial when the Commission chooses to appear to defend its decision or to test a claimant's case but in substance the review is inquisitorial. Each of the Commission, the Board and the A.A.T. is an administrative decision-maker, under a duty to arrive at the correct or preferable decision in the case before it according to the material before it. If the material is inadequate, the Commission, the Board or the A.A.T. may request or itself compel the production of further material. The notion of onus of proof, which plays so important a part in fact-finding in adversarial proceedings before judicial tribunals, has no part to play in these administrative proceedings. Nor does s.120 create any presumption which has to be dispelled by the material before the decision-maker. In a case to which sub-s.(1) relates, however, the making of a finding on the material before the decision-maker is governed by sub-ss.(1) and (3). Sub-section (1) is a special provision governing claims by veterans who have rendered "operational service"; sub-s.(3) governs those claims and claims under Pt IV in respect of members of the Forces who have been engaged in peace-keeping service or hazardous service.

4. Section 120 was introduced in order to reverse the decision of this Court in Repatriation Commission v. O'Brien ((9) (1985) 155 CLR 422; Senate, Parliamentary Debates (Hansard), 13 November 1985, at p 2106), but s.120 must be construed according to its own terms rather than by reference to constructions placed on its statutory predecessor. Sub-section (1) governs the finding of each of the relevant facts on which entitlement depends: the circumstances of the veteran's operational service, the veteran's morbid condition and, relevantly, the causal connection between the two: "a reasonable hypothesis connecting the injury, disease or death with the circumstances of the particular service rendered by the person". Sub-section (3) contains a particular provision relating to the last of those issues. Sub-section (3) is not directed either to the morbid condition of the veteran or to the circumstances of the veteran's operational service, but solely to the hypothesis connecting the two. Unless the material before the decision-maker, unaffected by any notion of onus of proof or by any presumption, raises a reasonable hypothesis of a causal connection between the morbid condition and the veteran's operational service, the decision-maker is directed to form the relevant negative conclusion specified in par.(a), (b) or (c). I shall return presently to discuss what is meant by a "reasonable hypothesis" in the context of sub-s.(3), but it is clear that any reasonable hypothesis raised by the material must relate to the circumstances of the instant case, that is to say, it must relate to the morbid condition and to the circumstances of the veteran's operational service which the decision-maker finds to exist. The finding of these facts is governed solely by sub-s.(1).

5. If the material before the decision-maker satisfies the decision-maker beyond reasonable doubt that a morbid condition which might attract a pension does not exist or that the circumstances of operational service that might have a causal connection with the morbid condition did not occur, there is no purpose in considering the operation of sub-s.(3). But the decision-maker cannot be satisfied that the condition does not exist or that the circumstances did not occur unless the material establishes those negative conclusions beyond reasonable doubt. There is no legal rule which governs the reaching of those conclusions. A negative conclusion on either of these issues may properly be reached in a particular case where there is no material tending to show that the morbid condition exists or that the possibly relevant circumstances of operational service occurred provided that, on the material before the decision-maker, it is reasonable to draw the negative inference from the absence of any material tending to show a positive conclusion. That is a proposition which cannot always be applied in adversarial litigation where there is an onus on one party or another to adduce evidence tending to prove a particular issue, but s.120 is structured on the expectation that a claim will be investigated by the Secretary, the Commission, the Board and the A.A.T. and that the relevant facts will be revealed by the investigation. There is no responsibility resting on the "parties" to the administrative proceeding to lay before the decision-maker any material in addition to the results of the Secretary's investigation ((10) Indeed, a claimant who requests an opportunity to discuss a claim with the Commission is permitted to do so only if the Commission "is of the opinion that the request is in all the circumstances reasonable": s.32(3).). In other words, an absence of material does not necessarily result in a negative conclusion: it may result in a request for further information, the summoning of a witness or the production of further documents. But if, at the end of the day, when all reasonable investigation has been completed and the parties have been given an opportunity to supplement the results of the investigation with whatever relevant material they may wish to lay before the decision-maker, there is no material tending to show that a particular morbid condition exists or that a relevant circumstance of operational service occurred, the decision-maker may be satisfied beyond reasonable doubt - if it be proper to draw the inference - that there is no sufficient ground for finding that a material morbid condition exists or that a relevant circumstance of operational service occurred. In the nature of things, that would be an exceptional case. The more usual case of difficulty occurs when there is material tending to show, and the decision-maker is prepared to determine, that a particular morbid condition exists and that a relevant circumstance of operational service occurred but the causal connection between the two is in contest. That is the case to which sub-s.(3) is directed.

