What is the legal tenability of a motion to amend a statement of claim?

The approach for determining legal tenability was summarized by Fregeau J. in Essa v. Panontin, 2010 ONSC 691 at para. 8: “To be allowed, the amendments requested by the Plaintiffs must be tenable at law. On a motion to add a party and/or to amend the statement of claim against existing parties, the court may not consider the factual and evidentiary merits of the proposed new claims. A court is not to concern itself with the credibility of the case set forth by a party seeking an amendment. The court, in its analysis, is not to consider whether the amending party is able to prove the amended claim. The court must assume the facts pleaded in the proposed amendment are true. The only question is whether they disclose a tenable cause of action. The court is not to make findings of fact or weigh evidence. Amendments are to be read generously with allowance for deficiencies in drafting.”