One might think that to assert a conjunction is the same as asserting the conjuncts. However, the lottery paradox shows that this is false. I can relatively unproblematically say: "One of x1,...,xN will win. x1 won't win. ... xN won't win." But if I said "One of x1,...,xN will win and x1 won't win and ... and xN won't win", then I would have said something I know to be necessarily false.