Common sense inferences may not always apply

The recent decision of R v McConnell, 2012 ABQB 263 points out that the "common sense" inference that someone intends the natural result of their actions may not always apply in the context of intoxication:

In this case, the Crown urges the Court to apply the common sense inference that a sane and sober person intends the natural consequences of her actions. Such an inference is just that ‑ an inference ‑ and, as with any inference, its application depends on the circumstances of the case. As stated by Joyce, J. in R v Robinson, 2010 BCSC 368 (CanLII), 2010 BCSC 368 at para 107, and cited in R v Damin, 2011 BCSC 723 (CanLII), 2011 BCSC 723 at para 33:

But there may be circumstances that cast doubt on whether one can safely rely on the common sense inference. Such circumstances include intoxication, whether by alcohol or drugs. In addition, evidence of a mental condition that falls short of a mental disorder that renders the accused not criminally responsible, may raise a reasonable doubt as to whether the accused had the necessary specific intent. If such circumstances, either alone or in combination, raise a reasonable doubt that the accused had the subjective intent to cause bodily harm or that he had the subjective knowledge that the bodily harm he inflicted was of such a nature that it was likely to result in death, then the accused is entitled to the benefit of that doubt and cannot be convicted of murder