Legal Question in Personal Injury in Illinois

It is Latin for "The thing speaks for itself" and is a legal presumption in certain kinds of negligence cases in particular that requires no particular proof of negligence, but instead shifts the burden to the party being blamed, to come up with a rational explanation OTHER than negligence, for the alleged behavior. Here's a "classic example": car skids off the road on a bright, clear, sunny day on dry pavement, into an overpass support column, totalling the car. The "presumption" says that normally without some kind of neglience on the part of the car operator things like this don't happen. An example of negligence would include falling asleep at the wheel or, worst yet in today's world, being distracted by texting someone while driving. An example of how this presumption can be overcome is to show that the car steering suddenly failed and that there was a recall notice for faulty steering linkage on this particular car that the owner/driver was not aware of yet.