6. The causal connection with which sub-s.(3) is concerned often depends, as in the present case, on a theory of medical science. Some theories assert and others deny a connection between a particular morbid condition and a postulated cause. The decision-maker is directed to determine from the material before it whether there is a "reasonable hypothesis" that the circumstances of operational service are connected with the veteran's morbid condition. Again, the absence of any material raising such an hypothesis may lead the decision-maker to seek further investigation of the claim. However, at the end of the day, unless the material raises such an hypothesis, the decision-maker must be satisfied beyond reasonable doubt that there is no causal connection. But sub-s.(3) goes no further than directing that conclusion when the material does not raise a "reasonable hypothesis". If the material does raise a reasonable hypothesis, sub-s.(3) does not operate and the ultimate determination of a causal connection must be made on the whole of the material pursuant to sub-s.(1).

7. However, in a case where a causal connection between the circumstances of operational service and a veteran's morbid condition is a matter of hypothesis only, the raising of a reasonable hypothesis by the evidence not only precludes the operation of sub-s.(3) but also will generally preclude a determination under sub-s.(1) that there is no causal connection. In such a case, where a decision-maker makes a determination under sub-s.(1) on the same material as that which led to a conclusion under sub-s.(3) that there is a "reasonable hypothesis" of connection, it would be impossible to conclude beyond reasonable doubt that there is no causal connection. Before a negative conclusion could be reached, the decision-maker would have to be satisfied beyond reasonable doubt of the existence of some further fact which destroys the applicability of the reasonable hypothesis of causal connection. In the present case, the question is whether the A.A.T. made a determination that there was no reasonable hypothesis in conformity with the directions contained in s.120.

8. The meaning of "reasonable hypothesis" was stated by the Board and subsequently adopted by the AA.T. in Re Dell and Repatriation Commission((11) (1986) 9 ALD 596, at p 615), and by a Full Court of the Federal Court in East v. Repatriation Commission((12) (1987) 16 FCR 517, at p 532). The Board said:
" A hypothesis may be conveniently defined as: 'proposition

made as basis for reasoning, without assumption of its truth; supposition made as starting point for further investigation from known facts; groundless assumption': The Concise Oxford Dictionary. ... The addition of the word 'reasonable' would however seem to imply that what is required is more than a mere hypothesis. In the opinion of the Board, to be reasonable, a hypothesis must possess some degree of acceptability or credibility - it must not be obviously fanciful, impossible, incredible or not tenable or too remote or too tenuous. For a reasonable hypothesis to be 'raised' by material before the Board, we think it must find some support in that material - that is, the material must point to, and not merely leave open, a hypothesis as a reasonable hypothesis."

9. The conception of a "reasonable hypothesis" was expounded by Beaumont J. in Repatriation Commission v. Webb((13) (1987) 76 ALR 131, at p 135):
" Thus the central question in the present case was to

determine whether the hypothesis advanced by the respondent as to the cause of his disease was 'reasonable' or not. It is hardly necessary to observe that the question whether an hypothesis is 'reasonable' is one thing; to determine whether, as a matter of professional opinion, that hypothesis represents the preferred view is a different matter: a number of opinions may be held by a number of experts in the field; each view may be reasonably held notwithstanding that they may lead to different conclusions. The point sought to be achieved by the introduction into s 120 of the notion of a 'reasonable' hypothesis is the distinction between a theory that is rationally based, on the one hand, and an opinion or view that is irrational, absurd or ridiculous, on the other. It is possible, especially as here, where the aetiology of the disease is unknown, to have more than one reasonable hypothesis advanced which suggest different causes of the disease. The exercise is not one of balancing or weighing the respective merits of a range of professional opinions. Rather, it is a case of determining whether the particular theory has a rational foundation."

I respectfully agree with the passages I have cited. The question that the A.A.T. had to decide pursuant to s.120(3) was whether the material before it raised a reasonable hypothesis in the sense discussed in those passages.

