defining probability theory

Encyclopedia Britannia defines probability theory as "Branch of mathematics that deals with analysis of random events." The wikipedia article quotes this definition as its opening statement. J M Steele for the University of Pennsylvania writes that "Probability theory is that part of mathematics that aims to provide insight into phenomena that depend on chance or on uncertainty." Let us try to mash them up. 

Probability theory is the branch of math that deals with uncertain events. 

How does that look? Please let me know.