Can a plaintiff rely on Rule 21.01(1)(a) to secure advice of the court about the soundness of its cause of action?

Second, a plaintiff may not use Rule 21 to secure the advice of the court about the soundness of its cause of action by asking the court to assume that the material facts it has pleaded will be proved at trial. This point was canvassed later by a divided Court of Appeal in Law Society of Upper Canada v. Ernst & Young, [See Note 10 below] a case in which the defendants moved for summary judgment and under rule 21.01(1)(a) after they had filed their defences. In that case, Borins J.A. disapproved of parties resorting to rule 21.01(1)(a) on the basis of facts assumed only for the [page24 ]purpose of the motion when a dispute otherwise existed over material facts and liability. He concluded that it was "not the purpose of rule 21.01(1)(a) to enable a party to obtain the advisory opinion of the court as to the validity of its cause of action or defence where the facts that constitute the substratum thereof are in dispute". [See Note 11 below] McMurtry C.J.O. and Carthy J.A. disagreed with the breadth of that statement, holding that "the hypothetical to be avoided is one where an underpinning of the legal determination sought under Rule 21 may be altered at trial, and the legal determination thus rendered redundant". [See Note 12 below]