The defence of provocation requires that there be a wrongful act or insult of such a nature that it is sufficient to deprive an ordinary person of the power of self‑control and that the accused act on that insult before there was time for her passion to cool.
In order to satisfy the objective element of the defence, the evidence must be capable of giving rise to a reasonable doubt that an ordinary person in the accused’s circumstances would be deprived of the power of self‑control when hearing insults about his or her level of education.
232. (1) Culpable homicide that otherwise would be murder may be reduced to manslaughter if the person who committed it did so in the heat of passion caused by sudden provocation.
(2) A wrongful act or an insult that is of such a nature as to be sufficient to deprive an ordinary person of the power of self-control is provocation for the purposes of this section if the accused acted on it on the sudden and before there was time for his passion to cool.
(3) For the purposes of this section, the questions
(a) whether a particular wrongful act or insult amounted to provocation, and
(b) whether the accused was deprived of the power of self-control by the provocation that he alleges he received,
are questions of fact, but no one shall be deemed to have given provocation to another by doing anything that he had a legal right to do, or by doing anything that the accused incited him to do in order to provide the accused with an excuse for causing death or bodily harm to any human being.
The Court has held that a defence should only be put to the jury if it has an “air of reality” (R. v. Cinous, 2002 SCC 29 (CanLII),  2 S.C.R. 3, at para. 50). The air of reality test imposes two duties on the trial judge: to “put to the jury all defences that arise on the facts, whether or not they have been specifically raised by an accused”; and “to keep from the jury defences lacking an evidential foundation” (Cinous, at para. 51). Whether a defence arises on the evidence of the accused or of the Crown, the trial judge must put the defence to the jury if it has an air of reality (Cinous, at para. 53;R. v. Osolin, 1993 CanLII 54 (SCC),  4 S.C.R. 595).
In determining whether a defence has an air of reality, there must be an examination into the sufficiency of the evidence. It is not enough for there to be “some evidence” supporting the defence (Cinous, at para. 83). The test is “whether there is (1) evidence (2) upon which a properly instructed jury acting reasonably could acquit if it believed the evidence to be true” (Cinous, at para. 65). For defences that rely on indirect evidence or defences like provocation that include an objective reasonableness component, the trial judge must examine the “field of factual inferences” that can reasonably be drawn from the evidence (Cinous, at para. 91).
Source: R. v. Mayuran, 2012 SCC 31.