To come within that provision there must be a loss or outgoing actually incurred. "Incurred" does not mean only defrayed, discharged, or borne, but rather it includes encountered, run into, or fallen upon. It is unsafe to attempt exhaustive definitions of a conception intended to have such a various or multifarious application. But it does not include a loss or expenditure which is no more than impending, threatened, or expected.
Obviously, the fact that a liability to make a future payment is theoretically contingent or defeasible is a relevant consideration. For the purpose of ascertaining taxable income on an accruals basis, however, it will not of itself be decisive against deductibility under s. 51(1) unless, in the circumstances of the particular case, the contingency or defeasibility precludes the liability from constituting, or giving rise to, a "loss or outgoing" which has been "incurred" in the sense explained by Dixon J. in the above passage, that is to say, "encountered, run into, or fallen upon" as distinct from being "no more than impending, threatened, or expected". In that regard, it is important to bear in mind that Dixon J.'s explanation of the import of the words "loss or outgoing incurred" in a taxation provision [29] which relevantly corresponded with s. 51(1) was propounded by his Honour in the context of determining the deductibility of a liability to pay interest at a future time which his Honour expressly recognized as being theoretically "contingent". Indeed, the actual decision of the Court in New Zealand Flax was that so much of that contingent liability to pay money in the future as was "referable" [30] or "properly attributable" [31] to the tax year in question was deductible as a "loss or outgoing" which had been "incurred".
1. See Federal Commissioner of Taxation v James Flood Pty Ltd (1953), 88 C.L.R., at p. 506; Commercial Union Assurance Co. of Australia Ltd. v Federal Commissioner of Taxation (1977), 32 F.L.R., at p. 43; 14 A.L.R., at pp. 661-662; 7 A.T.R., at p. 444; 77 A.T.C. 4186, at p. 4193.
2. (1938) 61 C.L.R. 179, at pp. 207, 208.
3. (1953) 88 C.L.R., at p. 507.
4. Income Tax Assessment Act 1922-1934 Cth, s. 23(1)(a).
5. (1938) 61 C.L.R., at p. 193, per Rich J.
6. ibid., at p. 207, per Dixon J.