10. The material before the A.A.T. included expert evidence from four gentlemen whom Mr Deputy President Bannon described as "well respected medical practitioners", two of whom were called as witnesses on behalf of Mr Bushell, two on behalf of the Commission. Mr Deputy President Bannon noted that "the experts called in support of the application maintain that the hypothesis is reasonable, while those called on behalf of the respondent have a contrary opinion". Having considered the evidence given by these respected physicians, Mr Deputy President Bannon concluded: "The evidence of Dr Freeman and of Professor O'Rourke satisfies

me that although the hypothesis of stress as contributing to the onset of essential hypertension has been advanced in a number of papers, that hypothesis is not reasonably based. That being so, and however well respected Drs Schiller and Miller may be in their profession, I am required by the terms of s.120(3) of the Act to be satisfied beyond reasonable doubt that there is no sufficient ground for determining that the veteran's essential hypertension was war-caused. It is a matter of regret for me that the decision of disputed matters between well respected physicians is left to a layman such as myself, who has no expertise in medical matters."

11. Wilcox J. in the Federal Court was of the opinion that the A.A.T. had erred in the conclusion that the hypothesis advanced on behalf of Mr Bushell was unreasonable, set aside the decision of the A.A.T. and remitted the matter to the A.A.T. for rehearing. On further appeal to the Full Court, Morling and Neaves JJ. held that there was evidence before the A.A.T. on which it could find that the hypothesis of causal connection was unreasonable. The order made by Wilcox J. was varied to limit the rehearing to a question which their Honours held had not been determined by the A.A.T. Davies J., who accepted the view that there was evidence on which the A.A.T. could have found that the hypothesis of causal connection was unreasonable, nevertheless thought that it was "difficult to determine what the Tribunal required of a reasonable hypothesis". His Honour thought the matter should go back to the A.A.T. for a rehearing generally. In the course of his judgment, his Honour said:
" A reasonable hypothesis will ordinarily be established if
a responsible medical practitioner, speaking within the ambit of his expertise, and after considering the particular facts of the veteran's case, puts forward a theory of a likely, in the sense of a realistically possible, not fanciful, causal connection between war service and the veteran's disability. That being done, the s.120(1) standard of proof will apply. The veteran's claim may be dismissed if the decision-maker is satisfied beyond reasonable doubt on all the evidence that any necessary element of fact did not exist, or that the theory was, in the circumstances of the case completely untenable. See Webb v. Repatriation Commission((14) (1988) 78 ALR 696, at pp 699-700); Gilbert v. Repatriation Commission((15) (1989) 86 ALR 713, at pp 719-721)."

In my respectful opinion, that is the correct approach. The purpose of s.120(3) is to ensure that, though fashion in medical theories changes, veteran claimants who have had operational service should not be prejudiced so long as there is a reasonable hypothesis of connection favouring entitlement to a pension. It would be an exceptional case in which it would be right for the A.A.T., forming its own view of competing medical theories, to hold an hypothesis of connection favouring entitlement to be unreasonable, when the hypothesis is supported by "a responsible medical practitioner, speaking within the ambit of his expertise".

12. Although s.120(3) entrusts the determination of the issue of reasonableness to the decision-maker, the decision-maker is bound to have regard to its own want of scientific expertise in comparison with the expertise of a responsible medical practitioner who supports the reasonableness of an hypothesis favouring entitlement. It does not appear that that was the approach taken by the A.A.T. in this case where a "layman" purported to decide "disputed matters between well-respected physicians". It follows that, in my view, the order made by Wilcox J. should be restored. I would allow the appeal from the decision of the Full Court of the Federal Court, set that decision aside and in lieu thereof order that the appeal to that Court be dismissed.

TOOHEY J. The history of legislative attempts to provide a satisfactory formula for the determination of claims for service- related incapacities has not been a happy one. A glance at the index to the series, Administrative Law Decisions, under the heading "Veterans' affairs", gives some idea of the amount of litigation the relevant legislation has spawned.

