Vandermark (P) purchased a Ford automobile. He had used it for just 1,500 miles when he was braking, and the car started to dive to the right and continued across two lanes of traffic until it hit the shoulder. P took the car to the dealership to have it serviced and mentioned the problem, but the dealer records did not record it. While driving it again, it started to shimmy and weave and pulling to the right. P applied the brakes to stop the problem and all of a sudden he smashed into a pole. A witness testified to the same facts as P and said that the car started to swerve and skidded into a light post. P sued for breach of warranty and negligence. At trial, P called an expert on automobile brakes. In his opinion, it was a defect in the brakes that caused the accident and caused P to lose control of the car. However, the trial court struck the testimony on possible causes for the failure of the piston to retract on the ground that there was no direct evidence that any one or more of the causes existed and it rejected P’s offer to prove that all possible causes were attributable to D. The trial court granted a motion for a nonsuit on all causes of action and directed a verdict in favor of D. This appeal resulted.