(ii) The case at hand
51 In this case, the Tribunal was required to measure any hypothesis raised (or pointed to) by the material before it against the "template" of the PTSD SoP; and, if the hypothesis as raised (or pointed to) by the material fitted the template, then the Tribunal could accept the hypothesis as a reasonable hypothesis for the purposes of s 120(3) of the Act. If the hypothesis did not fit (because it did not contain the factors which the SoP set out as the minimum that must exist and be related to the veteran's service), then the hypothesis would not be reasonable for the purposes of s 120(3) and Mr Hill's claim would fail. That is, before Mr Hill could succeed on his pension claim for PTSD, the Tribunal had to be satisfied that the material before it raised a hypothesis of connection that was upheld by the PTSD SoP. (If the Tribunal was so satisfied, then it had to go on to consider whether it was satisfied beyond reasonable doubt that the factual basis upon which the hypothesis depended did not exist.)
52 Since the Commission did not dispute that Mr Hill was suffering from PTSD, the main issue before the Tribunal concerned the connection between Mr Hill's PTSD and his service. Mr Hill's position was that the material before the Tribunal raised a hypothesis that fitted cl 1 (a), (b), or (c) of the PTSD SoP because the material pointed to either his "experiencing a stressor" (as defined in cl 4 of the PTSD SoP) prior to the clinical onset or worsening of PTSD, or to his inability to obtain appropriate clinical management for the condition. Given that the Tribunal's rejection of the clinical worsening and clinical management hypotheses was unchallenged in this Court, the only possibility that fell for consideration by the primary judge was whether Mr Hill experienced a stressor prior to the clinical onset of PTSD. Before this hypothesis could warrant consideration under s 120(1) of the Act, the Tribunal had to be satisfied, amongst other things, that the material pointed to Mr Hill "witnessing" an event that involved "actual or threatened death", and that he responded with feelings involving "intense … helplessness or horror": see [9]-[10] and [23]-[24] above. The hypothesis put forward by Mr Hill was that he had witnessed the crash of the Sea Venom aircraft on 28 April 1966 and had seen a man's unsuccessful attempt to escape from the cockpit; that he had responded with a feeling of what could be properly described as intense helplessness or horror; and that his response was experienced prior to the clinical onset of his PTSD or the clinical worsening of it. As a mere hypothesis, this fitted one of the templates in the PTSD SoP: cf stage 3 of the Deledio approach set out at [50] above.
53 As already noted, the primary judge stated, at [31] of his reasons, that it was sufficient to satisfy ss 120(3) and 120A(3) of the Act that the hypothesis relied on by Mr Hill fitted the SoP in this way. As the authorities show, however, in order to satisfy ss 120(3) and 120A(3) of the Act, there must be more than a hypothesis of connection that is consistent with the relevant SoP. In order to satisfy these provisions, the material must "raise" or "point to" such a hypothesis and this hypothesis, as raised or pointed to by the material, must fit the relevant SoP. Although the terms of [31] of his Honour's reasons may signify error, we doubt that his Honour in truth failed to appreciate this latter requirement. Rather, as we see it, his Honour was focussing on another aspect of the matter (as to which, see below).
54 As already noted, the authorities have made the position with regard to ss 120(3) and 120A(3) of the Act clear enough. In Repatriation Commission v Bey (1997) 79 FCR 364 (which did not involve s 120A(3)), the Full Court reiterated earlier observations in East (at 531-32) and in Bushell (at 414) when it said at 372-3:
A 'reasonable hypothesis' involves more than a mere possibility. It is a hypothesis pointed to by the facts, even though not proved upon the balance of probabilities.
If an essential element of a hypothesis is not raised (or pointed to) by the material before the decision-maker, then the hypothesis is not raised by that material: cf East at 533.
55 Where s 120A(3) of the Act applies to a claim and there is a relevant SoP in force, whether or not an element is essential to a hypothesis will depend upon the terms of the SoP. As Goldberg J said in Repatriation Commission v McKenna (1998) 52 ALD 72 at 80:
For the purposes of s 120A(3) of the Act the hypothesis which has to be upheld by the Statement of Principles is the hypothesis which connects the disease suffered by a veteran with the circumstances of his service. So stated, the hypothesis has to point to a connection which starts with the disease in respect of which the application is made and ends with the service. That connection will comprise a number of links or factors each of which must be upheld by a Statement of Principles. … .
On appeal, the Full Court approved these propositions: see McKenna v Repatriation Commission (1999) 86 FCR 144 at 150-1. Put another way, a hypothesis connecting a disease with war service will only be reasonable if the material that raises it includes all of the essential elements prescribed by the SoP: see Deledio v Repatriation Commission at 274-275, Repatriation Commission v Gosewinckel (1999) 59 ALD 690 at 704 per Weinberg J, and Connors v Repatriation Commission (2000) 59 ALD 61 at 68-70.