2. Most of the problems have arisen through attempts to provide a scheme for veterans which is beneficial but which, at the same time, excludes claims that are fanciful. This accommodation has proved most difficult where the aetiology of a disease is unknown or uncertain. The most recent attempt at a solution is to be found in the Veterans' Entitlements Act 1986 (Cth) ("the Act"); it is that statute which has given rise to the present appeal.
The legislation

3. The provision which lies at the heart of this appeal is s.120 of the Act. In approaching the section, it is necessary to understand that the appellant's claim for a pension is under Pt II of the Act. So far as is relevant, s.120 reads:
"(1) Where a claim under Part II for a pension in respect of
the incapacity from injury or disease of a veteran, or of the death of a veteran, relates to the operational service rendered by the veteran, the Commission shall determine that the injury was a war-caused injury, that the disease was a war-caused disease or that the death of the veteran was war-caused, as the case may be, unless it is satisfied, beyond reasonable doubt, that there is no sufficient ground for making that determination. (2) ... (3) In applying subsection (1) or (2) in respect of the incapacity of a person from injury or disease, or in respect of the death of a person, related to service rendered by the person, the Commission shall be satisfied, beyond reasonable doubt, that there is no sufficient ground for determining: (a) that the injury was a war-caused injury or a defence-caused injury; (b) that the disease was a war-caused disease or a defence-caused disease; or (c) that the death was war-caused or defence-caused; as the case may be, if the Commission, after consideration of the whole of the material before it, is of the opinion that the material before it does not raise a reasonable hypothesis connecting the injury, disease or death with the circumstances of the particular service rendered by the person. (4) ... (5) ... (6) Nothing in the provisions of this section, or in any other provision of this Act, shall be taken to impose on: (a) a claimant or applicant for a pension or increased pension, or for an allowance or other benefit, under this Act; or (b) the Commonwealth, the Department or any other person in relation to such a claim or application; any onus of proving any matter that is, or might be, relevant to the determination of the claim or application."

4. It may be noted that the heading to s.120 is "Standard of proof". The section does mention onus of proof in sub-s.(6) but only by providing that nothing in the Act imposes on a claimant, the Commonwealth, the Department or "any other person" any onus of proving a relevant matter.

5. Sub-section (1) requires the Repatriation Commission, in the circumstances there mentioned, to determine that the disease in respect of which a claim is made was a war-caused disease, "unless it is satisfied, beyond reasonable doubt, that there is no sufficient ground for making that determination". Sub-section (3) is by way of amplification. It requires the Commission to be satisfied beyond reasonable doubt that, inter alia, the disease was a war-caused disease if, "after consideration of the whole of the material before it, it is of the opinion that the material before it does not raise a reasonable hypothesis connecting the ... disease ... with the circumstances of the particular service rendered by the person". I have said that sub-s.(3) is by way of amplification; that statement calls for explanation later in these reasons.
The facts

6. The appellant served in the Royal Australian Air Force from 30 June 1941 until 8 January 1946. For 12 months or so he was in combat areas in New Guinea; he spent a few months, towards the end of the war, at Morotai. While serving in combat areas the appellant was an operations-room clerk, working with the operations-room officer and the intelligence officer. Frequently he was sent as a member of an advance party into the forward area. This involved close proximity to the enemy, though not face-to-face combat. His operational headquarters were frequently bombed and occasionally strafed. The appellant said that he became intolerant after his tour in New Guinea and, in Australia, was outspoken with his superiors at having to perform seemingly pointless and time-wasting activities. He became short tempered, lost weight and suffered from a gastric problem which first manifested itself in New Guinea. Against that background, prior to his discharge the appellant sought psychiatric advice within the service and received psychiatric treatment in hospital. He suffered stress problems during his service and emotional problems at Morotai.

7. On 13 November 1945 the appellant was declared permanently unfit for duty because of "temperamental instability". The psychiatrist, whom he had previously consulted, gave him the robust advice to "keep away from doctors, avoid medication, and have a few beers every afternoon when I knocked off and to have them with people other than the people with whom I worked". The appellant seems to have followed this advice with fidelity. He drank about four middies of beer each afternoon until June 1985 when he cut down his intake following an acute myocardial infarct.

8. It was only in 1956, when the appellant needed a medical examination in relation to his driver's licence, that he attended a doctor for the first time after his discharge from the Air Force. Dr Bathgate's report of 11 May 1956 showed the appellant's blood pressure as 140/90. It seems that Dr Bathgate said nothing to the appellant about his blood pressure and he did not attend a doctor again until 27 December 1972. He was then suffering from gout. His blood pressure was 160/120. Soon afterwards the appellant began anti-hypertensive medication. Some forms of that medication worsened nightmares he had experienced during and since the war.

