Optimists can be described as "cup half full" people- those who look on the bright side of things. Pessimists, however, are described as "cup half empty" people.
Now, take a moment to thing about this. Optimists are "cup half full", in other words, they can be described as Cup = 1/2 x Full. Allow Full to equal one, and you see that the optimists' cup has half as much as it can hold.
Pessimists are "cup half empty": Cup = 1/2 x Empty. Now, empty is obviously equivalent to zero, correct? And any number times 0 is 0. Therefore, a pessimists outlook on life is Cup=0.
That's like saying that the "cup" (outlook on life) doesn't even exist! But all humans exist, or else they would not be alive. And in order to be the living, rational creatures that humans are, you must have some sort of outlook on life.
Therefore, it is mathematically impossible to be a pessimist!