56 Counsel for Mr Hill referred to Byrnes at 569-70 and Repatriation Commission v Stares (1996) 66 FCR 594 ("Stares") in support of the proposition that, in some cases, a hypothesis may assume the occurrence of certain facts and that the making of the assumption does not necessarily render the hypothesis unreasonable. This was the position prior to the introduction of ss 120A and 196B: see Stares at 601. For example, in Byrnes at CLR 570, the High Court held that:
[T]he appellant's hypothesis is not unreasonable simply because it assumes that the appellant sustained a severe injury when he dived into a swimming pool in Townsville, notwithstanding that the materials before the Commission did not reveal the extent of the injury which he then suffered.
Section 120A did not, however, apply to the claims made in Byrnes or Stares.
57 Whatever the situation may have been in relation to claims before 1 June 1994, the effect of s 120A(3) (where there is an SoP under s 196B(2)) is that a hypothesis is reasonable only if it is upheld by the SoP. Pursuant to s 196B(2), the SoP must set out "the factors that must as a minimum exist" and "which of those factors must be related to service". The result is that, where it applies, the SoP prescribes the essential content of what is a reasonable hypothesis, for s 120(3) purposes, capable of connecting the particular kind of injury, disease or death with the circumstances of a veteran's particular service. In order to satisfy ss 120(3) and 120A(3), a hypothesis relied on by a veteran to support a pension claim must be supported by material pointing to each element that the SoP makes essential for the hypothesis to be reasonable.
58 In order for Mr Hill to succeed, the hypothesis raised by the material before the Tribunal had to fit the template set out in the PTSD SoP. Mr Hill relied (and continues to rely) on a template that included the elements set out in cl 1(a) of the SoP (namely, that he experienced a stressor (as defined in cl 4) prior to the clinical onset of PTSD). In Mr Hill's case, "experiencing a stressor" was an essential ingredient of the hypothesis connecting PTSD with his war service. Amongst other things, this ingredient required a response to the witnessing of a particular kind of event that involved "intense fear, helplessness or horror". In consequence, in order to satisfy ss 120(3) and 120A(3), the material before the Tribunal had to point to a response of this kind. A question for the Tribunal was, therefore, whether the material before it raised (or pointed to) the witnessing by Mr Hill of an event of the kind described in par (a) of the definition of "experiencing a stressor", and his responding by emotions of the kind referred to in par (b) of the definition. The Tribunal apparently found that there was material pointing to Mr Hill's witnessing of an event of the kind described in par (a) of this definition, but not to his responding in the manner required by par (b). But for one matter, this approach would conform to the requirements of ss 120(3) and 120A(3) of the Act.
59 Plainly enough, before making a finding of this kind, the Tribunal must consider all the material before it. Having done so, the question whether the material raises or points to a relevant hypothesis of connection is essentially a matter for the Tribunal. As the primary judge emphasised, proof of facts is not in issue at this stage: Byrnes at 571 and Deledio at 97-98. The Tribunal may conclude that the material does not raise or point to a hypothesis that fits the template of a relevant SoP and that the hypothesis cannot, therefore, be accepted as reasonable. This decision cannot be the subject of an appeal under s 44(1) of the Administrative Appeals Tribunal Act 1975 ("AAT Act"), unless, in making it, the Tribunal has acted otherwise than in accordance with the law. If a tribunal falls into an error of law "which causes it to identify a wrong issue, to ask itself a wrong question, to ignore relevant material, to rely on irrelevant material or, at least in some circumstances, to make an erroneous finding or to reach a mistaken conclusion, and the tribunal's exercise or purported exercise of power is thereby affected, it exceeds its authority or powers": see Craig v State of South Australia (1995) 184 CLR 163 at 179. An error of law of this kind may support an appeal under s 44 of the AAT Act on a question of law: cf The Hospital Benefit Fund of Western Australia Inc v Minister for Health, Housing and Community Services (1992) 39 FCR 225 at 231-232 per Wilcox, Burchett and French JJ.
60 The critical question in this appeal is whether the reasons of the Tribunal, when read as a whole, disclose an error of law of a relevant kind: cf Minister for Immigration and Ethnic Affairs v Wu Shan Liang (1996) 185 CLR 259 at 280-1 per Brennan CJ, Toohey, McHugh and Gummow JJ and 292 per Kirby J. Although the primary judge may have expressed the question a little differently at [31] and [34], his Honour held, in substance, that the Tribunal had either identified the wrong issue and asked itself the wrong question, or had regard to irrelevant considerations and ignored relevant considerations: cf Minister for Immigration and Multicultural Affairs v Yusuf (2001) 180 ALR 1 at [4] per Gleeson CJ,[83]-[84] per McHugh, Gummow and Hayne JJ and [38]-[44] per Gaudron J and the Notice of Appeal dated 20 December 2000, ground (f).