9. The appellant complained that since discharge he had frequently experienced indigestion, stomach upsets and diarrhoea (the latter condition having developed during the war). He was a heavy smoker until he ceased smoking in 1953. His weight suddenly increased by two and a half stone (16 kg) but later dropped to about 13 stone (82 kg). This was still some two stone (13 kg) over his earlier weight.
The appellant's attempts to secure a pension

10. Although the appellant was discharged from the Air Force in January 1946 because of "temperamental instability", he did not apply for a service pension until 1982. That application was made under the provisions of the Repatriation Act 1920 (Cth) and, it seems, was on the ground that his "temperamental instability" had worsened since his discharge. Based on psychiatric advice, the appellant also claimed 100% of the general rate of pension for incapacity in respect of anxiety state as being service related. The Repatriation Commission considered the assessment of 100% excessive. Based on other psychiatric advice diagnosing the appellant's service-related condition as "anxiety neurosis", the Commission assessed the incapacity as 40% of the general rate. On 18 December 1985 the Veterans' Review Board affirmed that decision.

11. The appellant sought a review of the decision of the Veterans' Review Board by the Administrative Appeals Tribunal. On 14 August 1987 the Tribunal (Gallop J., Dr Renouf and Mrs Lewis) affirmed the decision of the Veterans' Review Board. The appellant appealed from the decision of the Tribunal to the Federal Court. The hearing before the Tribunal proceeded on the basis that the Act, which had by then come into existence, was the relevant Act. It has remained so.

12. In an ex tempore judgment, a Full Court of the Federal Court (Davies, Gummow and Foster JJ.) ordered: "(T)he matter is remitted to the Administrative Appeals Tribunal to be heard and decided again with or without the hearing of further evidence." The Full Court took this step because, as was conceded by the respondent, the Tribunal had applied the wrong test in determining whether the appellant had an anxiety state, attributable to war service, which contributed to hypertension. Before the Tribunal and thereafter, the debate was as to whether the appellant was suffering from essential hypertension because of war service.

13. The matter went back to the Administrative Appeals Tribunal, this time constituted by Deputy President Bannon Q.C. On 7 April 1989 Mr Bannon affirmed the decision under review. Once again the appellant appealed to the Federal Court. Wilcox J. allowed the appeal, set aside the decision of the Tribunal and ordered that "the matter be remitted to the Tribunal for further hearing and determination according to law". The appellant again appealed to the Federal Court. On 3 May 1991 a Full Court of the Federal Court (Morling and Neaves JJ., Davies J. dissenting) made an order in these terms:
"1. The decision of the Administrative Appeals Tribunal of 7

April 1989 be set aside and the matter be remitted to the Tribunal to determine whether the material before it raises a reasonable hypothesis connecting the respondent's condition of hypertension with his consumption of alcohol and, consequently, with his war service. 2. Otherwise the appeal be dismissed. 3. There be no order as to the costs of the appeal."

14. The appellant now appeals to this Court and he seeks the following orders: "That the appeal be allowed with costs.
That the orders of the Full Court be set aside, and in lieu therefore it be ordered that: i) The orders made on 13 August 1990 be varied by substituting for Order 2 an order that the decision of the Administrative Appeals Tribunal of 7 April 1989 be set aside, and in lieu thereof there be substituted a decision setting aside the decision of the Repatriation Commission of 23 November 1984 and remitting the matter for reconsideration by the Repatriation Commission in accordance with the direction that the veteran's claim for pension in respect of incapacity from hypertension be granted. ii) Otherwise the appeal be dismissed. iii) The appellant, the Repatriation Commission, pay the respondent's costs of the appeal."

15. The order of the Full Court of 3 May 1991 calls for some explanation in order to understand the arguments before this Court. Then it is necessary to turn to the relevant legislation, noting however the very unsatisfactory state of affairs that can produce such a prolixity of reviews and appeals.
The proceedings before the Tribunal and the Federal Court

16. Before Deputy President Bannon four medical practitioners gave evidence. It is apparent from their evidence that the origin of essential hypertension is much debated. It is unnecessary to refer to the medical evidence in detail. Dr Schiller and Dr Miller subscribed to the theory that stress causes or contributes to essential hypertension in predisposed people. On the other hand, Dr Freeman and Professor O'Rourke were of the view that there was no causal relationship between psychiatric illnesses such as anxiety state and hypertension. Indeed, in his report of 26 September 1988 Professor O'Rourke went so far as to describe the hypothesis linking war service and essential hypertension as "fanciful". In his report of 3 February 1989, Dr Freeman referred to clincial studies which, in his opinion, failed to find "a nexus between anxiety, stress or psychological factors and the onset or progression of essential hypertension".

