Case: East v Repatriation Commission (1987) 16 FCR 517
Outcome: considered
In Bull v Repatriation Commission , at 330 [16] Emmett and Allsop JJ regarded the exposition of a ' reasonable hypothesis ' in East v Repatriation Commission (1987) 16 FCR 517, as authoritative. In East the Court said this (at 532-533): 'The adoption of Brennan J's notion [in his dissenting judgment in Repatriation Commission v O'Brien [1985] HCA 10 ; (1985) 155 CLR 422] of a reasonable hypothesis meant that Parliament was requiring something by way of a causal link, but which fell short of proof of the link even prima facie as a fact. The meaning of the phrase "reasonable hypothesis" was felicitously explained by a Veterans' Review Board ... "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. At the same time, however, a hypothesis may be reasonable without having been proved (either on the balance of probability or beyond reasonable doubt) to be correct as a matter of fact. Were it otherwise, it would no longer be a hypothesis but would have been elevated to some higher status. Accordingly a connection asserted by a hypothesis to exist between death or incapacity and service may still be reasonable even though theoretical, and it may be theoretical in either or both of a least two senses: by postulating a known medical fact but in circumstances not known to have definitely existed in the instant case; or by postulating a medical principle which science is not yet able to definitely prove but is unable to describe as unreasonable." We agree with this analysis. A reasonable hypothesis requires more than a possibility, not fanciful or unreal, consistent with the known facts. It is an hypothesis pointed to by the facts, even though not proved upon the balance of probabilities '. (Emphasis added.) 27 In Bull v Repatriation Commission , Emmett and Allsop JJ made the following comment (at 331 [18]) about East : 'The Court said that an hypothesis is not reasonable if it is obviously fanciful or impossible or incredible or not tenable or too remote or too tenuous. However, the Full Court did not say that if an hypothesis was not obviously fanciful or not impossible, or not incredible or tenable or not too remote or not too tenuous, it was therefore necessarily reasonable. The material must point to the connecting hypothesis ...' (Emphasis in original.) Their Honours observed (at 331 [21]) that there is no doubt that the AAT is obliged to look at all the material, not just some of it and that at this point it is not entitled to find facts or reject matters.