At a purely formal level, one could call probability theory the study of measure spaces with total measure one, but that would be like calling number theory the study of strings of digits which terminate.
Terence TaoPointing out that countless great mathematicians had tried to solve the problem and failed before you came along is in particularly bad taste and should be avoided completely.
Terence Tao... it can often be profitable to try a technique on a problem even if you know in advance that it cannot possibly solve the problem completely.
Terence Tao