17. It is important to see how the Tribunal dealt with the competing views expressed to it. Mr Bannon said that he accepted Dr Freeman's view because: "It seems to me that ten clinical studies are worth one hundred paper experiments". Mr Bannon referred to the oral evidence of Dr Freeman that "whereas the hypothesis of stress as being related to essential hypertension was in vogue in the past, and was held, and still is held, by some respectable medical practitioners, modern studies have discounted that view".

18. In referring to Professor O'Rourke, Mr Bannon observed: "His comments ... I accept as more probable than the contrary views expressed by the pro-stress papers". The Tribunal's analysis of the medical opinions concludes in this way:
"The evidence of Dr Freeman and of Professor O'Rourke
satisfies me that although the hypothesis of stress as contributing to the onset of essential hypertension has been advanced in a number of papers, that hypothesis is not reasonably based. That being so, and however well respected Drs Schiller and Miller may be in their profession, I am required by the terms of s.120(3) of the Act to be satisfied beyond reasonable doubt that there is no sufficient ground for determining that the veteran's essential hypertension was war-caused. It is a matter of regret for me that the decision of disputed matters between well respected physicians is left to a layman such as myself, who has no expertise in medical matters."

19. The Tribunal's approach was attacked by the appellant on the ground that it involved an examination of competing hypotheses and the preference for one hypothesis over another. Certainly, that is not what s.120 requires to be done. As Beaumont J. pointed out in Repatriation Commission v. Webb((16) (1987) 76 ALR 131, at p 135):
"It is hardly necessary to observe that the question whether

an hypothesis is 'reasonable' is one thing; to determine whether, as a matter of professional opinion, that hypothesis represents the preferred view is a different matter: a number of opinions may be held by a number of experts in the field; each view may be reasonably held notwithstanding that they may lead to different conclusions."

Although Beaumont J.'s decision was reversed on appeal((17) Webb v. Repatriation Commission (1988) 78 ALR 696), I do not read the judgments of the Full Court (Davies, Morling and Foster JJ.) as expressing any disapproval of this passage.

20. In the instant case Wilcox J. was "not persuaded that Mr Bannon misunderstood the question to be determined". Rather, his Honour concluded, the Deputy President's error was:
"that the primary facts found by him were incapable of
supporting his ultimate conclusion. He did not find any facts which, as a matter of law, were capable of supporting the conclusion that the hypothesis advanced on behalf of the (present appellant) was unreasonable." However, his Honour considered that it was not appropriate for the Court to make an order in the appellant's favour because:

"there was other evidence before the Tribunal, upon which no findings were made. It is theoretically possible that this evidence does contain material upon which the Tribunal could properly find that the postulated hypothesis is not reasonable."

The matter had therefore to go back to the Tribunal for rehearing.

21. There was before the Court what Wilcox J. described as "a subsidiary argument put on behalf of the applicant". It was common ground that alcoholism and obesity could cause hypertension. Mr Bannon made no findings as to whether the appellant's alcoholism and obesity should be attributed to his war service. There was an issue between counsel as to whether this alternative case had been presented in final submissions to the Tribunal. Wilcox J. was satisfied that the present appellant had pressed the point and that the Tribunal erred in not making a ruling on that case.

22. In the Full Court, Morling and Neaves JJ. took a different view of the way in which the Tribunal reached its conclusion on the primary argument before it. They said((18) Repatriation Commission v. Bushell (1991) 23 ALD 13, at p 19):
" We are bound to say there is much to be said in support
of the conclusion reached by Wilcox J on this issue. But we have come to the conclusion from a perusal of all the evidence which was before Mr Bannon that there was sufficient material before him to enable him to reach the conclusion that it did not raise a reasonable hypothesis connecting the veteran's essential hypertension with his war service." Their Honours agreed with Wilcox J. that the alternative case had been put and had not been dealt with. This explains the form of the order made by the Full Court, in particular the limited basis on which the matter was to go back to the Tribunal.

23. Davies J. would have dismissed the appeal. While his Honour agreed with Morling and Neaves JJ. that there was evidence before the Tribunal on which it could have found that "the theory of a connection between stress and hypertension was not a reasonable hypothesis", he said that it was "difficult to determine what the Tribunal required of a reasonable hypothesis"((19) ibid., at p 16.). Therefore, as Wilcox J. ordered, the matter should go back to the Tribunal generally.