61 We agree with his Honour that, when read as a whole, the Tribunal's reasons disclose an error of law, although we would characterise the error differently. In the circumstances of this case, the Tribunal erred by identifying the wrong issues in considering whether the material before it fitted a template in the PTSD SoP. As the final sentence of [89] of its reasons illustrates, in this paragraph, the Tribunal was not turning its mind to cl 1 of the PTSD SoP and to "experiencing a stressor". Rather, in [89] to [93], the Tribunal was considering whether the material before it pointed to the elements of "post-traumatic stress disorder" as defined in cl 4 of the PTSD SoP. This inquiry was not the correct one. The inquiry would have been relevant if there had been a dispute before the Tribunal as to whether or not Mr Hill was actually suffering from PTSD. As already noted, however, there was no such dispute (see [52]). As counsel for the Commission observed on the hearing of this appeal, the matter proceeded in the Tribunal on the basis that Mr Hill's condition was not in issue. Quite plainly, the discussion at [89]-[93] of the Tribunal's reasons addressed the wrong issue or issues.
62 As noted already, the Commission in fact conceded that the Tribunal fell into error in this regard, but it submitted that the error was inconsequential. We reject this submission. We note, first, that ss 120(1) and (3) (together with s 120A(3)) are directed to the standard of proof for establishing a causal connection between, amongst other things, a veteran's disease and his war service, assuming the existence of the relevant condition: see Repatriation Commission v Cooke (1998) 160 ALR 17 at 20 and Gosewinckel at 72. These provisions do not require any consideration of the question whether the veteran in fact suffered from the disease.
63 It should be borne in mind that the issue whether a particular disease exists is governed by s 120(4) of the Act, not ss 120(1) and (3). That is, the issue whether or not a disease exists is to be decided to the reasonable satisfaction of the Commission: see Repatriation Commission v Cooke at 20 and Gosewinckel at [49]. In this case, the relevant question under ss 120(3) and 120A(3) was whether there was material pointing to a hypothesis that fitted the relevant template in the PTSD SoP. The primary judge was clearly correct when he said, at [31], that the Tribunal should not engage in a "fact finding exercise" at this stage.
64 The conclusion that was critical to the Tribunal's decision was stated at [93] of its reasons. This was that there was "no material pointing to Mr Hill's PTSD arising out of, or being attributable to the Sea Venom incident or event in his eligible war service" because the material did not point to Mr Hill's meeting all of the criteria required for a finding of PTSD. In reaching this conclusion, the Tribunal identified the wrong issues and asked itself the wrong question. Put another way, the Tribunal determined that there was no material pointing to a causal connection between Mr Hill's PTSD and war service by reference to the wrong matters (i.e., matters irrelevant in law).
65 Counsel for the Commission submitted that, notwithstanding the error, the fact was that, at [89] of its reasons, the Tribunal had expressly found that the material before it did not point to a response of intense fear, helplessness or horror (i.e., that Mr Hill had not "experienced a stressor" as required by the causation requirement). Accordingly, counsel for the Commission submitted that the Tribunal had discharged its task under ss 120(3) and 120A(3) of the Act and that Mr Hill's claim must fail. Hence, so counsel submitted, any error on the Tribunal's part was inconsequential.
66 As counsel for the Commission observed, the definition of "experiencing a stressor" was materially the same as par (a) of the definition of PTSD. Hence, if one ignored (wrongly) the differences between the inquiry about causal connection and about the existence of the disease, then one might conclude that a finding concerning par (a) of the definition of PTSD would also be a finding about "experiencing a stressor". This appears to have been the Tribunal's approach in this case. In this way, the finding in [89] apparently conformed to the requirements of ss 120(3) and 120A(3), notwithstanding that the Tribunal was mistakenly directing itself to an issue about the existence of the disease. (In entering upon an inquiry as to the existence of PTSD, the Tribunal would have been wrongly entering "upon the fact finding exercise" to which the primary judge referred.)
67 The Commission's submission, so it seems to us, tends to obscure the fundamental nature of the error made by the Tribunal in failing to address the issues to which the case before it actually gave rise. The correct issue was, assuming Mr Hill suffered from PTSD as defined in cl 4 of the SoP, did the material raise or point to his "experiencing a stressor", as defined, during his operational service? There was no dispute that Mr Hill had PTSD. Had the Tribunal considered the matter on this basis, it may, perhaps, have reached a different conclusion (although this really does not matter). The fundamental character of the error invalidates the finding of the Tribunal on the question to which ss 120(3) and 120A(3) give rise. As the Full Court said in Commonwealth Banking Corporation v Percival (1988) 20 FCR 176 at 182:
The Administrative Appeals Tribunal is … required by s 43 of the Administrative Appeals Tribunal Act 1975 (Cth), when giving its decision, to state the reasons for it, to set out its findings of fact and to make reference to the evidence upon which those facts were found. That is an obligation which the Tribunal undertook in the present case and its reasons are lengthy, careful and detailed. Such reasons ought not to be examined with an unduly critical or technical eye but should be read fairly with each sentence being weighed up and considered in the context of the whole.
If, on the reading of suchreasons, an error of law appears, either by express statement or by necessary implication and if that error of law affected the decision reached, then the decision must be set aside. If a material error of law is so identified, it is of no consequence that the decision reached could have been supported on a different basis … .