Logic: another thing that One Direction isn't very good at.

One Direction has something in common with penguins: not being particularly gifted in logic.

Take the song "What Makes You Beautiful", for instance.  The lyrics say, "You don't know you're beautiful, and that's what makes you beautiful."

Let the variable K represent knowing that you are beautiful, and let the variable B represent you actually being beautiful.  The song says

~K => B

If you do not know you are beautiful, then you are beautiful.  This is logically equivalent to the contrapositive, which is

~B => K

If you are not beautiful then you know that you are beautiful.  This, of course, makes absolutely no sense.

Perhaps One Direction meant cause and effect to flow the other way.  Instead of not knowing one's beauty being sufficient for one being beautiful, perhaps not knowing one's beauty is necessary for being beautiful.  This would be

B => ~K

If you are beautiful, then you don't know that you are beautiful.  That seems closer to what they are trying to say.  The logically equivalent contrapositive in this case is

K => ~B

If you know that you are beautiful, then you are not beautiful.  This doesn't seem quite right either.  How can anyone know that they are beautiful if they are, in fact, not beautiful?  And there are plenty of people who are beautiful, and, having healthy self-esteem, know that they are beautiful, which in no way diminishes their beauty.

Thus, neither interpretation of the lyrics is logically sound.  Perhaps there is an implied premise.  For example

(B and ~K) => B

If you are beautiful and you don't know that you are beautiful, then you are beautiful.  This also sounds like what they might be trying to say.  In this case, however, the conclusion is merely reiterating a premise, which is a logical "duh".  This is kind of like saying "if I am a silver hippo and the universe as we know it is coming to an end, then I am a silver hippo."

In conclusion, I am a silver hippo.