24. It is unnecessary to refer to the grounds of appeal to this Court in any detail. Essentially the appellant contends that the majority in the Full Court should have held that the Tribunal misconceived the task required of it by s.120 and that, on a proper understanding of that task, it was not open to the Tribunal to reach the conclusion that no reasonable hypothesis was raised connecting the appellant's hypertension with his war service.
Section 120

25. It would be profitless to trace the history of decisions relating to the Act and its predecessor as amended from time to time. The focus must be on s.120 of the Act, including the relationship between sub-s.(1) on the one hand and sub-ss.(3) and (6) on the other. As to sub-s.(3), a Full Court of the Federal Court recently said that((20) Repatriation Commission v. Whetton (1991) 31 FCR 513, at p 514) "(i)t is accepted that the genesis of subs (3) was the dissenting judgment of Brennan J in Repatriation Commission v. O'Brien((21) (1985) 155 CLR 422.)." In O'Brien((22) ibid., at p 438) Brennan J. observed of the legislation then in force: "If the facts thus ascertained support a reasonable hypothesis

that the claimant is entitled to a benefit under the eligibility provisions of the Act, the Board or the Commission must determine to grant the claim. If a reasonable hypothesis of entitlement arises on some of those facts, the Board or Commission must determine to grant the claim unless other facts dispel the hypothesis beyond reasonable doubt. If the Board or Commission is satisfied that no reasonable hypothesis of entitlement is supported by the facts or that any such reasonable hypothesis is dispelled beyond reasonable doubt, the Board or Commission should reject the claim. Where, on the whole of the material no reasonable hypothesis of entitlement arises, there are 'insufficient grounds for granting the claim'."

26. If s.120(1) stood on its own, there might be little difficulty in the application of the section. While the sub-section does not in terms impose an onus upon any party, its practical operation is to ensure that a claim is granted unless the Commission is satisfied, according to the criminal standard of proof, that there is no sufficient ground for concluding (as in the present case) that the disease in respect of which a pension is sought is a war-caused disease.

27. Some difficulty arises because of the provisions of sub-s.(3) and, to a lesser extent, of sub-s.(6). The former sub-section is, in my view, epexegetical of sub-s.(1). It dictates that in the circumstances there mentioned the Commission "shall be satisfied beyond reasonable doubt" that there is no sufficient ground for making a determination favourable to the claimant. In the circumstances of the present case, sub-s.(3) requires that if the Commission, on the whole of the material before it, is of opinion that the material does not raise a reasonable hypothesis connecting the disease (essential hypertension) with the service of the appellant (in New Guinea and Morotai) - I leave aside the question of alcoholism at this stage - the Commission must be satisfied in terms of sub-s.(1) that there is no sufficient ground for making the determination sought by the appellant.

28. The scheme of s.120 is such that the Commission inevitably turns its attention first to sub-s.(3). In doing so, it does not proceed on the basis of any onus, whether as to "reasonable hypothesis" or otherwise. That is a consequence of sub-s.(6). As Beaumont J. observed in Repatriation Commission v. Webb((23) (1987) 76 ALR , at p 135. This passage was not disapproved of by the Full Court in Webb v. Repatriation Commission, which reversed Beaumont J.'s decision on appeal): "But neither expressly nor by implication does s120, in any of
its provisions, require the Commission to rebut an hypothesis beyond reasonable doubt. Rather, the legislation proceeds upon the assumption that the circumstances will indicate whether or not the hypothesis advanced has a rational foundation. If such a foundation exists, a claimant will be entitled to pension. But neither the claimant nor the Commission bears the onus of establishing its rationality or its lack of rationality beyond reasonable doubt."

