Canada’s Patent Act defines an invention as “any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement in any art, process, machine, manufacture or composition of matter”. The sole statutory exclusion to patentability is “mere scientific principle[s] or abstract theorem[s]”. Yet despite such permissive drafting, Canadian courts, tribunals and the Canadian Intellectual Property Office have increasing excluded other types of subject matter from patentability. I argue that most of these decisions and practice notices are flawed and inconsistent with the language of Canada’s Patent Act and its purpose. I also highlight the problem of extrapolating single judicial decisions (or a series of appeals) into even ‘grander’ exclusions. By examining not only Canadian patent law, but that of the US and UK, I will show that the exclusion of the 'unholy triumvirate' (natural phenomena, laws of nature and abstract ideas) is the only rational baseline from which courts should exclude patentable subject matter (if not codified by statute).