(a) It is only if the objective threshold test is satisfied (that of whether or not the wrongful act or insult was sufficient to deprive an ordinary person of the power of self-control) that it becomes necessary to consider the subjective question whether the accused was, in fact, deprived of his or her self-control (page 324).
(b) The objective standard exists so as to ensure that "there is no fluctuating standard of self-control against which accuseds [sic] are measured", with the governing principles being "those of equality and individual responsibility, so that all persons are held to the same standard notwithstanding their distinctive personality traits and varying capacities to achieve the standard" (Reg v Hill [1986] 1 SCR 313 at 343, per Wilson J) (page 324).
(c) However, the objective test is not to be applied in a vacuum or without regard to such of the accused's personal characteristics, attributes or history as served to identify the implications and to affect the gravity of the particular wrongful act or insult (page 324).
(d) In order to answer the central question posed by the objective test, that of whether the wrongful act or insult be of such a nature as to be sufficient to deprive an ordinary person of the power of self-control, the content and relevant implications of the wrongful act or insult must be identified and an objective assessment of its gravity in the circumstances of the particular case made (pages 325 and 326). See also Moffa, above, at 616, per Gibbs J, and 606, per Barwick CJ.
(e) The content and extent of the provocative conduct must be assessed from the viewpoint of the particular accused and, in that regard, none of the attributes or characteristics of that accused will necessarily be irrelevant to an assessment of the content and extent of the provocation. Age, sex, race, physical features, personal attributes, personal relationships, past history and even, in some circumstances, mental instability or weakness of an accused may be among the relevant attributes or characteristics (page 326).
(f) The function of "the ordinary person" for this purpose is that of providing an objective and uniform standard of the minimum powers of self-control which must be observed before the defence of provocation can reduce what would otherwise be murder to manslaughter (page 327).
(g) While personal characteristics or attributes of the particular accused may be taken into account for the purpose of assessing the content and extent of the provocation or, as their Honours put it at page 327, "for the purpose of understanding the implications and assessing the gravity of the wrongful act or insult", the ultimate question posed by the threshold objective test relates to the possible effect of the wrongful act or insult, so understood and assessed, upon the power of self-control of a truly hypothetical ordinary person, unaffected by the personal characteristics or attributes of the particular accused, age aside. In considering what is the extent of the power of self-control of that hypothetical ordinary person, the Court will be affected by contemporary conditions and attitudes (see also Moffa, above, at 616 - 617, per Gibbs J and Parker v The Queen [1963] HCA 14; (1963) 111 CLR 610 at 654, per Windeyer J).
(h) The "ordinary person" is not the "reasonable man" in the law of negligence as "it is all but impossible to envisage circumstances in which a wrongful act or insult would so provoke the circumspect and careful reasonable man of the law of negligence that, not acting in self-defence, he would kill his neighbour in circumstances which would, but for the provocation, be murder" (page 328).
(i) The assumption underlying the objective test is not that to do an act which would otherwise be murder may be an ordinary or reasonable reaction to a wrongful act or insult, but that a wrongful act or insult may be such as to be sufficient to provoke an ordinary person to lose his or her self-control to the extent that that person does the unreasonable and extraordinary (page 329).
(j) The principle of equality before the law requires that differences between different classes or groups be reflected only in the limits within which a particular level of self-control can be categorised as ordinary. The lowest level of self-control which falls within those limits or that range is required of all members of the community, subject to the qualification that, in at least some circumstances, the age of the accused should be attributed to the ordinary person (page 329). This exception could be justified, the Court said (at 330), "since the process of development from childhood to maturity is something which, being common to us all, is an aspect of ordinariness".