29. While sub-s.(3) is epexegetical of sub-s.(1), it is not exhaustively so. If the Commission is of the opinion that the material does raise a reasonable hypothesis, it may nevertheless refuse a pension if it is satisfied that there is no sufficient ground for making a favourable determination. Even though sub-s.(3) itself has not led to a rejection of a claim, the claim may be dismissed if, in the words of Davies J.((24) Repatriation Commission v. Bushell (1991) 23 ALD , at p 15.) in the present case, "the decision-maker is satisfied beyond reasonable doubt on all the evidence that any necessary element of fact did not exist, or that the theory was, in the circumstances of the case completely untenable". It may be, for instance, that the Commission is satisfied beyond reasonable doubt that, on the facts, an applicant did not come by the injury or the disease in the manner claimed. The claim will then be dismissed. But ordinarily, if the Commission is not of the opinion identified in sub-s.(3), a claim for a pension will succeed.
The Tribunal's decision

30. It is apparent from the judgment of Wilcox J. that he would have disposed of the appeal by making a determination in favour of the present appellant, except that it was "theoretically possible that (the evidence before the Tribunal upon which no findings were made) does contain material upon which the Tribunal could properly find that the postulated hypothesis is not reasonable". The postulated hypothesis is to be found in this passage from his Honour's judgment: "The primary case which was advanced to Mr Bannon was that the (appellant) suffered from essential hypertension and that there existed a reasonable hypothesis that this condition was caused by his war service."

31. What is meant, in the context of s.120, by "hypothesis", particularly "reasonable hypothesis"? In East v. Repatriation Commission ((25) (1987) 74 ALR 518, at p 534) a Full court of the Federal Court (Jenkinson, Neaves and Wilcox JJ.) discussed these questions and concluded:
" A reasonable hypothesis requies more than a possibliity,
not fanciful or unreal, consistent with the known facts. It is an hypothesis pointed to by te facts, even though not proved upon the balance of probabilities." The Concice Oxford Dictionary ((26) 8th ed. (1990), p 582) defines hypothesis as "a proposition made as a basis for reasoning, without the assumption of its truth; a supposition made as a starting-point for further investigation from known facts; a groundless assumption". The Macquarie Concise Dictionary((27) 2nd ed. (1988), p 473) speaks of "a proposition ... proposed as an explanation for the occurrence of some specified group of phenomena, either asserted merely as a provisional conjecture to guide investigation ... or accepted as highly probable in the light of established facts".

32. Before the Tribunal were four medical witnesses whom Mr Bannon described as "well respected medical practitioners". Dr Schiller expressed the view in his report of 10 October 1988 that "there is a reasonable theory that the claimed incapacity of essential hypertension is causally related to the (appellant's) temperamental instability (or anxiety state) which has been found to be attributable to his war service". Using other language, he repeated this opinion in his later report of 14 November 1988. Dr Miller furnished three reports and a paper. In the first report, dated 23 August 1988, he concluded: "I consider it a reasonable hypothesis therefore, that Mr Bushell's hypertension is causally related to his war service."

33. In any scientific field the distinction between opinion and hypothesis will often be a fine one. The justification for speaking of an hypothesis in relation to Drs Schiller and Miller is that both were recounting the relevant medical literature and commenting on the controversy in the medical profession, rather than expressing opinions based directly on their own experience of patients. The appellant contended that, given the qualifications and reputations of the two doctors and the material marshalled by them, it was not possible to say that the material before the Tribunal, including of course the opinions of Dr Freeman and Professor O'Rourke, permitted a conclusion that it did not raise a reasonable, that is not fanciful or unreal, hypothesis connecting the appellant's hypertension with his war service.

34. The argument has an obvious attraction, given the long history of this matter. But, as Davies J. observed((28) Repatriation Commission v. Bushell (1991) 23 ALD , at p 16):
" However, although it is clear that the tribunal thought
the hypothesis propounded was wrong, it is difficult to determine what the tribunal required of a reasonable hypothesis. The tribunal did not say, eg that the theory put forward in respect of Mr Bushell was fanciful. And, the tribunal did not expressly say that it was satisfied beyond reasonable doubt, on the whole of the evidence, that the hypothesis was unsound. There are indeed passages which could suggest that the tribunal entered into the arena of determining the validity of the hypothesis, and did so on the balance of probabilities, rather than determining, under s 120(3), whether the hypothesis was, as a theory or supposition, reasonable and pointed to by the facts." That observation of his Honour is, I think, unanswerable.

35. It follows that, while the decision of the majority in the Federal Court cannot stand and the appeal should be allowed, it is not possible for this Court to substitute its views for those of the decision-maker. The matter should be remitted to the Tribunal for rehearing in accordance with this judgment. "Matter" includes the issue of alcohol and obesity with which the Tribunal did not deal.

Orders

Appeal allowed with costs. Set aside the order of the Full court of the Federal Court and in lieu thereof order that the appeal to that Court be dismissed with costs.