Where the plaintiff cannot establish the cause of her injury, but must speculate without evidence, the plaintiff cannot establish proximate cause on the part of the defendant.The 1st District Appellate Court affirmed the decision of Cook County Circuit Judge William Gomolinski.Pamela Ward was a tenant at 4851 N. Damen Ave., a building owned by Nicolae and Elena Toma. On Feb. 2, 2011, as Ward was entering the building and walking down a staircase leading from the front door into the lobby, she slipped and fell, injuring …